U.S. patent number RE36,280 [Application Number 08/057,113] was granted by the patent office on 1999-08-24 for focus adjustment information forming device.
This patent grant is currently assigned to Canon Kabushiki Kaisha. Invention is credited to Yasuteru Ichida, Takashi Kawabata, Hidetoshi Masuda, Hiroshi Miyanari, Eiji Nishimori, Yukio Odaka, Toshiaki Shingu.
United States Patent |
RE36,280 |
Kawabata , et al. |
August 24, 1999 |
Focus adjustment information forming device
Abstract
Disclosed is a focus adjustment information forming device of
the kind arranged to measure distances at a plurality of distance
measuring areas on a picture plane specified by optical means which
has its focal point being adjusted and to form information on
adjustment of the focal point, the plurality of distance measuring
areas including a center distance area located approximately in the
center of the picture plane. The device comprises first priority
means for giving priority to a measured distance value which
represents the nearest distance among measured distance values
obtained from the distance measuring areas; a second priority means
for giving priority to the measured distance value obtained from
the center distance measuring area according to its relations to
the measured distance values of other distance measuring areas when
one of the measured distance values of the distance measuring areas
other than the center distance measuring area represents the
nearest distance; and focus adjustment information forming means
for forming information on adjustment of the focal point of the
optical means on the basis of outputs of the first and second
priority means.
Inventors: |
Kawabata; Takashi (Kanagawa,
JP), Odaka; Yukio (Kanagawa, JP), Miyanari;
Hiroshi (Kanagawa, JP), Nishimori; Eiji (Tokyo,
JP), Shingu; Toshiaki (Kanagawa, JP),
Ichida; Yasuteru (Tokyo, JP), Masuda; Hidetoshi
(Kanagawa, JP) |
Assignee: |
Canon Kabushiki Kaisha (Tokyo,
JP)
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Family
ID: |
26444547 |
Appl.
No.: |
08/057,113 |
Filed: |
May 4, 1993 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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344260 |
Apr 27, 1989 |
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Reissue of: |
693773 |
Apr 26, 1991 |
05121151 |
Jun 9, 1992 |
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Foreign Application Priority Data
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Apr 28, 1988 [JP] |
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63-103983 |
Apr 24, 1989 [JP] |
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1-104266 |
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Current U.S.
Class: |
396/49; 396/122;
706/900 |
Current CPC
Class: |
G02B
7/285 (20130101); Y10S 706/90 (20130101) |
Current International
Class: |
G02B
7/28 (20060101); G03B 003/00 () |
Field of
Search: |
;354/400,402,403,404,405,406,407,408,432 ;396/49,122 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Fuzzy Set Theory and Its Applications, H.J. Zimmermann, Kluwer
Academic Publishers, 1985, pp. 11-14..
|
Primary Examiner: Adams; Russell
Attorney, Agent or Firm: Robin, Blecker & Daley
Parent Case Text
This is a continuation under 37 CFR 1.62 of prior application Ser.
No. 344,260, filed Apr. 27, 1989, now abandoned.
Claims
What is claimed is:
1. A focus adjustment information forming device, comprising:
(a) detection means for detecting signals depending on distances to
objects existing in a plurality of directions relative to a
photographic scene, and
(b) a focus adjustment information forming means for forming a
focus adjustment information centering on an object existing in a
central target direction in response to said detection means when
the distances to the objects in said plurality of directions are in
mutual relations of a long distance in a marginal target direction
toward one marginal portion of said photographic scene, an
intermediate distance in said central target direction toward a
central portion of said photographic scene and a short distance in
another marginal target direction toward another marginal portion
of said photographic scene.
2. A device according to claim 1, wherein said focus adjustment
information forming means includes means for forming a focus
adjustment information centering on the object existing in said
another marginal target direction when the distances of the objects
existing in the plurality of distances are not in said mutual
relation of the long distance in the one marginal target direction,
the intermediate distance in the central target direction and the
short distance in the another marginal target direction and are in
a mutual relation wherein the distance in the one marginal target
direction is shorter than the distances in the central target
direction and the another marginal target direction.
3. A device according to claim 2, wherein said focus adjustment
information forming means includes means for forming a focus
adjustment information centering on the object existing in the
central target direction when the distances of the objects existing
in the plurality of directions are not in the mutual relation
wherein the distance in the one marginal target direction is long,
the distance in the central target direction is intermediate, and
the distance in the another marginal target direction is short, and
are not in a mutual relation wherein the distance in the one
marginal target direction is shorter than the distances in the
central and the another marginal target directions.
4. A device according to claim 1, wherein said focus adjustment
information forming means includes means for forming a focus
adjustment information centering on the object existing in the
central target direction when the distances of the objects existing
in the plurality of directions are not in the mutual relation
wherein the distance in the one marginal target direction is long,
the distance in the central target direction is intermediate, and
the distance in the another marginal target direction is short, and
are in a mutual relation wherein the distance in the another
marginal target direction is shorter than the distances in the
central target direction and in the one marginal target
direction.
5. A device according to claim 4, wherein said focus adjustment
information forming means includes means for forming a focus
adjustment information centering on the object existing in the
central target direction when the distances of the objects existing
in the plurality of directions are not in the mutual relation
wherein the distance in the one marginal target direction is long,
the distance in the central target direction is intermediate, and
the distance in the another marginal target direction is short, and
are not in a mutual relation wherein the distance in the another
marginal target direction is shorter than the distances in the
central target direction and in the one marginal target
direction.
6. A device according to claim 1, wherein said focus adjustment
information forming means includes a program operation circuit.
7. A device according to claim 1, wherein said focus adjustment
information forming means includes an analog operation circuit.
8. A device according to claim 1, wherein said focus adjustment
information forming means includes means for judging said long
distance, said intermediate distance and said short distance on the
basis of their absolute distances.
9. A device according to claim 1, wherein said focus adjustment
information forming means includes means for judging said long
distance, said intermediate distance and said short distance on the
basis of their relative distances.
10. A device according to claim 1, wherein said focus adjustment
information forming means includes means for judging said long
distance, said intermediate distance and said short distance in
view of a depth of field. .Iadd.
11. A camera comprising:
measuring means for outputting information associated with an
object to be photographed;
a fuzzy computer for receiving an output from the measuring means
as an input value, obtaining a fitting degree of the input value
with respect to a then-part membership function in accordance with
an if-part membership function and the then-part membership
function, both of which correspond to a plurality of rules
representing a degree of influence of the input value on an optimal
exposure, obtaining a center of gravity value from a plurality of
fitting degree corresponding to the rules, and obtaining a
determination value as a result of inference; and
means for determining photographic conditions from the
determination value from the fuzzy computer and the output from
said measuring means..Iaddend..Iadd.12. A camera according to claim
11, wherein said measuring means includes photometric means for
outputting a plurality of object brightness signals including a
signal representing a brightness level of at least a central
portion of the object..Iaddend..Iadd.13. A camera according to
claim 12, wherein said measuring means further includes distance
measuring means for outputting distance data of the
object..Iaddend..Iadd.14. A camera according to claim 11, wherein
the photographic conditions include an exposure value and data
representing a light emission enable/disable state of an electronic
flash..Iaddend..Iadd.15. An exposure value operation apparatus for
a camera, comprising:
photometric means for outputting a plurality of object brightness
signals including a signal representing a brightness level of at
least a central portion of an object;
a fuzzy computer for receiving an output from said photometric
means as an input value, obtaining a fitting degree of the input
value with respect to a then-part membership function from an
if-part membership function and the then-part membership function,
both of which correspond to a plurality of rules representing a
degree of influence of the input value on an exposure state,
obtaining a center of gravity value from a plurality of fitting
degrees corresponding to the rules, and obtaining a determination
value as an inference result; and
operating means for determining weighting of the brightness signal
from said photometric means to obtain an exposure value in
accordance with the
determination value from said fuzzy computer..Iaddend..Iadd.16. An
exposure value operation apparatus for a camera, comprising:
photometric means for outputting a plurality of object brightness
signals including a signal representing a brightness level of at
least a central portion of an object;
distance measuring means for outputting distance data of the
object;
a fuzzy computer for receiving outputs from said distance measuring
means and said photometric means as input values, obtaining a
fitting degree of the input values with respect to a then-part
membership function from an if-part membership function and the
then-part membership function, both of which correspond to a
plurality of rules representing a degree of influence of the input
values on an exposure state, obtaining a center of gravity value
from a plurality of fitting degrees corresponding to the rules, and
obtaining a determination value as an inference result; and
operating means for determining weighting of the brightness signal
from said photometric means to obtain the exposure value in
accordance with the determination value from said fuzzy
computer..Iaddend..Iadd.17. An electronic flash control apparatus
for a camera, comprising:
photometric means for outputting a plurality of object brightness
signals including a signal representing a brightness level of at
least a central portion of an object;
a fuzzy computer for receiving an output from said photometric
means as an input value, obtaining a fitting degree of the input
value with respect to a then-part membership function from an
if-part membership function and the then-part membership function,
both of which correspond to a plurality of rules representing a
degree of influence of the input value on electronic flash control,
obtaining a center of gravity value from a plurality of fitting
degrees corresponding to the rules, and obtaining a determination
value as an inference result; and
electronic flash control means for controlling a light emission
enable/disable state of an electronic flash by the determination
value from said fuzzy computer..Iaddend..Iadd.18. An exposure
determining apparatus for a camera having means for measuring a
brightness distribution of an object, comprising:
a fuzzy computer for obtaining fitness degrees against exposure
conditions represented as a plurality of membership functions in
accordance with input values corresponding to brightness
distribution states of an object and outputting as a determination
value an inference result determined by operations for obtaining a
center of gravity value from said plurality of fitness degrees;
control means for determining an exposing condition on the basis of
the determination value; and
a control target object driven by an output from said control
means..Iaddend..Iadd.19. An apparatus according to claim 18,
wherein said control means includes at least one of an exposure
value operation circuit, an electronic flash light emission
enable/disable control circuit, and an electronic flash light
emission angle control circuit..Iaddend..Iadd.20. An apparatus
according to claim 18, wherein the target object includes at least
one of a shutter, an aperture, and an electronic
flash..Iaddend..Iadd.21. A camera comprising:
measuring means for outputting information associated with an
object to be photographed;
a fuzzy operation circuit for receiving an output from the
measuring means as an input value, obtaining a fitting degree of
the input value with respect to a then-part membership function in
accordance with an if-part membership function and the then-part
membership function, both of which correspond to a plurality of
rules representing a degree of influence of the input value on an
optimal exposure;
a defuzzifier operation circuit for obtaining a determination value
as a result of inference in correspondence with a center of gravity
value obtained from said fitting degree; and
means for determining photographic conditions from the
determination value from the defuzzifier operation circuit and the
output from the measuring means..Iaddend..Iadd.22. A camera
according to claim 21, wherein the if-part membership function is a
function in which an axis of abscissa corresponds to the output
from the measuring means and an axis of ordinate corresponds to the
degree of influence from 0 to 1, and the then-part membership
function is a function in which the axis of abscissa corresponds to
a correction value, and the axis of ordinate corresponds to the
degree of influence from 0 to 1..Iaddend..Iadd.23. An exposure
value operation apparatus for a camera, comprising:
photometric means for outputting a plurality of object brightness
signals including a signal representing a brightness level of at
least a central portion of an object;
a fuzzy operation circuit for receiving an output from the
photometric means as an input value, obtaining a fitting degree of
the input value with respect to a then-part membership function
from an in-part membership function and the then-part membership
function, both of which correspond to a plurality of rules
representing a degree of influence of the input value on an
exposure state;
a defuzzifier operation circuit for obtaining a center of gravity
value form a plurality of fitting degrees corresponding to the
rules, and obtaining a determination value as an inference result;
and
operating means for determining weighting of the brightness signal
from said photometric means to obtain an exposure value in
accordance with the determination value from the defuzzifier
operation circuit..Iaddend..Iadd.24. An exposure value operation
apparatus for a camera, comprising:
photometric means for outputting a plurality of object brightness
level of at least a central portion of an object;
distance measuring means for outputting distance data of the
object;
a fuzzy operation circuit for receiving an output from the distance
measuring means and the photometric means as input values,
obtaining a fitting degree of the input values with respect to as
then-part membership function from an if-part membership function
and the then-part membership function, both of which correspond to
a plurality of rules representing a degree of influence of the
input values on an exposure state;
a defuzzifier operation circuit for obtaining a center of gravity
value in correspondence with an output from the fuzzy operation
circuit, and obtaining a determination value as an inference
result; and
operating means for determining weighting of the brightness signal
from said photometric means to obtain an exposure value in
accordance with the determination value from the defuzzifier
operation circuit..Iaddend..Iadd.25. An exposure value operation
apparatus for a camera, comprising:
photometric means for outputting a plurality of object brightness
signals including a signal representing a brightness level of at
least a central portion of an object;
a fuzzy operation circuit for receiving an output from the
photometric means as an input value, obtaining a fitting degree of
the input value with respect to a then-part membership function
from an if-part membership function and the then-part membership
function, both of which correspond to a plurality of rules
representing a degree of influence of the input value on electronic
flash control;
a defuzzifier operation circuit for obtaining a center of gravity
value from a plurality of fitting degrees corresponding to the
rules, and obtaining a determination value as an inference result;
and
electronic flash control means for controlling a light emission
enable/disable state of an electronic flash by the determination
value from the defuzzifier operation circuit..Iaddend..Iadd.26. A
method for determining photographic conditions to be used in
controlling a camera, comprising the steps of:
providing information associated with an object to be
photographed;
receiving said information as an input value to a fuzzy operation
circuit, obtaining a fitting degree of the input value with respect
to a then-part membership function in accordance with an if-part
membership function and the then-part membership function, both of
which correspond to a plurality of rules representing a degree of
influence of the input value on an optimal exposure;
obtaining with a defuzzifier operation circuit a center of gravity
value as a result of inference in correspondence with an output
from the fuzzy operation circuit; and
determining photographic conditions from the determination value
from the defuzzifier operation circuit and said
information..Iaddend..Iadd.27. A camera according to claim 26,
wherein the if-part membership function is a function in which an
axis of abscissa corresponds to the output from the measuring means
and an axis of ordinate corresponds to the degree of influence from
0 to 1, and the then-part membership function is a function in
which the axis of abscissa corresponds to a correction value, and
the axis of ordinate corresponds to the degree of influence from 0
to 1..Iaddend..Iadd.28. An exposure value operation method for a
camera, comprising the step of:
outputting with a photometric means a plurality of object
brightness signals including a signal representing a brightness
level of at least a central portion of an object;
receiving an output from the photometric means as an input value to
a fuzzy operation circuit, obtaining a fitting degree of the input
value with respect to a then-part membership function from an
if-part membership function and the then-part membership function,
both of which correspond to a plurality of rules representing a
degree of influence of the input value on an exposure state;
obtaining with a defuzzifier operation circuit a center of gravity
value from a plurality of fitting degrees corresponding to the
rules, and obtaining a determination value as an inference result;
and
determining weighting of the brightness signal from the photometric
means to obtain an exposure value in accordance with the
determination value from the defuzzifier operation
circuit..Iaddend..Iadd.29. An exposure value operation method for a
camera, comprising the steps of:
outputting with photometric means a plurality of object brightness
levels of at least a central portion of an object;
outputting with distance measuring means distance data of the
object;
receiving outputs from the distance measuring means and the
photometric means as input values to a fuzzy operation circuit,
obtaining a fitting degree of the input values with respect to a
then-part membership function from an if-part membership function
and the then-part membership function, both of which correspond to
a plurality of rules representing a degree of influence of the
input values on an exposure state;
obtaining with a defuzzifier operation circuit a center of gravity
value in correspondence with an output from the fuzzy operation
circuit, and obtaining a determination value as an inference
result; and
determining weighting of the brightness signal from the photometric
means to obtain the exposure value in accordance with the
determination value from the defuzzifier operation
circuit..Iaddend..Iadd.30. An electronic flash control method for a
camera, comprising the steps of:
outputting with a photometric means a plurality of object
brightness signals including a signal representing a brightness
level of at least a central portion of an object;
receiving an output form the photometric means as an input value to
a fuzzy operation circuit, obtaining a fitting degree of the input
value with respect to a then-part membership function from an
if-part membership function and the then-part membership function,
both of which correspond to plurality of rules representing a
degree of influence of the input value on electronic flash
control;
obtaining with a defuzzifier operation circuit a center of gravity
value from a plurality of fitting degrees corresponding to the
rules, and obtaining a determination value as an inference result;
and
controlling with an electronic flash control means a light emission
enable/disable sate of an electronic flash by the determination
value from the defuzzifier operation circuit..Iaddend..Iadd.31. A
control device for an image handling apparatus, comprising:
generating means for generating information for said image handling
apparatus;
operation means for receiving an output from said generating means
as an input value, obtaining a fitting degree of the input value
with respect to a then-part membership function in accordance with
an if-part membership function and the then-part membership
function, both of which correspond to a plurality of rules
representing a degree of influence of the input value on an
operation of said image handling apparatus, obtaining a center of
gravity value from a plurality of fitting degree corresponding to
the rules, and obtaining a determination value as a result of
inference; and
means for determining a condition associated with the operation of
said image handling apparatus on the basis of the determination
value..Iaddend..Iadd.32. A device according to claim 31, wherein
said image handling apparatus includes a camera..Iaddend..Iadd.33.
A device according to claim 31, wherein said generating means
includes means for generating data on an object
distance..Iaddend..Iadd.34. A device according to claims 31 or 33,
wherein said generating means includes photometric means for
generating photometric data..Iaddend..Iadd.35. A device according
to claim 34, wherein said photometric means includes means for
generating a plurality of object brightness
signals..Iaddend..Iadd.36. A device according to claim 34, wherein
said photometric means includes means for generating photometric
data on an entire picture field..Iaddend..Iadd.37. A device
according to claim 36, wherein said photometric means includes at
least one of means for generating average photometric data on the
entire picture field and means for generating partial photometric
data on the entire picture field..Iaddend..Iadd.38. A device
according to claim 31 or claim 33, wherein said generating means
includes focal length means for generating focal length
data..Iaddend..Iadd.39. A device according to claim 38, wherein
said generating means includes means for generating diaphragm
data..Iaddend..Iadd.40. A device according to claim 31 or claim 33,
wherein said generating means includes at least one of means for
generating diaphragm data and means for generating data on a
remote-control device..Iaddend..Iadd.41. A device according to
claim 31, wherein said operation means includes means for obtaining
a value indicating a likely main object as the determination
value..Iaddend..Iadd.42. A device according to claim 31, wherein
said operation means includes means for obtaining a peak
value..Iaddend..Iadd.43. A device according to claim 31, wherein
said operation means includes means for obtaining an intermediate
value..Iaddend..Iadd.44. An optical system, comprising:
generating means for generating information for said optical
system;
operation means for receiving an output from said generating means
as an input value, obtaining a fitting degree of the input value
with respect to a then-part membership function in accordance with
an if-part membership function and the then-part membership
function, both of which correspond to a plurality of rules
representing a degree of influence of the input value on an
operation of said optical system, obtaining a center of gravity
value from a plurality of fitting degree corresponding to the
rules, and obtaining a determination value as a result of the
inference; and
means for determining a condition associated with the operation of
said optical system on the basis of the determination
value..Iaddend..Iadd.45. An optical system according to claim 44,
wherein said optical system includes a camera..Iaddend..Iadd.46. A
control device for an image handling apparatus, comprising:
generating means for generating information for said image handling
apparatus;
operating means for receiving an output from said generating means
as an input value, obtaining a fitting degree of the input value
with respect to a then-part membership function in accordance with
an if-part membership function and the then-part membership
function, both of which correspond to a plurality of rules
representing a degree of influence of the input value on an
operation of said image handling apparatus, synthetically
evaluating a plurality of fitting degree corresponding to the
rules, and obtaining a determination value as a result of
inference; and
means for determining a condition associated with the operation of
said image handling apparatus on the basis of the determination
value..Iaddend..Iadd.47. A device according to claim 46, wherein
said image handling apparatus includes a camera..Iaddend..Iadd.48.
A device according to claim 46, wherein said generating means
includes means for generating data on an object
distance..Iaddend..Iadd.49. A device according to claim 46, wherein
said generating means includes photometric means for generating
photometric data..Iaddend..Iadd.50. A device according to claim 49,
wherein said photometric means includes means for generating a
plurality of object brightness signals..Iaddend..Iadd.51. A device
according to claim 50, wherein said photometric means includes at
least one of means for generating photometric data on an entire
picture field and means for generating partial photometric data on
the entire picture field..Iaddend..Iadd.52. A device according to
claim 46, wherein said generating means includes means for
generating focal length data..Iaddend..Iadd.53. A device according
to claim 52, wherein said generating means includes means for
generating diaphragm data..Iaddend..Iadd.54. A device according to
claim 46, wherein said generating means includes at least one of
means for generating diaphragm data and means for generating data
on a remote-control device..Iaddend..Iadd.55. A device according to
claim 46, wherein said operation means includes means for obtaining
a value indicating a likely main object as the determination
value..Iaddend..Iadd.56. A device according to claim 46, wherein
said operation means includes means for obtaining a peak
value..Iaddend..Iadd.57. A device according to claim 46, wherein
said operation means includes means for obtaining an intermediate
value..Iaddend..Iadd.58. An optical system, comprising:
generating means for generating information for said optical
system;
operation means for receiving an output from said generating means
as an input value, obtaining a fitting degree of the input value
with respect to a then-part membership function in accordance with
an if-part membership function and the then-part membership
function, both of which correspond to a plurality of rules
representing a degree of influence of the input value on an
operation of said optical system, synthetically evaluating a
plurality of fitting degree corresponding to the rules, and
obtaining a determination value as a result of inference; and
means for determining a condition associated with the operation of
said optical system on the basis of the determination
value..Iaddend..Iadd.59. An optical system according to claim 58,
wherein said optical system includes a camera..Iaddend..Iadd.60. A
control device for an image handling apparatus, comprising:
generating means for generating information for said image handling
apparatus;
operation means for receiving an output from said generating means
as an input value, obtaining a fitting degree of the input value
with respect to a then-part membership function in accordance with
an if-part membership function and the then-part membership
function, wherein the then-part membership function corresponds to
a conversion rule obtaining from the input value two kinds of
values converted in accordance with a degree of probable
correctness and a value to weight the degree of probable
correctness, and obtaining a degree of influence of the input value
on an operation of said image handling apparatus by synthetically
evaluating the two kinds of converted values; and
means for determining a condition associated with an operation of
said image handling apparatus on the basis of the degree of
influence..Iaddend..Iadd.61. A device according to claim 60,
wherein said image handling apparatus includes a
camera..Iaddend..Iadd.62. A device according to claim 60, wherein
said generating means includes means for generating data on an
object distance..Iaddend..Iadd.63. A device according to claim 60,
wherein said generating means includes photometric means for
generating photometric data..Iaddend..Iadd.64. A device according
to claim 63, wherein said photometric means includes means for
generating a plurality of object brightness
signals..Iaddend..Iadd.65. A device according to claim 63, wherein
said photometric means includes means for generating photometric
data on an entire picture field..Iaddend..Iadd.66. A device
according to claim 65, wherein said photometric means includes at
least one of means for generating average photometric data on the
entire picture field and means for generating partial photometric
data on the entire picture field..Iaddend..Iadd.67. A device
according to claim 60 wherein said generating means includes means
for generating focal length data..Iaddend..Iadd.68. A device
according to claim 67, wherein said generating means includes means
for generating diaphragm data..Iaddend..Iadd.69. A device according
to claim 60, wherein said generating means includes at least one of
means for generating diaphragm data and means for generating data
on a remote-control device..Iaddend..Iadd.70. A device according to
claim 60, wherein said operation means includes means for obtaining
a value indicating a likely main object as the determination
value..Iaddend..Iadd.71. A device according to claim 60, wherein
said operation means includes means for obtaining a peak
value..Iaddend..Iadd.72. A device according to claim 60, wherein
said operation means includes means for obtaining an intermediate
value..Iaddend..Iadd.73. An optical system, comprising:
generating means for generating information for said optical
system;
operation means for receiving an output from said generating means
as an input value, obtaining a fitting degree of the input value
with respect to a then-part membership function in accordance with
an if-part membership function and the then-part membership
function, wherein the then-part membership function corresponds to
a conversion rule obtaining from the input value two kinds of
values converted in accordance with a degree of probable
correctness and value to weight the degree of probable correctness
and a value to weight the degree of probable correctness, and
obtaining a degree of influence of the input value on an operation
of said optical system by synthetically evaluating the two kinds of
converted values; and
means for determining a condition associated with an operation of
said optical system on the basis of the degree of
influence..Iaddend..Iadd.74. An optical system according to claim
73, wherein said optical system includes a
camera..Iaddend..Iadd.75. A control device for an image handling
apparatus, comprising:
generating means for generating information for said image handling
apparatus;
operation means for receiving an output from said generating means
as an input value, obtaining a fitting degree of the input value
with respect to a then-part membership function in accordance with
an if-part membership function and the then-part membership
function, both of which correspond to a plurality of rules
representing a degree of influence of the input value on an
operation of said image handling apparatus, obtaining a peak value
from a plurality of fitting degree corresponding to the rules, and
obtaining a determination value as result of inference; and
means for determining a condition associated with the operation of
said image handling apparatus on the basis of the determination
value..Iaddend..Iadd.76. A device according to claim 75, wherein
said image handling apparatus includes a camera..Iaddend..Iadd.77.
A device according to claim 75, wherein said generating means
includes means for generating data on an object
distance..Iaddend..Iadd.78. A device according to claim 75, wherein
said generating means includes photometric means for generating
photometric data..Iaddend..Iadd.79. A device according to claim 78,
wherein said photometric means includes means for generating a
plurality of object brightness signals..Iaddend..Iadd.80. A device
according to claim 78, wherein said photometric means includes
means for generating photometric data on an entire picture
field..Iaddend..Iadd.81. A device according to claim 80, wherein
said photometric means includes at least one of means for
generating average photometric data on the entire picture field and
means for generating partial photometric data on the entire picture
field..Iaddend..Iadd.82. A device according to claim 75, wherein
said generating means includes means for generating focal length
data..Iaddend..Iadd.83. A device according to claim 82, wherein
said generating means includes means for generating diaphragm
data..Iaddend..Iadd.84. A device according to claim 75, wherein
said generating means includes at least one of means for generating
diaphragm data and means for generating data on a remote-control
device..Iaddend..Iadd.85. A device according to claim 75, wherein
said operation means includes means for obtaining a value
indicating a likely main object as the determination
value..Iaddend..Iadd.86. A device according to claim 75, wherein
said operation means includes means for obtaining a peak
value..Iaddend..Iadd.87. A device according to claim 75, wherein
said operation means includes means for obtaining an intermediate
value..Iaddend..Iadd.88. An optical system, comprising:
generating means for generating information for said optical
system;
operation means for receiving an output from said generating means
as an input value, obtaining a fitting degree of the input value
with respect to a then-part membership function in accordance with
an if-part membership function and the then-part membership
function, both of which correspond to a plurality of rules
representing a degree of influence of the input value on an
operation of said optical system, obtaining a peak value from a
plurality of fitting degree corresponding to the rules, and
obtaining a determination value as a result of inference; and
means for determining a condition associated with the operation of
said optical system on the basis of the determination
value..Iaddend..Iadd.89. An optical system according to claim 88,
wherein said optical system includes a camera..Iaddend..Iadd.90. A
method for determining a condition associated with an operation of
image handling apparatus, comprising steps of:
generating information for said image handling apparatus;
receiving the information as an input value, and obtaining a
fitting degree of the input value with respect to a then-part
membership function in accordance with an if-part membership
function and the then-part membership function, both of which
correspond to a plurality of rules representing a degree of
influence of the input value on an operation of said image handling
apparatus;
obtaining a center of gravity value from a plurality of fitting
degree corresponding to the rules, and obtaining a determination
value as a result of inference; and
determining the condition associated with the operation of said
image handling apparatus on the basis of the determination
value..Iaddend..Iadd.91. A method according to claim 90, wherein
said image handling apparatus includes a camera..Iaddend..Iadd.92.
A method for determining a condition associated with an operation
of image handling apparatus, comprising steps of:
generating information for said image handling apparatus;
receiving the information as an input value, and obtaining a
fitting degree of the input value with respect to a then-part
membership function in accordance with an if-part membership
function and the then-part membership function, both of which
correspond to a plurality of rules representing a degree of
influence of the input value on an operation of said image handling
apparatus;
synthetically evaluating a plurality of rules representing a degree
of influence of the input value on an operation of said image
handling apparatus; and
determining the condition associated with the operation of said
image handling apparatus on the basis of the determination
values..Iaddend..Iadd.93. A method according to claim 92, wherein
said image handling apparatus includes a camera..Iaddend..Iadd.94.
A method for determining a condition associated with an operation
of image handling apparatus, comprising steps of:
generating information for said image handling apparatus;
receiving the information as an input value, and obtaining a
fitting degree of the input value with respect to a then-part
membership function in accordance with an if-part membership
function and the then-part membership function, wherein the
then-part membership function corresponds to a conversion rule
obtaining from the input value two kinds of values converted in
accordance with a degree of probable correctness and a value to
weight the degree of probable correctness;
obtaining a degree of influence of the input value on an operation
of said image handling apparatus by synthetically evaluating the
two kinds of converted values; and
determining the condition associated with an operation of said
image handling apparatus on the basis of the degree of
influence..Iaddend..Iadd.95. A method according to claim 94,
wherein said image handling apparatus includes a
camera..Iaddend..Iadd.96. A method for determining a condition
associated with an operation of an image handling apparatus,
comprising steps of:
generating information for said image handling apparatus;
receiving the information as a an input value, and obtaining a
fitting degree of the input value with respect to a then-part
membership function in accordance with an if-part membership
function and the then-part membership function, both of which
correspond to a plurality of rules representing a degree of
influence of the input value on an operation of said image handling
apparatus;
obtaining a peak value from a plurality of fitting degree
corresponding to the rules, and obtaining a determination value as
a result of inference; and
determining the condition associated with the operation of said
image handling apparatus on the basis of the determination
value..Iaddend..Iadd.97. A method according to claim 96, wherein
said
image handling apparatus includes a camera..Iaddend..Iadd.98. A
control device for an image handling apparatus, comprising:
generating means for generating information for said image handling
apparatus;
operation means for receiving an output from said generating means
as an input value, obtaining a fitting degree of the input value
with respect to a then-part membership function in accordance with
an if-part membership function and the then-part membership
function, wherein the then-part membership function corresponds to
a two-dimensional conversion rule obtaining from the input value
two kinds of values converted in accordance with a degree of
probable correctness and a value to weight the degree of probable
correctness, and obtaining a degree of influence of the input value
on an operation of said image handling apparatus by
one-dimensionally converting the two kinds of converted values;
and
means for determining a condition associated with an operation of
said image handling apparatus on the basis of the degree of
influence..Iaddend..Iadd.99. An optical system, comprising:
generating means for generating information for said optical
system;
operation means for receiving an output from said generating means
as an input value, obtaining a fitting degree of the input value
with respect to a then-part membership function in accordance with
an if-part membership function and the then-part membership
function, wherein the then-part membership function corresponds to
a two-dimensional conversion rule obtaining from the input value
two kinds of values converted in accordance with a degree of
probable correctness and a value to weight the degree of probable
correctness, and obtaining a degree of influence of the input value
on an operation of said optical system by one-dimensionally
converting the two kinds of converted values; and
means for determining a condition associated with an operation of
said optical system on the basis of the degree of
influence..Iaddend..Iadd.100. A method for determining a condition
associated with an operation of image handling apparatus,
comprising steps of:
generating information for said image handling apparatus;
receiving the information as an input value, and obtaining a
fitting degree of the input value with respect to a then-part
membership function in accordance with an if-part membership
function and the then-part membership function, wherein the
then-part membership function corresponds to a two-dimensional
conversion rule obtaining from the input value two kinds of values
converted in accordance with a degree of probable correctness and a
value to weight the degree of probable correctness;
obtaining a degree of influence of the input value on an operation
of said image handling apparatus by one-dimensionally converting
the two kinds of converted values; and
determining the condition associated with an operation of said
image handling apparatus on the basis of the degree of
influence..Iaddend.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an improvement on a focus adjustment
information forming device arranged to measure distances to objects
appearing at a plurality of distance measuring points (or areas)
set within a picture plane such as a photo-taking picture plane or
the like specified by optical means which is used for an optical
system such as a camera and to be focus adjusted.
2. Description of the Related Art
The devices of the above-stated kind has been known as wide-field
distance measuring devices, which have been disclosed, for example,
in Japanese Laid-Open Patent Application No. SHO 58-201015 and U.S.
Pat. No. 4,470,681. After these disclosures, devices arranged to
prevent a distance measurement error due to a foreground has been
disclosed in Japanese Laid-Open Patent Applications No. SHO
59-193307 and No. SHO 60-172008. In addition to these known
devices, a device arranged to exclude any object located nearer
than a given distance as an obstacle has been proposed in U.S.
patent application Ser. No. 184,931, etc.
However, these known wide-field distance measuring devices have
been incapable of accurately discriminating a nearby object from a
nearby obstacle such as the ground and thus have often failed to
give accurate focus adjustment information.
SUMMARY OF THE INVENTION
Such being the background situation, a principal object of the
present invention is to provide a focus adjustment information
forming device which is capable of forming reliable focus
adjustment information by accurately discriminating the measured
distance value of an object to be focused on by optical means from
other measured distance values obtained by a plurality of distance
measuring areas including one located approximately in the central
part of a picture plane.
To attain this object, a focus adjustment information forming
device arranged according to this invention to measure distances to
objects appearing at a plurality of distance measuring areas of a
picture plane specified by optical means which has its focal point
being adjusted and to form information on adjustment of the focal
point of the optical means, the plurality of distance measuring
areas including a substantially central distance measuring area
located approximately in the center of the picture plane,
comprises: first priority means for giving priority to a measured
distance value which represents the nearest distance among measured
distance values obtained from the plurality of distance measuring
areas; a second priority means for giving priority to the measured
distance value obtained from the substantially central distance
measuring area according to relations thereof to measured distance
values obtained from distance measuring areas other than the
substantially central distance measuring area when one of the
measured distance values of the distance measuring areas other than
the central distance measuring area represents the nearest
distance; and focus adjustment information forming means for
forming information on adjustment of the focal point of the optical
means on the basis of outputs of the first and second priority
means.
Other objects and features of the invention will become apparent
from the following detailed description of embodiments thereof
taken in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram showing in outline the arrangement of an
embodiment of the invention.
FIG. 2 is a flow chart showing the operation of the embodiment of
FIG. 1.
FIG. 3 is a circuit diagram showing circuit arrangement of the
embodiment for zone (area) comparison.
FIG. 4 is a circuit diagram showing a circuit arrangement of the
embodiment made with a distance difference taken into
consideration.
FIG. 5 is an analog circuit arrangement of the same embodiment.
FIG. 6 shows the input-output characteristic of an output circuit
81 of FIG. 5.
FIG. 7 is a circuit diagrams showing a circuit arrangement for
attaining the same characteristic.
FIG. 8 is a circuit diagram showing a circuit arrangement for a
probability addition to be performed on the basis of a distance
difference for the embodiment shown in FIG. 1.
FIG. 9 shows the input-output characteristic of an output circuit
120 of FIG. 8.
FIG. 10 is a circuit diagram showing a circuit arrangement for
attaining the same characteristic.
FIG. 11 is a circuit diagram showing by way of example the details
of a peak detection circuit of FIG. 8.
FIG. 12 is a flow chart showing the operation of the circuit
arrangement of FIG. 8 to be performed with a microcomputer included
therein.
FIG. 13 is a flow chart showing by way of example a programmed
operation of the same.
FIG. 14 is a circuit diagram showing a circuit arrangement for a
probability subtraction to be performed on the basis of a distance
difference for the embodiment shown in FIG. 1.
FIG. 15 is a circuit diagram showing a circuit arrangement made
according to a probability array of the same embodiment.
FIG. 16 is a circuit diagram showing by way of example the
arrangement of a barycenter computing unit of FIG. 15.
FIG. 17 is a flow chart showing the operation of the arrangement of
FIG. 15 with a microcomputer included therein.
FIG. 18 shows by way of example a programmed operation of the same
arrangement.
FIG. 19 is a block diagram showing the arrangement of FIG. 15 based
on the Fuzzy theory.
FIG. 20 is a flow chart showing the operation of the arrangement of
FIG. 19 with a microcomputer included therein.
FIG. 21 shows by way of example a programmed operation of the
same.
FIG. 22 is a circuit diagram showing a circuit arrangement for
obtaining an intermediate value through an analog computing
operation using a distance difference for the embodiment shown in
FIG. 1.
FIG. 23 is a circuit diagram showing by way of example a circuit
arrangement for obtaining an intermediate value by a probability
computation for the same embodiment.
FIG. 24 is a circuit diagram showing by way of example a
normalizing arrangement for the circuit of FIG. 23.
FIG. 25 is a circuit diagram showing by way of example a
probability array arranged to obtain an intermediate value by using
a distance difference for the embodiment of FIG. 1.
FIG. 26 shows by way of example the arrangement of the distance and
light measuring units of another embodiment of the invention.
FIGS. 27 to 29 show examples of positions of distance measuring
points arranged within the photo-taking picture plane of the same
embodiment.
FIG. 30 is a block diagram showing in outline the arrangement of a
further embodiment of the invention.
FIG. 31 is a flow chart showing an operation using a measured light
value for the same embodiment.
FIG. 32 shows by way of example a program for the operation of FIG.
31.
FIG. 33 shows the consequent membership functions of the same
program.
FIGS. 34 and 35 are illustrations showing a shutter release
operation to be performed with a camera held in vertical and
horizontal postures.
FIG. 36 is a flow chart showing the same operation.
FIG. 37 shows an example where the same operation is performed
according to a program.
FIG. 38 shows a mechanism arranged to give information on other
postures of the camera.
FIG. 39 is a flow chart showing the operation of the same
mechanism.
FIG. 40 shows an example where the same operation is performed
according to a program.
FIG. 41 is a flow chart showing the operation of an embodiment of
the invention arranged to use information on the use or nonuse of a
flash device.
FIG. 42 shows an example where the same operation is arranged to be
performed according to a program.
FIG. 43 shows a membership function for a reachable distance to be
used for other embodiments of the invention.
FIG. 44 shows a weakly affirmative membership function to be used
for other embodiments.
FIG. 45 shows a membership function for a remote-control received
signal.
FIGS. 46 to 48 show membership functions based on distance
differences.
FIG. 49 is a flow chart showing an operation performed by using
aperture-value or focal-length information.
FIG. 50 shows by way of example a program of the operation of FIG.
49.
FIGS. 51 and 52 show membership functions of the aperture-value or
focal-length information.
FIGS. 53 and 54 show membership functions for different focal
lengths.
FIG. 55 is a flow chart showing an operation performed by using a
focal length-using frequency for an embodiment of the
invention.
FIG. 56 shows by way of example a program for the operation of FIG.
55.
FIG. 57 is a block diagram showing a further embodiment of the
invention.
FIG. 58 shows distance measuring areas arranged within the
viewfinder of the same embodiment.
FIGS. 59(a) to 59(e) show typical framing examples according to the
Fuzzy rules of FIG. 21.
FIG. 60 shows Fuzzy rules employed by the embodiment of FIG.
57.
FIG. 61 schematically shows the Fuzzy rules of FIG. 60.
FIG. 62 shows by way of example a photographic framing to be
employed in the event of having nearby obstacles on both sides.
FIGS. 63(a) and 63(b) show methods generally employed for a Fuzzy
computation.
FIGS. 64, 66 to 68 and 70 show membership functions used by the
embodiment of FIG. 57.
FIGS. 65, 69 and 71 show the formulas of the membership functions
relative to the embodiment of FIG. 57.
FIG. 72 shows in outline the program of the same embodiment.
FIGS. 73 to 80 show the program examples of the same
embodiment.
FIGS. 81, 82(a), 82(b), 83(a), 83(b), 84(a), 84(b), 85(a) and 85(b)
show assembler program examples to be used for the same
embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows in a block diagram an embodiment of this invention.
The embodiment is arranged to measure distances to objects by means
of three known distance measuring units 1, 2 and 3 through left,
center (approximately in the center) and right distance measuring
points (or areas) provided within a photo-taking picture plane
(.Iadd.picture field) .Iaddend.specified by a photo-taking lens
which is not shown. An analog voltage is produced as a result of
the distance measurement. The nearer the measured distance value
DV1, DV2 or DV3 is, the lower the level of the analog voltage is. A
computing circuit 4 receives the analog voltages from the distance
measuring units 1, 2 and 3. The circuit 4 is arranged to compute
and obtain lens driving (focus adjusting) information from the
measured distance values, differences among them, information ANG
about the posture of the camera, information ST about the use or
nonuse of a flash device, information AV on an aperture value, etc.
A focus adjusting system 5 is arranged to drive and control the
lens according to the lens driving information from the computing
circuit 4.
The details of the computing operation and the arrangement of the
computing circuit 4 are as follows:
In the case of this embodiment, one of the measured distance values
obtained from the three distance measuring points is selected
through a computing operation which is performed on the basis of
the following concept: Among these measured distance values, the
nearest distance value represents an object to be photographed in
general. Hence, the nearest distance value is output as a general
rule. However, in the case of "provided that" conditions where one
of the left and right measured distance values indicates a near
distance, where the center measured distance value indicates a
medium distance and where the other of the left and right measured
distance values indicates a far distance, the measured distance
value indicating the near distance is regarded as representing a
nearby obstacle such as a ground or the like located between the
camera and the object to be photographed and, in that case, the
computing circuit 4 outputs the center measured distance value,
because: In such a case, it is highly probable that one of the
distance measuring points is facing the ground with the camera held
aslant or an obstacle such as a tree or the like is located nearby
even if the camera is in a normal posture.
In a case where the computing circuit 4 of FIG. 1 includes a
microcomputer, etc., the embodiment operates as shown in FIG. 2
which is a flow chart. In this instance, as criteria for
determining whether the camera is under the above-stated "provided
that" condition, the near distance is considered to be not
exceeding 1.5 m, the medium distance to be between 2 m and 4 m and
the far distance to be exceeding 5 m.
Referring to FIG. 2, the embodiment operates as follows: At a step
#1: A check is made to see if the measured distance value (left
measured distance value) obtained from the distance measuring unit
1 is not exceeding 1.5 m; if the measured distance value (center
measured distance value) obtained from the distance measuring unit
2 is between 2 m and 4 m; and if the measured distance value (right
measured distance value) obtained from the distance measuring unit
3 is exceeding 5 m. If these conditions are all satisfied, the
center measured distance value is selected as the current measured
distance information. If not, the flow proceeds to a step #2. At
the step #2: A check is made to see if the measured distance value
from the distance measuring unit 3 is not exceeding 1.5 m; if the
value from the unit 2 is between 2 m and 4 m; and if the value from
the unit 1 is exceeding 5 m. If these conditions are all satisfied,
the center measured distance value is selected as the current
measured distance information like in the case of the step #1. If
not, the flow proceeds to a step #3. At the step #3: A check is
made to see if the value from the unit 3 is smaller than the value
from the unit 2 and if the value from the unit 3 is smaller than
the value from the unit 1. If these conditions are all satisfied,
the measured distance value obtained from the distance measuring
unit 3 is selected as the current measured distance information. If
not, the flow proceeds to a step #4. At the step #4: A check is
made to see if the value from the unit 1 is smaller than the value
from the unit 2 and if the value from the unit 1 is smaller than
the value from the unit 3. If these conditions are satisfied, the
measured distance value from the unit 1 is selected as the measured
distance information of that point of time. If not, the value from
the unit 2 is selected as the measured distance information in the
same manner as in the cases of the steps #1 and #2.
The above stated arrangement enables the camera of the AF type to
more adequately bring the object into focus than the conventional
AF camera of a narrow distance measuring field even with framing
freely determined. Further, compared even with the conventional
camera of the kind measuring distances with a wide visual field,
the embodiment is capable of eliminating the possibility of
measuring a distance to a nearby obstacle such as the ground or the
like by mistake. Therefore, a distance to the object to be
photographed can be correctly measured without any erroneous
distance measurement.
In the case of FIG. 2, the flow chart shows a programmed operation.
However, the operation can be also executed with an analog circuit
arrangement. An example of that arrangement is shown in FIG. 3.
Referring to FIG. 3, the distance measuring units 1 to 3 shown in
FIG. 1 are provided with output lines 31, 32 and 33 respectively.
The output of each of these units is arranged to be in the form of
an analog voltage which decreases accordingly as the distance
represented by the output is nearer. Distance information on the
nearest distance is obtained from one of the output lines by means
of diodes 34, 35 and 36 and a pull-up resistor 37. A window
comparator 39 is arranged to make the level of a signal line 40
high when a center measured distance value obtained through the
output line 32 is within a given range (indicating a medium
distance). Another window comparator 41 is arranged to make the
level of a signal line 43 high when a left measured distance value
obtained through the output line 31 is above a given value
(indicating a far distance) and to make the level of another signal
line 42 high when it is less than the given value (indicating a
near distance). A window comparator 44 is arranged to make the
level of a signal line 46 high when a right measured distance value
obtained through the output line 33 is above a given value
(indicating a far distance) and to make that of another signal line
45 high when it is less than the given value (indicating a near
distance). An AND gate 47 is arranged as follows: In a case where,
in respect to the above-stated "provided that" condition, the left
indicates a near distance, the center a medium distance and the
right a far distance, the AND gate 47 have all its inputs at high
levels. In that case, therefore, the AND gate 47 makes the level of
a signal line 48 high. An AND gate 49 is arranged as follows: In a
case where, in respect to the above-stated "provided that"
condition, the right indicates a near distance, the center a medium
distance and the left a far distance, the AND gate 49 have all its
inputs at high levels. In that case, therefore, the AND gate 49
makes the level of a signal line 50 high. An OR gate 51 is arranged
to make the level of a signal line 52 high in the event of the
above-stated "provided that" condition. An analog switch 53 is
arranged to output as lens driving information the center measured
distance value obtained through the output line 32, instead of the
nearest measured distance value obtained through a signal line 38,
in the event of the "provided that" condition."
The arrangement is simple as described above.
Each of the measured distance values is processed in the form of an
analog signal the level of which increases accordingly as the
measured distance is farther. However, the signal is not
proportional to the absolute distance (at zero for 0 m and at
infinity for an infinity distance) but is arranged to be reciprocal
with the absolute distance suited for AF (automatic focusing). In
other words, the signal is proportional to the depth of field.
Next, in cases where the criterional logic of the above-stated
"provided that" condition part is changed, the embodiment operates
as follows:
The nearest measured distance value is output as a general
rule;
"provided that" the center measured distance value is output in
cases where one of the left and right measured distance values
indicates a distance considerably nearer than the distance
indicated by the center measured distance value, where the center
measured distance value indicates a medium distance, and where the
other of the left and right measured distance values indicates a
distance considerably farther than the distance indicated by the
center measured distance value.
In other words, in respect to the above-stated logic, in a case
where the left and right measured distance values indicate values
in the opposite directions relative to the center measured distance
value, the mode of rewriting the conditions into relative values is
used for the logic.
FIG. 4 shows a case where the logic is digitally embodied in an
analog circuit. In FIG. 4, the parts having the same functions as
the corresponding parts of FIG. 3 are indicated by the same
reference numerals.
While the window comparators 44 and 41 of FIG. 3 are arranged to
make a discrimination between a far distance and a near distance,
this is changed according to the change in logic as follows in the
case of FIG. 4: A differential amplifier 61 is arranged to output
to a signal line 62 "the left measured distance value--the center
measured distance value". As a result, a signal of a considerably
low level flows to the signal line 62 when the left measured
distance value indicates a considerably nearer distance than the
center measured distance value. Then, a high level signal is
generated in a signal line 64 via a window comparator 63. Further,
in a case the left indicates a considerably farther distance than
the center, a signal of a considerably high level flows to the
signal line 62 to cause a high level signal to be generated in a
signal line 65 via the window comparator 63. Meanwhile, a
differential amplifier 66 is arranged to output and supply "the
right measured distance value--the center measured distance value"
to a signal line 67. As a result, a fairly low level signal flows
to the signal line 67 when the right measured distance value
indicates a considerably nearer distance than the center. Then, a
high level signal is generated in a signal line 69 via a window
comparator 68. When the right measured distance value indicates a
considerably farther distance than the center, a considerably high
level signal flows in the signal line 67 to cause a high level
signal to be generated in a signal line 70 via the window
comparator 68.
The ensuing processes of operation are similar to those of the
arrangement of FIG. 3. The AND gate 47 makes the level of the
signal line 48 high in cases where the level of the signal line 40
is high with the center measured distance value indicating a medium
distance, where the level of the signal line 70 is high with the
right measured distance value indicating a farther distance than
the center measured distance value, and where the level of the
signal line 64 is high with the left measured distance value
indicating a nearer distance than the center measured distance
value. Further, another AND gate 49 is arranged to make the level
of the signal line 50 high in cases where the level of the signal
line 40 is high with the center measured distance value indicating
a medium distance, where the level of the signal line 65 is high
with the left measured distance value indicating a farther distance
than the center measured distance value, and where the level of the
signal line 69 is high with the right measured distance value
indicating a nearer distance than the center measured distance
value. With the embodiment arranged in this manner, the center
measured distance value is selected and output as lens driving
information from the analog switch 53 as in the case of the
"provided that" conditions of the foregoing logic description.
With the distance difference included in the logic as described
above, the arrangement of FIG. 4, unlike that of FIGS. 2 and 3,
enables the device to make a discrimination without being
restricted by the fixed distance measuring zones. In other words,
it enables the device to correctly make a discrimination even in
cases where the center measured distance value indicates a nearer
distance or a farther distance than the medium distance. The
details of this will be described later.
The arrangement to take the distance difference into consideration
means consideration for a degree of blur that likely results from
focusing on one side. In other words, a great difference in
distance in the logic means that the use of one side for focusing
would result in a blurred picture of the other side. In selecting
one of the distance measuring points, this bears an important
meaning.
An example of an arrangement for an analog discrimination of the
"provided that" conditions of the logic described in the foregoing
is as shown in FIG. 5. Referring to FIG. 5, an output circuit 80 is
arranged to produce an output having a function which increases the
output when information indicating a medium distance is received
and decreases it when information indicating a near distance or a
far distance is received. As a result, a medium distance causes a
larger output to be produced into the signal line 40. An output
circuit 81 likewise has a function which is arranged to give a
larger output when its input is positive and large. When the right
measured distance value indicates a farther distance than the
center measured distance value, the output circuit 81 produces a
large output to a signal line 70. Another output circuit 82 has a
function which gives a larger output accordingly as its input is
negative and large. The output circuit 82 is thus arranged to
produce to a signal line 69 a large output which increases
accordingly as negative input increases. As a result, the signal
line 69 generates an output which increases accordingly as the
right measured distance value indicates a more nearer distance than
the center measured distance value. A function circuit 83 is
arranged in the same manner as the output circuit 82. Another
function circuit 84 is arranged in the same manner as the output
circuit 84.
The arrangement described above supplies the signal lines 40, 70,
69, 64 and 65 with signals similar to those of the digital
arrangement of FIG. 4.
An example of arrangement for obtaining an input-output
characteristic like that of the output circuit 81 is as follows:
Referring to FIG. 6 which shows the characteristic, the axis of
abscissa 91 shows an input (positive and large on the right-hand
side). The axis of ordinate 92 shows an output. In relation to the
input, the output value is produced at a function which is
represented by a straight line 93. When the input is less than a
value indicated by a point 94, the output value is zero. The output
is arranged to increase accordingly as the input increases from
this point 94. FIG. 7 shows by way of example a circuit arrangement
for obtaining this characteristic. Referring to FIG. 7, with an
input voltage applied to a signal line 95, a voltage of a value
corresponding to the above-stated point 94 is applied to a signal
line 96. Diodes 98 and 99 are arranged to transmit to a signal line
100 the higher one of the voltages applied to the signal lines 95
and 96. A differential amplifier 97 is arranged to produce a
voltage difference between the signal lines 100 and 96 to a signal
line 101. The signal line 101 thus carries information on a
difference between the value of the higher one of the signal levels
of the signal lines 95 and 96 and the level value of the signal
line 96. In other words, when the signal level of the signal line
95 is higher than that of the signal line 96, a difference by which
the former is higher than the latter is produced to the signal line
101. Further, this circuit arrangement can be changed into the same
arrangement as the above-stated output circuit 82 by arranging an
inversion circuit in front of the diode 99 on the signal line 95
and by arranging the voltage of the zero-crossing point of the
output circuit 82 to be applied to the signal line 96.
Again referring to FIG. 5, the circuit arrangement operates as
follows: Multipliers 110 and 111 are arranged to compute the "and"
parts of "provided that" conditions. A signal indicating the degree
of satisfying the "provided that" conditions by its level is
obtained at a signal line 113 from the outputs of the multipliers
110 and 111 which are output through signal lines 48 and 50 and
supplied to an adder 112. A comparator 114 receives this signal
makes a discrimination between satisfaction and nonsatisfaction of
the conditions in two values. This determines whether or not the
center measured distance value is to be selected by the analog
switch 53.
According to this method, the "provided that" conditions are
computed in an analog manner instead of a binary computation. This
permits synthetic judgment of the conditions. In other words, this
method has the following advantage: In a case where the center
measured distance value is somewhat deviating from a medium
distance, the center measured distance value is selected if the
left measured distance value indicates a very near distance and if
the right measured distance value an extremely far distance such as
an infinity distance. In an opposite case where the left and right
measured distance values are not indicating extremely far or near
distances, the center measured distance value does not have to be
selected. All elements of the above-stated "provided that"
conditions thus can be synthetically judged. In other words,
synthetic evaluation of each condition prevents a possible
misjudgment without setting a strict criterion for the "medium
distance". For example, even in cases where a judged medium
distance somewhat deviates from an ideal medium distance, a strong
influence of other conditions would give the same result as
mentioned above. This method is thus considered to allow a greater
latitude to the logic.
FIG. 8 shows a circuit arrangement for carrying out the computing
operation of the arrangement of FIG. 5 in a mode of "selecting a
measured distance value which is probably most correct". The
circuit arrangement thus makes selection by probability.
In the case of this embodiment, the logic of "selecting the nearest
one" is changed to a logic of "selecting a nearer distance at an
increased rate within a range from the infinity to 1 m and at a
lowered rate within a range nearer than 1 m". Further, a logic of
"selecting the center measured distance value when the left and
right measured distance values are larger than the center measured
distance value in the opposite directions" is changed to a logic of
"selecting the center measured distance value at an increased rate
when the left and right measured distant values are larger than the
center measured distance value in the opposite directions". The
arrangement of FIG. 8 then acts to "select one having a greater
rate of selection among the measured distance values".
In other words, the arrangement of FIG. 8 is based on the following
logic:
The rate where the left measured distance value is correct
increases accordingly as the left measured distance value is close
to 1 m;
The rate where the center measured distance value is correct
increases accordingly as the center measured distance value is
close to 1 m;
The rate where the right measured distance value is correct
increases accordingly as the right measured distance value is close
to 1 m;
The rate where the center measured distance value is correct
increases accordingly as the left measured distance value farther
than the center measured distance value and the right measured
distance value is nearer than the center measured distance value;
and
The rate where the center measured distance value is correct
increases accordingly as the right measured distance value is
farther than the center measured distance value and the left
measured distance value is nearer than the center measured distance
value.
The measured distance value to be selected is determined on the
basis of the above-stated logic according to the overall selectable
degrees of the three different measured distance values.
The circuit arrangement of FIG. 8 includes output circuits 120, 121
and 123, which are arranged to have such functions that cause them
to output to signal lines 123, 124 and 125 signals at higher levels
accordingly as the measured distance values are close to 1 m
respectively. The details of the arrangement of these output
circuits will be described later. The level of the signal line 123
is high if the left measured distance value is close to 1 m. As a
result, a large amount of current indicating "the rate of
correctness of the left measured distance value" flows to a signal
line 129 via a resistor 126. The level of the signal line 124
likewise is high if the center measured distance value is close to
1 m. As a result, a large amount of current indicating "the rate of
correctness of the center measured distance value" flows to a
signal line 130 via a resistor 127. The level of the signal line
125 is high if the right measured distance value is close to 1 m.
Then, a large amount of current indicating "the rate of correctness
of the right measured distance value" flows to a signal line 131
via a resistor 128.
Next, like in the case of FIG. 5, a distance difference between the
left and right measured distance values is used as follows: A
signal line 133 obtains information on the degree of a difference
between the left and right measured distance values from the output
circuits 81 and 83 via a multiplier 132 if the left measured
distance value indicates a near distance and if the right measured
distance value indicates a far distance. As a result a large amount
of current indicating "the rate of correctness of the center
measured distance value" flows via a resistor 134 to the signal
line 130. In cases where the right measured distance value
indicates a near distance and where the left measured distance
value indicates a far distance, information on the degree of
difference is obtained on the signal line 136 via an amplifier 135
from the output circuits 82 and 84. In this case, a current
indicating "the rate of correctness of the center measured distance
value" flows in a large amount to the signal line 130 via a
resistor 137.
Resistors 138, 139 and 140 are arranged to convert into voltage
values the added current values indicating "the rate of probable
correctness" obtained through the above-stated computing processes.
A peak detection circuit 141 is arranged to select the highest one
of the voltages obtained from the signal lines 129 to 131 and to
make high the level of one of signal lines 142, 144 and 146 which
correspond to the lines 129, 130 and 131. This circuit arrangement
will be described in detail later.
In a case where the left measured distance value is most probably a
correct value, the level of the signal line 142 becomes high. Then,
an analog switch 143 is turned on to allow the measured distance
value coming through the output line 31 to be output as lens
driving information. When the center measured distance value is
most probably the correct value, the level of the signal line 144
becomes high to turn on an analog switch 145. The switch 145 then
allows the measured distance value received from the output line 32
to be output as the lens driving information. If the right measured
distance value is most probably the correct value, the level of the
signal line 146 becomes high to turn on another analog switch 147.
The switch 147 then allows the measured distance value coming
through the output line 33 to be output as the lens driving
information.
The priority degrees thus can be given to the logic as in the case
of the above-stated "provided that" conditions by changing the
function provided within each of the output circuits 81 to 84 and
120 to 122 or by changing the value of each of the resistors 134,
137 and 126 to 128.
Each logic is thus synthetically judged by performing an adding
operation on the values of "the rate of correctness". This means
that a plurality of logic conditions are added up in an analog
manner. Therefore, each logic does not have to be independent of
others. The criterion for the logic also does not have to be
strict. In other words, the logic is acceptable even if it involves
some contradiction. It is an advantage that the logic conditions of
varied kinds can be added in a similar form.
The word "rate" as used in the foregoing description qualitatively
means probability. However, the word differs from probability in
the following points: Each of the logic conditions is independently
computed without checking the above-stated independency; and they
are arranged to be computable without normalization and even when
they include some graybody (ambiguity).
The input-output characteristic of the output circuit 120 of FIG. 8
is, for example, as described below:
FIG. 9 shows an example of the characteristic. The axis of abscissa
371 shows the input and the axis of ordinate 372 the output. In
relation to the input, the output is produced with functions as
represented by straight lines 373a and 373b. Up to a value of input
indicated by a point 374 (which is 1 m in the case of this
embodiment), the output gradually increases as shown by the
straight line 373a. In the event of input values above this
particular point, the output comes to gradually decrease from this
point 374 as shown by the straight line 372b. FIG. 10 shows a
circuit arrangement for attaining this characteristic. Referring to
FIG. 10, a signal line 359 is arranged to have an input applied
thereto while a voltage corresponding to the point 374 is applied
to signal lines 360 and 361. If the input value is less than the
value of the point 374, since the voltage corresponding to the
point 374 is applied to a signal line 360, by operations of an
adder 358 which has a given voltage applied to a signal line 362,
diodes 351 and 352, a differential amplifier 355, a diode 356 and a
signal line 362, an output is produced on a signal line 364 in a
manner as represented by the straight line 373a of FIG. 9. If the
value of the input to the signal line 359 is higher than the point
374, the voltage which corresponds to the point 374 and which is
applied to the signal line 361 causes diodes 353 and 354, a
differential amplifier 365, a diode 357 and the adder 358 to
produce an output as represented by the straight line 373b of FIG.
9.
FIG. 11 shows an example of arrangement of the peak detection
circuit 141 of FIG. 8. The level of an output line 154 becomes high
when an input coming via an input line 151 is at a maximum value.
The level of another output line 155 becomes high when an input
coming via an input line 152 is at a maximum value. The level of an
output line 156 becomes high when an input coming via an input line
153 is at a maximum value. In other words, when the input coming
via the input line 151 is at a maximum value, the output level of a
comparator 157 becomes high as the input via the input line 151 is
larger than the input coming via the input line 152. Then, the
output level of a comparator 158 also becomes high as the input via
the input line 151 is also larger than the input coming via the
input line 153. As a result, the output level of an AND gate 159
becomes high to make the level of the output line 154 high.
Further, when the input coming via the input line 153 is at its
maximum value, the input via the input line 153 is larger than the
input coming via the input line 151. This causes the output level
of a comparator 160 to become high. Then, since the input via the
input line 153 is larger than the input coming via the input line
152, the output level of a comparator 161 also becomes high. As a
result, the output level of an AND gate 162 become high to make the
level of the output line 156 high. In a case where the input coming
via the input line 152 is at a maximum value, the levels of the
comparators 157 and 161 and those of the AND gates 159 and 162 are
low. In this case, therefore, the output level of a NOR gate 163
becomes high to make the level of the output line 155 high.
FIG. 12 is a flow chart showing the operation of the analog circuit
of FIG. 8 to be performed with a microcomputer, etc. included in
the circuit arrangement. Referring to FIG. 12, the operation is as
follows:
At a step #21: For example, a register which is arranged to hold
each of the measured distance values is set in its initial
position. The flow of operation proceeds to a step #22. At the step
#22: The left, center and right measured distance values are
examined to see how much each of them differs from "1 m" which is
regarded as a near distance in this embodiment. Each of these
measured distance values is weighted according to the difference
(an absolute value) detected. The weighting degree increases
accordingly as the value is close to 1 m. The weighted values thus
obtained correspond to the outputs of the output circuits 120 to
122 of FIG. 8. The flow then proceeds to a step #23. At the step
#23: A check is made for a difference between the center measured
distance value and each of the left and right measured distance
values. The center measured distance value is weighted according to
degrees to which the left measured distance value is nearer than
the center measured distance value and the right measured distance
value is farther than the center measured distance value or
according to the degrees to which the right measured distance value
is nearer than the center measured distance value and the left
measured distance value is farther than the center measured
distance value. The weighted values corresponds to the outputs of
the multipliers 132 and 135 of FIG. 8. The flow proceeds to a step
#24. At the step #24: The measured distance value which is most
heavily weighted among the weighted measured distance values of the
left, center and right measured distance value is selected and
output as the current lens driving information, which corresponds
to the output of the peak detection circuit 141 of FIG. 8.
FIG. 13 shows an example of a program prepared for the flow of
operation shown in FIG. 12. The left, center and right measured
distance values are used as variables L, C and R respectively and
the "rate" mentioned in the foregoing is computed. As a result of
the computation, distance values are selected and output in the
form of variables OUT. In this example, the program is prepared in
a machine language something like the language called FORTRAN which
is employed in coding for a computer.
Referring to FIG. 13, the first letters "L", "C" and "R" in codes
LR, CR and RR respectively represent the left measured distance
value, the center measured distance value and the right measured
distance value. The letter "R" disposed in the second place in each
of these codes LR, CR and RR indicates the above-stated "rate of
probable correctness". Letters .alpha. and .beta. represent
weighting functions. The function .alpha. becomes a maximum value
when each of the left, center and right measured distance values is
1 m. The function beta increases the weighting degree accordingly
as the difference between the center measured distance value and
each of the left and right measured distance values increases
further than a difference value of 2 m. Further, a code ABS means
an absolute value. A code "max1" means selection of a maximum
value. Therefore, ABS (L-1 m) means to obtain the absolute value of
a difference obtained by subtracting 1 m from the left measured
distance value. The expression max1 ((L-C)-2 m, 0) means selection
of the larger one of "0" and a difference between 2 m and a
computed difference value between the left measured distance value
and the center measured distance value. Further "EQ" means
equal.
Referring to FIG. 13, the details of the program are as follows: At
a part corresponding to the step #21 of FIG. 12, an initial setting
action is of course performed on each of the variables. At a part
corresponding to the step #22, the left, center and right measured
distance values are respectively weighted according to their
differences from 1 m (by using the function .alpha.). They are thus
converted into the variables LR, CR and RR which respectively
include the rate of probable correctness. At a part corresponding
to the step #23: The center measured distance value which has
already been weighted by the function alpha is further weighted by
using the function .beta. to obtain the variable CR according to a
degree to which the left and right measured distance values differ
from the center measured distance value (with 2 m used as a datum
point in the case of the embodiment). At a part corresponding to
the step #24: One of the variables LR, CR and RR which is most
heavily weighted among them is selected. More specifically, if the
variable LR is equal to max1 (LR, CR, RR) is equal to each other,
the variable L which is the left measured distance value is output
as lens driving information.
To facilitate the program, a peak selecting action is changed into
a condition having the same value as the "max1".
Next, an arrangement for performing the operation of the
arrangement of FIG. 8 in a subtracting mode is described below with
reference to FIG. 14:
Referring to FIG. 14, the output of the output circuit 120 causes
the level of the signal line 123 to increase accordingly as the
left measured distance value is near to a given near distance.
However, an inverting amplifier 170 sucks currents out from the
signal lines 130 and 131 by means of resistors 171 and 172 in such
a way as to lower the rate of probable correctness of the center
and right measured distance values. The level of the signal line
124 likewise becomes higher accordingly as the center measured
distance value is close to the given near distance. However, an
inverting amplifier 173 sucks currents out from the signal lines
129 and 131 by means of resistors 174 and 175 in such a way as to
lower the rate of probable correctness of the left and right
measured distance values. The level of the signal line 125 also
increases accordingly as the right measured distance value is near
to the given near distance. However, an inverting amplifier 176
sucks currents out from the signal lines 129 and 130 by means of
resistors 177 and 178 in such a way as to lower the rate of
probable correctness of the center and left measured distance
values.
Further, when the output of the signal line 136 indicates that the
left measured distance value is farther than the center measured
distance value and the right measured distance value is nearer than
the center measured distance value, an inverting amplifier 179
causes resistors 180 and 181 to suck out currents from the signal
lines 129 and 131 which carry signals indicating the rates of the
left and right measured distance values. In cases where the output
of the signal line 133 indicates the right measured distance value
is farther than the center measured distance value while the left
measured distance value is nearer than the center measured distance
value, an inverting amplifier 182 causes resistors 183 and 184 to
suck currents out from signal lines 129 and 131 which carry signals
indicating the rates of the left and right measured distance
values.
As apparent from the above description of the arrangement of FIG.
14, the use of the current sucking subtraction mode in combination
with the adding mode shown in FIG. 8 enables the device to perform
about the same functions. Besides, the arrangement of FIG. 14
prevents the values (voltage values) from becoming excessively
large in computing and obtaining a total of them.
FIG. 15 shows another embodiment, which is arranged as follows: In
the arrangements of FIGS. 8 and 14, the "rate of probable
correctness" is obtained from one of the signal lines carrying a
signal of the "rate of probable correctness" by performing an
adding or subtracting operation. In the case of FIG. 15, however,
the "rate" is obtained by performing an adding operation by using a
plurality of signal lines.
For example, three signal lines for 0%, 50% and 100% are used in
the following manner:
In the case of a strongly negative result of logic: A given value
is added to the 0% signal line.
In the case of a weakly negative result of logic (rather negative):
The given value is added to the 0% and 50% signal lines.
In the case of an indecisive result of logic: The given value is
added to the 50% signal line.
In the case of a weakly affirmative result of logic: The given
value is added to the 50% and 100% signal lines.
In the case of a strongly affirmative result of logic: The given
value is added to the 100% signal line.
In making an overall judgment, the barycenter positions (%) of the
three signal lines are obtained from the values obtained in the
above-stated manner and then the line having the largest value of
the barycenter position is selected.
Compared with the mode described in the foregoing, the above-stated
mode of computation requires a greater number of computing
processes. However, in the modes described in the foregoing, since
the synthesization (or integration) of logic is carried out by one
of the signal lines, the affirmative and negative degrees are
synthesized. In other words, these modes are incapable of
discriminating the "rate of probable correctness" obtained in the
event of a plurality of indecisive results of logic from the "rate
of probable correctness" obtained without any indecisive result of
logic. Therefore, an ambiguous (gray) result of logic might be
selected by mistake. Whereas, in the mode of FIG. 15, the "rate" of
the 50% signal lines increases in the event of many indecisive
results of logic. Then, in carrying out the barycenter computation,
"0%" negative or "100%" affirmative becomes "25%" or "75%." In
other words, the negative and the affirmative are computed in a
thinned state. It is, therefore, an advantage of this mode that the
computing operation is carried out including the above-stated
indecisive and weak affirmative results and a weak negative
result.
This mode can be extended into the so-called "Fuzzy theory" which
has recently become popular.
In the arrangement of FIG. 15, the single signal line of "the rate
of probable correctness" used in the arrangement of FIG. 8 is
replaced with five signal lines including 0%, 25%, 50%, 75% and
100% signal lines.
The level of the signal lines 123 becomes higher and the output
level of an amplifier 200 increases accordingly as the left
measured distance value is near to the near distance. The resistor
126 which is singly disposed in the signal line 123 in the case of
FIG. 8 is replaced with a resistor block 201. The resistor block
201 consists of five resistors of five different resistance values
which are connected to five signal lines for five different "rates
of likely correctness", including: A 100% signal line arranged to
have a large current with a small resistance and a 0% signal line
arranged to have a small current with a large resistance.
Information about the degree of likeliness as to whether the center
measured distance value is the near distance is likewise supplied
via an amplifier 202 to a resistor block 203 including five signal
lines provided for determining the rate of the center measured
distance value. Information about the degree of likeliness as to
whether the right measured distance value is the near distance is
also supplied via an amplifier 204 to a resistor block 205
including signal lines provided for determining the rate of the
right measured distance value.
The resistance difference among the above-stated resistor blocks
is, so to speak, a "ratio" between one way of thinking that "the
left measured distance value is absolutely correct and should be
selected" and another way of thinking that, although it is
logically correct, "there is a possibility that a measured distance
value other than the left measured distance value might be correct,
that is, the left measured distance value might be not selected" in
a case where the left measured distance value is, for example,
logically determined to be the near distance. Therefore, the
internal resistance ratios of resistor blocks 206 and 401 which are
provided for supplying currents from signal lines 133 and 136 to
the five signal lines arranged to determine the rate of the center
measured distance value may, in some cases, differ from those of
the resistance ratios of other resistor blocks 201, 203 and 205.
Especially, as mentioned in the foregoing, the priority logic
arrangement of "provided that ---" conditions results in a lower
resistance on the 100% side and a higher resistance on the 0% side.
Further, the average internal resistance value of each resistor
block is arranged to be low in the case of a strong logic depending
on the strength of the whole logic, i.e. according to the weight of
the result of logic.
The signal line groups provided of three kinds carrying information
on different rates to be selected are arranged to supply
information on the rates to be selected to signal lines 208, 209
and 210 through barycenter computing units 207 which are arranged
to compute applicable barycenters respectively. The peak detection
circuit 141 is arranged to obtain the highest selectable rate of
the left, center and right measured distance values. The level of
one of the signal lines 142, 144 and 146 then becomes high to cause
the output of the peak detection circuit 141 to be output as lens
driving information from one of the analog switches 143, 145 and
147.
FIG. 16 shows by way of example the details of each of the
above-stated barycenter computing unit 207.
The signal lines for the selective rates of 0 to 100% (five signal
lines for 0%, 25%, 50%, 75% and 100% in this specific case) are
connected to a resistor 221 in positions from the left to the right
in order of rate. As a result, a current is divided and shunted to
signal lines 222 and 223 in a ratio according to the connecting
positions of the five signal lines. The shunted currents are
supplied to a divider 224, which is arranged to produce an output
according to the dividing ratio between the input currents. The
output of the divider 224 is supplied to a signal line 225 in the
form of a voltage. Such being the arrangement, 100 parts of voltage
is produced to the line 225, for example, if the current is flowing
only to the position of 100%, and 50 parts of voltage is produced
if the current is flowing only to the position of 50%. This
arrangement enables the unit 207 to give a signal for the "rate to
be selected" on the basis of the synthetic logic. .Iadd.The
selecting operation can be called a defuzzifying operation and unit
207 can be called a defuzzifier operation circuit..Iaddend.
With a plurality of signal lines for 0 to 100% provided as
mentioned above, even such a measured distance value that has a
gray result of logic can be computed. This is an advantage in case
where the rates are to be influenced by varied number of logics. In
other words, the arrangement to have the plurality of signal lines
is advantageous, for example, in cases where one logic is used for
determining the rate of each of the left and right measured
distance values and three logics for that of the center measured
distance value like in the case of the preceding example described
in the foregoing, because: For an accurate computation of
probability, the result of computation must be normalized for each
logic. In the case of the example described above, the probability
of the center must be increased by affirmation, decreased by
ambiguity and decreased by denial while those of others must be
decreased and increased accordingly (although it depends also on
the involutional relation of logic). In the case of the ambiguous
logic, the decrease and increase must be different from the
increase and decrease under affirmative and negative conditions. In
short, the accuracy of computation cannot be maintained without
accurate and complex operations on the probability of the cases
according to the logical results (especially in the event of many
cases and many gray logics).
In the above-stated example, the provision of, for example, the 50%
signal line enables the device to thin down the degrees of
affirmation and denial for each of the rates. Further, as regards
affirmation or denial of each rate, a distribution constant having
some value in the 50% signal line permits normalization of
distributed values through comparison of the barycenters of
them.
FIG. 17 is a flow chart showing the operation of the above-stated
arrangement of FIG. 15 with a microcomputer, etc. included therein.
Referring to FIG. 17, the operation is as follows: At a step #31:
Initial setting is performed. At a step #32: The left, center and
right measured distance values are checked for their differences
from "1 m" which is considered to be a standard near distance. Each
of them is weighted within its array (of signal lines) according to
the difference thus found (by the resistor blocks 210, 203 and 205
of FIG. 15). At a step #33: With importance attached to the
difference of the center measured distance value from the left and
right measured distance values, the center measured distance value
is weighted within its array (the resistor blocks 206 and 401 of
FIG. 15) according to degrees to which the left measured distance
value is nearer and the right measured distance value is farther
than the center measured distance value, or the right measured
distance value is farther and the left measured distance value is
nearer than the center measured distance value. .Iadd.Such degrees
can be called fitting degrees. .Iaddend.Then, the flow proceeds to
a step #34. At the step #34: The barycenters of the weighted left,
center and right measured distance values are obtained from within
their arrays respectively. At a step #35: The measured distance
value having the largest barycenter (.Iadd.center of gravity)
.Iaddend.is selected and output (the output of the peak detection
circuit 141 of FIG. 15).
FIG. 18 shows an example of a program prepared for the flow of
operation shown in FIG. 17. In this case, the array of the 0 to
100% signal lines is expressed as an array 0 to 100 indexes ($) for
computation. Further, the functions of the resistor blocks 210,
203, 205, 206 and 401 are expressed as the arrays of .alpha.$ and
.beta.$.
Referring to FIG. 18, the details of the program are as follows: At
a part corresponding to the step #31 of FIG. 17, initial setting of
all variables is performed. At a part corresponding to the step
#32: The left, center and right measured distance values are
weighted within their arrays (by a multiplying operation with the
function .alpha. for 0 to 100). They are thus converted into
variables LR, CR and RR which respectively include the "rate of
probable correctness". At a part corresponding to the step #33:
According to the degrees to which the left and right measured
distance values deviate in different directions, weight is further
attached to the center measured distance value within its array (by
a multiplying operation with the function .beta. for 0 to 100). The
center measured distance value is thus made into the variable CR.
At a part corresponding to the step #34: The barycenters of the
added left, center and right measured distance values which are
weighted for 0 to 100 are obtained from within their arrays
respectively. At a part corresponding to the step #35: The valve
having the largest barycenter is selected and output.
FIG. 19 shows a circuit arrangement based on a higher notion than
the arrangement of FIG. 15. Referring to FIG. 19, output circuits
230 have functions for "outputting a larger value accordingly as
the measured distance value is close to 1 m" like in the case of
the output circuits 120 to 122 of FIG. 15. The circuits 230 are
thus arranged to output via signal lines 231 to 233 such signals
that indicate degrees to which the left, center and right measured
distance values are close to 1 m respectively. An output circuit
234 has a function for varying the rate according to the degrees of
the measured distance values. The circuit 234 corresponds to the
resistor blocks 201, 203 and 205 of FIG. 15. Function circuits 235
to 237 which correspond to the amplifiers 200, 202 and 204 of FIG.
15 are arranged to multiply the degree outputs by the function
output of the circuit 234. A computer 238 which is arranged to add
to the current rate a rate change obtained as a result of logic.
This computing operation corresponds to the operation of adding
currents by the resistor blocks of FIG. 15. Output circuits 239
have functions for "outputting a larger value accordingly as the
measured distance value is farther than the center measured
distance value" like in the case of the output circuits 82 and 83
of FIG. 15. Multipliers 241 are arranged to perform multiplying
actions corresponding to the "and" included in the same logic
conditions as those of the multipliers 132 and 135 of FIG. 15. An
output circuit 242 has a function for changing the rate on the
basis of the same logic as that of the resistor blocks 206 and 401
of FIG. 15. A computer 243 is arranged to multiply the degree
outputs of the circuits 241 by the function output of the circuit
242. A computer 245 is arranged to change the value of rate with
the output of the computer 243.
The ensuing operation of the arrangement of FIG. 19 is similar to
that of the arrangement of FIG. 15 and one of the measured distance
value is eventually output as lens driving information.
Again referring to FIG. 19, the arrangement is described according
to the Fuzzy theory as follows: The output circuits 230, 239 and
240 correspond to condition membership functions in the Fuzzy
rules. .Iadd.Such condition membership functions can also be called
if-part membership functions. .Iaddend.The output circuits 234 and
242 are consequent membership functions. .Iadd.Such consequent
membership functions can also be called then-part membership
functions. .Iaddend.In the above-stated arrangement, the computing
operations of the computers 235, 236, 237, 243 and 244 are
performed in accordance with the method of Larsen to obtain the
consequent membership functions from the condition membership
functions. .Iadd.Computers 235, 236, 237, 243 and 244 can be called
Fuzzy computers or Fuzzy operation circuits. .Iaddend.The
convolution of rules performed by the computers 238 and 245
corresponds to computation of an algebraic sum. (While a simple
adding operation is performed by the arrangement described, a
maximum value "1" must be computed, in theory.) Further, an
algebraic product is used for the composition of conditions
performed by the multiplier 241.
Other effective methods include, for example, the method listed
below (an excerpt from a thesis of Mr. Mizumoto of Osaka Electric
Communication College, disclosed at the 5th Knowledge Engineering
Symposium):
______________________________________ Product obtaining operation:
Logical product: X Y = min (X, Y) Algebraic product: X .multidot. Y
= X * Y Bounded product: X .multidot. Y = max (0, (X + Y - 1))
Drastic product: X Y = X * Y (when X = 1 or Y = 1) 0 (when X
.noteq. 1 and Y .noteq. 1) Sum obtaining operation: Logical sum: X
Y = max (X, Y) Algebraic sum: X Y = X + Y - X * Y Bounded sum: X
.sym. Y = min (1, (X + Y)) Drastic sum: X Y = X + Y (when X = 0 or
Y = 0) 0 (when X .noteq. 0 and Y .noteq. 0)
______________________________________
The computing operation methods for obtaining consequent membership
functions from the condition membership functions, include a method
of using sum obtaining operation in composing (combining) rules,
i.e. a method of adding rates of probable correctness (adding "0"
if totally unknown), which are as shown below: ##EQU1##
Further, there are methods of using a product obtaining operation
in composing (combining) rules. This is based on the following
concept: In the event of a totally unknown part, "1" is used. The
number of unknown parts decreases accordingly as conditions are
established to give the consequent membership functions. The
methods based on this concept includes: ##EQU2##
FIG. 20 is a flow chart showing the operation of the arrangement of
FIG. 19 with a microcomputer, etc. included in the arrangement.
Referring to FIG. 20, the flow of operation is as follows At a step
#41: Weight is attached to each of the left, center and right
measured distance values according to degrees to which they are
deviating from 1 m. At a next step #42: The center measured
distance value is weighted according to degrees to which the left
and right measured distance values are deviating from the center
measured distance value. At a step #43: Among these measured
distance values, the most heavily weighted value is selected and
output.
FIG. 21 describes the flow of operation of FIG. 20 according to the
Fuzzy theory. In FIG. 21, a term "near distance" means the distance
of 1 m as mentioned in the foregoing and is a function which takes
a maximum value of "1". A function .alpha. gradually takes "0 to 1"
for 0 to 100%. A function .beta. somewhat acutely takes, for
example, 0 to 1 for 50 to 100%. The strengths of two logics are
differentiated from each other by a difference between the
functions .alpha. and .beta..
The details of the operation of FIG. 21 are as follows: At a part
corresponding to the step #41: The left, center and right measured
distance values are respectively weighted according to the degrees
to which they are close to the near distance 1 m. Then the rate of
probable correctness of each measured distance value is computed
with the function .alpha. to obtain variables LR, CR and RR. At a
step corresponding to the step #42: Weight is further attached to
the center measured distance value according to the degree to which
the difference of the center measured distance value from the left
and right measured distance values is large and positive (i.e. the
degrees to which the left and right measured distance values
deviate from the center measured distance value, or relative
relations of the left, center and right measured distance values in
respect to far (near), medium, and near (far) distances. Then, the
rate of probable correctness of the weighted center measured
distance value is computed with the function .beta. to obtain the
variable CR. At a part corresponding to the step #43: Among the
weighted variables LR, CR and RR, the most heavily weighted one is
selected and output.
In all the examples described, one of the distance values obtained
from the left, center and right distance measuring areas is
selected as a result of distance measurement. In the following,
however, a method of employing an intermediate value between these
measured distance values as the result of distance measurement:
FIG. 22 shows an arrangement for carrying out this method. This
arrangement is described as a modification of the analog computing
arrangement of FIG. 5.
The use of the signal line 113 for the center measured distance
value gives a signal showing a better rate. Therefore, a value
between the center measured distance value and a distance value
nearest thereto is produced in an analog manner according to the
result obtained from the signal line 113. A variable resistor 260
is provided for this purpose. The resistor 260 is arranged to
select the nearest measured distance value obtained from the signal
line 38 when the level of the signal line 113 is zero and to select
the center measured distance value obtained from the output line 32
when the signal line 113 is at a maximum level. The variable
resistor 260 thus operates in a servo-like manner according to the
level of the signal line 113. When the signal line 113 is at a
medium level, the resistor 260 produces an intermediate distance
value between the nearest distance value and the center measured
distance value.
The selection of an intermediate value in this manner might bring
both distance measuring concerned out of focus in the event of
shallow depth of field. However, ordinary photographing operations
generally have a certain depth of field to give a good picture with
both areas in focus.
FIG. 23 shows a circuit arrangement which is a modification of the
arrangements of FIGS. 8 and 14 and is arranged to output an
intermediate value. Referring to FIG. 23, the processes of
operation up to the computation of the rates of the signal lines
129, 130 and 131 are about the same as in the preceding example.
This arrangement includes a normalizing circuit 261, which is
arranged to normalize the signals of three rates and to output the
normalized signals to three signal lines 262, 263 and 264, in such
a way as to make the total of these three rates into "1".
Multipliers 265, 266 and 267 are arranged to multiply the measured
distance values by these three normalized signals. The outputs of
the multipliers 265, 266 and 267 are supplied to an adder 268 to
obtain a weighted average of the measured distance values. The
weighted average value is output as lens driving information. The
arrangement thus makes a synthetic or integral judgment on the
three measured distance values to give a picture which is in focus
all over.
FIG. 24 shows by way of example the details of the above-stated
normalizing circuit 261 of FIG. 23. Reference numerals 271, 272 and
273 denote positive rate signals. Multipliers 274, 275 and 276
multiply these rate signals by the signal of a signal line 280. The
results of the multiplying actions are output to signal lines 277,
278 and 279. The three signals thus obtained are added together
through resistors 281, 282 and 283. An inverting amplifier 284 is
arranged to control the signal line 280 in such a way as to make
the sum of these three signals into "1".
FIG. 25 shows a circuit arrangement which is arranged to output an
intermediate value in computing the distribution probability in a
manner as shown in FIG. 15. The circuit parts up to the part 210
are identical with those of FIG. 15. Parts 261 to 268 are arranged
to obtain a weighted average value in the same manner as in the
case of FIG. 23.
The arrangement to obtain a weighted average after completion of
rate computation as in the cases of FIGS. 23 and 25 enables the
device to give a correct output with the three values selected
through the complex computing operation irrespectively of
variations taking place in the rates of the three values.
The arrangements described in the foregoing eliminate the adverse
effects of nearby obstacles such as the ground, etc. by means of
the measured distance values and information on differences between
them. However, information of other kinds are also usable as means
for making an effective discrimination.
An example of arrangement for making the discrimination by means of
a measured light value (brightness) is as follows: FIG. 26 shows by
way of example the arrangement of a light measuring sensor of a
camera. The illustration includes a camera body 300; and distance
measuring units 1, 2 and 3 which are also shown in FIG. 1. The
units 1, 2 and 3 are arranged to measure distances in the
directions 301, 302 and 303 respectively. Known light measuring
units 304, 305 and 306 are arranged to measure light also in the
directions 301, 302 and 303.
FIG. 27 shows a photographing frame of the camera in relation to
the distance and light measuring directions. The measuring
directions 301, 302 and 303 are arranged to be not only laterally
spreading as shown but also vertically spreading relative to a
photographing picture plane 307, because: In some cases, framing
requires to have the picture plane in a vertical posture as shown
in FIG. 28. The spreading arrangement of measuring directions then
permits distance measurement in the lateral directions with the
picture plane in the vertical posture.
For an improved degree of accuracy, the number of measuring points
may be increased from three points to five or more points as shown
in FIG. 28. However, the increase of measuring points is not easy
in terms of cost and, therefore, should be determined according to
the purpose for which the camera is designed. Meanwhile, the
discrimination of a nearby obstacle such as the ground from other
objects is necessary in all cases. In view of this, the following
description is given on the assumption that the number of measuring
points is three.
FIG. 30 shows by way of example the arrangement of the above-stated
embodiment. In this case, the camera is controlled by measuring
distances and brightness in three directions. An average light
measuring unit 308 is arranged to obtain the average of three
measured light values received from the light measuring units 304,
305 and 306. The average value is output to a signal line 309. A
computing circuit 310 is arranged to selectively output a measured
distance value as lens driving information. Compared with the
arrangements described in the foregoing, the computing circuit 310
receives a greater number of inputs including the above-stated
three measured light values and the average measured light value of
the signal line 309 in addition to measured distance values.
FIG. 31 is a flow chart showing the operation of the above-stated
embodiment with a microcomputer, etc. included in the arrangement
described. Referring to FIG. 31, the operation is as follows: At a
step #51: The left, center and right measured distance values are
weighted according to degrees to which they deviate from 1 m. At a
step #52: The center measured distance value weighted according to
degrees to which the left and right measured distance values differ
from the center measured distance value. At a step #53: If one of
the left and right measured distance values indicates a near
distance and if the brightness of the other side is high, the one
measured distance value is weighted according to the degree of
brightness of the other side, because: In a case where one side is
at a near distance and the brightness obtained in the direction of
the opposite side is higher than an average degree of brightness,
there is a high degree of possibility that the opposite side might
be directed to a sky while the above-stated one side is directed to
the ground. At a step #54: Among the weighted measured distance
values, the value most heavily weighted is selected and output.
FIG. 32 is a description of the flow of FIG. 31 in accordance with
the Fuzzy theory. The parts of the description corresponding to the
steps #51, #52 and #54 of FIG. 31 are the same as the steps #41,
#42 and #43 of FIG. 21. The details of these parts are omitted. A
part corresponding to the step #53 is as follows: For example, with
the weighted right measured distance value as it is close to the
near distance, if the left measured light value is brighter than an
average brightness, the weighted value of the variable RR is
reduced by the use of a function .gamma..
FIG. 33 shows by way of example consequent membership functions
indicated by .alpha., .beta. and .gamma.. Referring to FIG. 33, the
function indicated by .beta. is a function which is near to 100%
representing "a considerably high degree of likeliness" and is used
for removing the influence of the ground from the distance
difference. The function indicated by .gamma. is a nearly flat
function which indicates a weak denial "somewhat unlikely" and is
used for the purpose of removing something like the ground from the
brightness. The computing circuit 310 of FIG. 30 acts according to
the above-stated concept to selectively output information on a
measured distance to a likely main object and supplies it to a
signal line 311 for causing an AF driving (automatic focus
adjustment) system 5 to adjust the focal point of the lens.
Further, by this action, the left, center and right measuring areas
are checked to find which of them is indicating a likely main
object. The circuit 310 outputs to another signal 312 one of the
left, center and right measured light values which is obtained from
the direction of the likely main object by a selecting arrangement
similar to the distance selecting arrangement. A comparator 313 is
arranged to compare the measured light value obtained from the
direction of the likely main object with an average measured light
value. If the former is much darker than the latter, the comparator
313 produces a high level signal indicating a possible
back-lighting condition. A flash-device discriminating unit 315 is
arranged in a known manner to cause a flash device 317 to flash by
outputting a high level signal to a signal line 316 in the event of
a back-lighting or dark condition. Under other conditions, the unit
315 instructs, through a signal line 318, a diaphragm driving
system 319 to obtain an apposite aperture value according to the
automatic light measurement. Further, an analog switch 320 is
arranged to control the diaphragm driving system 319 to make its
action commensurate with the flash device 317 when the flash device
317 is to be operated. The arrangement enables the camera to
correctly perform distance and light measuring operations even when
the main object is located in a part other than the center of the
picture plane or when the object is under a back-lighting
condition.
While the brightness of the object is utilized in the arrangement
described above, an example where an input other than brightness is
described below:
FIGS. 34 and 35 are illustrations provided for description of a
further embodiment. FIG. 34 shows the camera as in a state of being
held sidewise. The camera 330 is held by one hand 331. A release
button 332 is used for photographing in this posture. FIG. 35 shows
the camera as in a state of being held longwise. The camera can be
gripped likewise. Another release button 333 which is provided for
use in this instance facilitates a release operation.
The use of the release button 333, therefore, means vertical
photographing. In this case, there is a strong possibility of
measuring the ground with the left distance measuring point as
indicated by the reference numeral 301 of FIG. 28. In other cases,
it is highly possible that the right distance measuring point is
measuring the ground as indicated by the numeral 303 of FIG. 27. A
signal SW1 indicating the use of this release button 333 is
arranged to be supplied via a signal line 334 of FIG. 30 to the
computing circuit 310 for selection of the distance measuring
point.
FIG. 36 is a flow chart showing the operation of the computing
circuit 310 performed with a microcomputer, etc. included therein
for a discrimination between the use or nonuse of the release
button 333 for photographing. The flow of operation is as follows:
At a step #61: Each of the left, center and right measured distance
values is weighted according to how much the value differ from 1 m.
At a next step #62: The center measured distance value is weighted
according to the degrees to which the left and right measured
distance values are deviating from that of the center measured
distance value. At a step #63: If the measured distance value of
one side indicates a near distance, the value of that side is
weighted according to whether the camera is in the vertical
photographing posture. The reason for this step: If one side
indicates a near distance in the event of the vertical
photographing, that side is probably measuring a distance to the
ground. Therefore, value of that side is weighted on the basis of
this possibility. At a step #64: Among the weighted measured
distance values, the most heavily weighted distance value is
selected and output.
FIG. 37 shows a description of the flow of FIG. 36 according to the
Fuzzy theory. At parts corresponding to the steps #61, #62 and #64
are similar to the steps #41, #42 and #43 of FIG. 21 and thus
require no detailed description. At a part corresponding to the
step #63: Even when the right measured distance value, for example,
is heavily weighted on account of its closeness to the near
distance, the weight attached by the variable RR is reduced by the
function .gamma., on the basis of the above-stated inference, if
the camera is then in the vertical photographing posture.
FIG. 38 shows an example wherein a different arrangement is used in
making a discrimination between a normal vertical posture and
inversely vertical posture. Referring to FIG. 38, a disc 335 is
arranged to rotate on a shaft 336. A weight 337 is provided at a
part of the rotary disc and is arranged to be in a lower position.
A non-contact type encoder 338 is secured to the camera. The
posture of the camera is detectable by reading the code of a code
disc 339 which is coaxial with the disc 335. Posture information
ANG from the encoder 338 is supplied via a signal line 340 to the
computing circuit 310 of FIG. 30. This enables the device to
correctly detect "the direction of the likely ground", even in the
event of the inversely vertical posture, without recourse to the
use of an operation member like in the case of the preceding
example.
FIG. 39 is a flow chart showing the operation of the above-stated
computing circuit 310 to be performed with angle signals and with a
microcomputer, etc. included in the circuit 310. The flow of
operation is as follows: At a step #71: Each of the left, center
and right measured distance values is weighted according to how
much it differs from 1 m. At a step #72: The center measured
distance value is weighted according to degrees to which the left
and right measured distance values differ from the center measured
distance value. At a step #73: In a case where the measured
distance value of one side indicates a near distance, this value is
weighted according to the photographing posture of the camera. This
step is provided for weighting according to whether or not the
camera is in the vertical posture according to the same inference
as mentioned in the preceding embodiment. At a step #74: Among the
measured distance values, the most heavily weighted value is
selected and output.
FIG. 40 is a description of the flow of FIG. 39 according to the
Fuzzy theory. Parts corresponding to the steps #71, #72 and #74 are
similar to the steps #41, #42 and #43 of FIG. 21 and thus no
further description of them is required here. A part corresponding
to the step #63: In a case where the right measured distance value,
for example, is weighted as it indicates a near distance, if the
right distance measuring direction is lower than the left distance
measuring direction, the weight attached by the variable RR is
reduced by means of the function .gamma. according to the same
inference as mentioned in the foregoing. In other words, the
possibility of the ground is determined by two rules according to
binary information about which of the left and right sides is lower
than the other.
Further, an obstacle which is most likely the ground can be
likewise eliminated in the case of measuring distances in five
directions like in the case of FIG. 29.
Next, an example of using a somewhat different kind of information
based on the Fuzzy theory in selecting a measured distance value is
described below:
Again referring to the arrangement of FIG. 30, for the measured
distance selection to be made by the computing circuit 310, the
information ST about the use or nonuse of the flash device is added
via the signal line 316 to the inputs of the circuit 310. The
distance selecting logic can be changed on the basis of this
additional input. The output of the flash device 317 is limited. If
the object to be photographed is located at a far distance from the
camera, the object cannot be adequately photographed as the
photographable distance is limited to a medium distance because of
insufficient quantity of light. Therefore, for a photograph, the
lens is preferably focused for a range up to a distance reachable
by the flash light (reachable distance).
FIG. 41 is a flow chart showing the operation of the computing
circuit 310 performed on the basis of the above-stated concept with
a microcomputer, etc. included in the computing circuit 310. The
flow of operation is as follows: At a step #81: Each of the left,
center and right measured distance values is weighted according to
degrees to which the measured value deviates from 1 m. At a step
#82: The center measured distance value is weighted according to
degrees to which the left and right measured distance values differ
from that of the center measured distance value. At a step #83:
Each of the measured distance values is weighted according to
whether the distance is reachable by the flash light. The reason
for this step is as follows: As mentioned in the foregoing, the
lens is preferably focused within the range of distances reachable
by the flash light. Therefore, weight is attached according to the
reachable distance. At a step #84: Among the measured distance
values, the most heavily weighted value is selected and output.
FIG. 42 shows a description of the flow of FIG. 41 based on the
Fuzzy theory. Parts corresponding to the steps #81, #82 and #84 of
FIG. 41 are similar to the steps #41, #42 and #43 of FIG. 21 and,
therefore, the details of them are omitted from the following
description. At a part corresponding to the step #83: The weight
attached to, for example, the right measured distance value and
computed according to whether the measured value is close to the
near distance is increased by a function .delta. accordingly as the
right measured distance value is closer to the flash light
reachable distance.
The term "reachable distance" as used above is a membership
function which becomes zero at a distance exceeding 5 m as shown in
FIG. 43. The consequent .delta. is preferably a membership function
which indicates a weak affirmation as shown in FIG. 44.
A remote-control receiving signal Rem which is to be supplied via a
signal line 350 as shown in FIG. 30 is under a condition similar to
the above-stated condition. Some cameras are arranged to have the
shutter releasable by means of a remote-control device like in the
case of a TV receiver. Like the flash device 317, the
remote-control device has a limited reachable distance. Therefore,
it is highly possible that the object is located within the
reachable distance when an instruction is received. The flow of
operation, therefore, can be executed in about the same manner with
the part "flash device is lighted" of the description of FIG. 42
replaced with "remote-control signal is received".
FIG. 45 shows another example of the membership function of the
reachable distance obtained when the remote-control device is used.
The remote-control device is usually used at a distance between 1 m
and 5 m or thereabout. Therefore, the fact that the use of the
remote-control device at a distance less than 1 m is abnormal would
serve to prevent a faulty operation at a distance less than 1
m.
Therefore, a parameter for "frequently used distance" can be
included in this manner as desired.
An example wherein information of another kind according to the
Fuzzy theory is described as follows:
In each of the foregoing examples, the membership function for a
distance difference from the center measured distance value which
is output from the output circuit 239 of FIG. 19 is arranged to
increase accordingly as the difference is greater than a difference
of 2 m as shown in FIG. 46. In actual evaluation, however, if the
aperture is small or if the focal length of the phototaking lens is
small to give a deep depth of filed, a difference by 2 m or
thereabout makes no difference in focusing. Under such a condition,
the difference might remain inconspicuous until the difference
exceeds 3 m.
Therefore, the membership function for the above-stated distance
difference is preferably switched to a state of being insensitive
to the distance difference, as shown in FIG. 47, in selecting the
measured distance at the computing circuit 310 of FIG. 30, in a
case where the membership function is stopped down further than F8
or the focal length is less than 50 mm according to an aperture
signal AV received through a signal line 309 or focal length
information f received through a signal line 360. Further,
conversely, the membership function is preferably switched to a
state of being sensitive to the distance difference as shown in
FIG. 48 in the event of in aperture which is not much stopped down
or in the event of a long focal length of the lens.
The above-stated concept can be simply carried out by replacing one
membership function with another according to the above-stated
conditions.
In another method for carrying out the above-stated concept,
distance differences are multiplied by a value "focal length X
aperture value" to make their blurring degrees on the film equal to
each other before introducing them into the membership function.
This method is more easily introducible for the general logic.
The introduction of this relation according to the Fuzzy theory is
made in the following manner:
As shown in FIG. 50, two channels of inference formulas are
prepared according to the longness or shortness of the focal
length. Then, membership functions are prepared as shown in FIG. 46
for "positive and large" and as shown in FIG. 48 for "positive and
extra-large". A reference numeral 361 of FIG. 51 denotes a function
which becomes "1" at the maximum focal length in the case of a
"long" focal length. A numeral 362 of FIG. 51 denotes a function
which becomes "1" at the minimum local length in the case of a
"short" focal length. A numeral 363 of FIG. 52 denotes a
trapezoidal function which is provided for the "full aperture" side
of the aperture and becomes "1" at aperture values located on the
full aperture side of a certain aperture value. A numeral 364 of
FIG. 52 denotes a trapezoidal function which is provided for the
"stopped-down" side of the aperture.
The preparation of functions in two channels for the conditions of
focal length and aperture as mentioned above necessitates a
switching action at a specific focal length in accordance with the
binary logic. However, in the case of the Fuzzy logic, the two
channels of functions work as if to obtain the weighted means of
the conditions and, as shown in FIGS. 51 and 52, the functions
correctly work without complementary branching conditions.
Generally, the frequency of use of photographing distance varies
with the focal length. FIG. 53 shows an example of the frequency
obtained with generally employed focal lengths. FIG. 54 shows an
example of the frequency obtained with telephoto focal lengths.
FIG. 55 is a flow chart showing an operation performed according to
the above-stated frequency by means of a microcomputer, etc. The
operation is as follows: At a step #101: Weight is attached to a
degree coinciding with the frequency of the use of photographing
distances according to the focal length. For example, in a case
where the frequency of use of the left distance measuring area at a
short focal length, the left measured distance value is heavily
weighted if the focal length currently in use is short.
The embodiment described above is arranged to measure distances
through the left, center and right distance measuring points of the
photographing picture plane; to judge the possibility of that the
measured distance values is a distance to an obstacle such as the
ground or the like on the basis of information on a difference
between measured distances, information on the posture of the
camera and information on measured light values obtained for the
distance measuring points; to determine the degree of weight to be
attached to the measured distance information by taking into
consideration the result of the judgment in computing lens driving
information. The arrangement thus enables the lens to be driven and
controlled in a manner apposite only to the object to be
photographed. Therefore, photographing can be accomplished to
obtain a sharply focused picture.
Further, since the above-stated actions are automatically
performed, a picture can be taken with the object in focus even
when framing is freely selected. In addition to that advantage, the
embodiment also permits adequate exposure control. In other words,
the embodiment gives an automatic focusing camera which is capable
of correctly focusing and adequately controlling an exposure
without requiring the attention of the photographer to the distance
measuring field.
Next, an embodiment of the invention wherein the Fuzzy theory is
furthered is described in detail below:
FIG. 57 shows the fundamental arrangement of the embodiment.
Measured distance values obtained from an upper-left distance
measuring system 501, a center distance measuring system 502 and a
lower-right distance measuring system 503 which are arranged for a
viewfinder field which will be described later are supplied to a
4-bit microprocessor 504. The microprocessor 504 is arranged as
follows: A first priority means 505 is arranged to give priority to
the measured distance value which indicates the nearest distance
among the values obtained by the distance measuring systems 501 to
503. The first priority means 505 produces the result of giving
priority or the degree of priority given. A second priority means
506 is arranged as follows: In a case where the measured distance
value of one of the distance measuring systems other than the
center distance measuring system 502, say, the lower-right distance
measuring system 503 (hereinafter referred to as the right measured
distance value) indicates the nearest distance, the means 506 gives
priority to the measured distance value of the center distance
measuring system 502 (hereinafter referred to as center measured
distance value) if the center measured distance value indicates a
medium distance while that of the upper-left distance measuring
system 501 (hereinafter referred to as left measured distance
value) with these values being in a near-medium-far relationship.
The second priority means 506 then produces the result of giving
priority or the degree of the priority. A priority limiting means
507 is arranged as follows: In a case where the center measured
distance value and another measured distance value or, for example,
the right measured distance value are close to each other and one
of them is the nearest distance, other measured distance value or,
for example, the left measured distance value is lightly
considered. The priority limiting means 507 then produces the
result of the light consideration or a reduced degree of priority.
A third priority means 508 is arranged as follows: In a case where
both the left and right measured distance values indicate very near
distance and the center measured distance value indicates a
relatively far distance, the third priority means 508 allows the
center measured value to have priority over the left and right
measured distance values. If the left and right measured distance
values indicate near distances while the center measured distance
value indicates a relatively far distance, the third priority means
508 allows the left and right measured distance values to have
priority over the center measured distance value and produces the
result of giving the priority or the degree of priority given.
Selection means 509 is arranged to select one of the measured
distance values having the highest priority or the highest degree
of priority among the measured distance values on the basis of the
outputs of the priority means 505, 506 and 508 and the priority
limiting means 507. A computing means 510 is arranged to compute
and obtain lens driving information from the measured distance
value selected by the selection means 509. The lens driving
information then causes a focus adjustment driving system 511 to
focus the lens on an appropriate distance point for
photographing.
A RAM/ROM 512 is arranged to record the program and constants of
the microprocessor 504 and to temporarily store the outputs or the
means 505 to 510.
FIG. 58 shows the distance measuring areas L, C and R of the
above-stated upper-left distance measuring system 501, the center
distance measuring system 502 and the lower-right distance
measuring system 503 in relation to a viewfinder field 513.
With the embodiment arranged in the above-stated manner, the
embodiment operates as follows: The first priority means 505
computes basic near distance priority. The second priority means
506 computes center measured distance value priority for removal of
a nearby obstacle. The priority limiting means 507 computes the
lightly consideration of the far distance of a distance measuring
area which has a great degree of possibility of deviating from the
object to be photographed in the event of a close-up shot. Further,
the third priority means 508 computes priority for removal of any
nearby obstacle and also priority for preventing the disappearance
of the center area. The results of these computing operations are
subjected to overall judgment to select one of them. This
arrangement serves to enhance the accuracy of elimination of nearby
obstacles.
Before entering into details of this embodiment, the Fuzzy rules of
FIG. 21 are again described below:
The fuzzy rules of FIG. 21 include rules "a" to "e". The rules "a"
to "c" are provided for computation with priority given to the
basic near distance. The rules "d" and "e" are provided for
computation with priority given to the center measured distance
value in a case where the measured distance values are obtained in
an oriented alignment in the order of a near distance, a medium
distance and a far distance with the center measured distance value
indicating a medium distance in the middle of the alignment.
Further, In the case of the rule "a", the left measured distance
value is weighted according to the degree to which this distance is
close to 1 m which is a near distance weighting datum point. Then,
the possibility LR that the left measured distance value which is
thus weighted correctly represents the object's distance is
computed by means of the function .alpha.. In the rules "b" and
"c", the possibilities CR and RR that the center and right measured
distance values correctly represent the object's distance are
likewise computed.
The rule "d": The measured distance values are weighted according
to the degrees to which a difference between the left and center
measured distance values is positive and a large value and a
difference between the right and center measured distance value is
negative and a large value (the degree of far-medium-near
interrelation of the left, the center and the right). Then, the
possibility CR that the weighted measured distance value of the
center distance measuring system 502 is the most correct distance
value is computed by using the function .beta.. The function .beta.
is arranged to make the possibility greater than the function
.alpha.. The rule "e": The treatment of the left and right measured
distance values in the rule "d" is conversed in the rule "e".
In typical examples of photographing framing shown in FIGS. 59(a)
to 59(e), the relation of the rules "a" to "e" to the framing is as
described below:
In the case of FIG. 59(a), a main object is located in the center
of the frame. The center measured distance value is the closest to
1 m which is the near distance weighting datum in this case. Hence,
the possibility CR computed by the rule "b" has the highest value.
Other possibilities LR and RR computed by the rules "a" and "c"
respectively have low values. The near-medium-far measured distance
value orientation does not take place. Therefore, the possibility
CR which is computed by the rules "d" and "e" respectively is at a
low value. The possibility CR becomes the weighted mean of the
values obtained by the rules "b", "d" and "e" and thus gives a
highest degree of possibility. Therefore, the center measured
distance value is selected.
FIG. 59(b) shows the main object on the right side (or on the left
side). If the object is located near, the right (or left) measured
distance value is the closest to 1 m which is the near distance
weighting datum. Therefore, the possibility RR (or LR) computed by
the rule "c" (or the rule "a") becomes the highest value.
Accordingly, the right (or left) measured distance value is
selected in this instance.
FIG. 59(c) shows nearby objects both on the right and left sides.
In this case, the possibilities LR and RR are at the highest
values. Therefore, either the left or right measured distance value
is selected.
FIGS. 59(d) and 59(e) show a main object in the center of the
frame. If the left, center and right measured distance values are
in the interrelation of far-medium-near or near-medium-far, the
rule "a" or "c" gives a high value to the possibility LR or RR.
However, the possibility CR is allowed to have the highest value by
the rule "d" or "e" (because the function .beta. is larger than the
function .alpha.. As a result, the center measured distance value
is selected.
While the rules "a" to "e" of FIG. 21 are as described above, Fuzzy
rules used for this embodiment are as shown in FIG. 60,
wherein:
Rule 1 is the same as the rule "b" of FIG. 21. As shown at Rule 1
in FIG. 61, the result of computation indicates that the center
measured distance value which shows the nearest distance has the
highest possibility of being a correct distance value. Rules 2 and
3: They are about the same as the rules "a" and "c" of FIG. 21 and,
as shown at Rules 2 and 3 in FIG. 61, the result of computation
shows large possibility. However, the former differ from the latter
in that a wide angle of view is added to the antecedent. In the
case of a wide angle of view, assembled objects spread wide. This
strongly suggests that the objects located in the upper-left and
the lower-right parts of the picture plane (or frame) are not
obstacles. Rules 4 and 5: The rules 4 and 5 are about the same as
the rules "d" and "e" of FIG. 21 and, as shown at Rules 4 and 5 in
FIG. 61, the former differs from the latter in that a narrow angle
of view is added to the antecedent. A narrow angle of view means a
close-up shot. Then, in the event of a near-medium-far
interrelation, any object located closer than the center measured
distance is very likely an obstacle.
Further, the near distance weighting datum point is set at 1 m for
the center measured distance value in the same manner as in the
case of FIG. 21. However, for the right measured distance value,
the near distance weighting datum is set at 2 m for the purpose of
a possible distance measurement error due to the presence of the
ground. In this case, therefore, the weight is reduced for a
distance less than 2 m. As for the left measured distance value,
the near distance weighting datum point is set at 1.6 m considering
a balanced relation to the right measured distance value. For a
left measured distance value less than 1.6 m, the weight is
reduced. When the camera is held in a normal posture, the
upper-left distance measuring point measures a distance to an
object located higher than an object being measured by the
lower-right distance measuring point. Therefore, the ground
measuring error possibility of the upper-left distance measuring
point is less than that of the lower-right distance measuring
point. In a case where the camera is held in a vertical posture,
however, the upper point becomes lower and its ground measuring
error possibility becomes higher than that of the center distance
measuring point. In view of this, the near distance weighting datum
is set at 1.6 m as an intermediate value between the data provided
for the center and lower-right distance measuring points.
In the case of this embodiment, rules 6 to 10 are newly added. The
rules 6 and 7 are arranged as follows: Measured distance values
indicating very near distances not always represent obstacles. In
the case of a close-up shot, for example, the distance measuring
area on one side L or R might be outside of the main object. In
this instance, the distance measuring areas in the center and on
the other side are covering the object located at a very near
distance. The measured distance value of the center and that of one
side become about equal to each other and indicate very near
distances while that of the other side indicates a relatively far
distance. The rules 6 and 7 are added for the purpose of lowering
the evaluation rate of the possibility that the measured value of
the far distance is correct under such conditions. Rule 6: Measured
distance values are weighted according to the degree to which the
left and center measured distance values are equal to each other;
the degrees to which the left and center measured distance values
are close to a very near distance weighting datum point 0.5 m; and
the degrees to which the distance indicated by the right measured
distance value is farther than the center measured distance value
and farther than the left measured distance value respectively.
Then, the possibility of judging that the right measured distance
value is the most correct measured distance value is computed to be
lower that other measured distance value by using an applicable
function. In the Rule 7: The relation between the left and the
right obtained in the rule 6 is conversely handled. By virtue of
the rules 6 and 7, the likely out of-place measured far distance
value is lightly handled.
FIG. 62 shows a similar case, wherein there are very near obstacles
on both sides. In such a case, the parallax of the view finder
tends to prevent the photographer from confirming the presence of
the obstacles. The rule 8 is added in view of this. As stated at
the Rule 8 in FIG. 61, the very near obstacles on both sides are
lightly treated while importance is attached to the center measured
distance value. Rule 8: Measured distance values are weighted
according to the degree to which the left and right measured
distance values are about equal to each other; the degrees to which
the left and right measured distance values are close to the very
near distance weighting datum 0.5 m respectively; and the degrees
to which the center measured distance value is relatively farther
than the left and right measured distance values. Among these
weighted distance values, the rate of possibility that the center
measured distance value is the most correct value is computed to be
the highest by the applicable function.
In the case of the rule 8, the very near obstacles located on both
sides are lightly treated. However, the addition of the rule 8
weakens the near distance priority rules 2 and 3. As a result, the
two persons which are located on both sides as shown in FIG. 59(c)
might be mistaken for obstacles. To solve this problem, rules 9 and
10 are also added. The rules 9 and 10 partly overlap the rules 2
and 3 but include provisions for attaching importance to the
measured distance values obtained from the left and right sides in
a case where they both indicate near distances which do not much
differ from each other while the center measured distance is
relatively farther than them. Rules 9 and 10: The measured distance
values are weighted according to the degree to which the left and
right measured distance values are about equal; the degrees to
which the left and right measured distance values are close to the
near distance weighting datum points 0.1 m and 1.6 m respectively;
and the degrees to which the center measured distance is relatively
farther than the left and right measured distance values
respectively. Then, the rate of possibility that the left or right
measured distance value is the most correct distance value is
computed to be high by an applicable function.
These rules 1 to 10 are subjected to a computing operation. This is
a Fuzzy computing operation involving 10 rules having 22 antecedent
membership functions and 3 consequent membership functions. One
rule has a maximum of 5 antecedent membership functions. Three or
four rules are required before obtaining three outputs. Therefore,
errors tend to enter in the inside computation of each rule and in
the computation between one rule and another.
In the case of this embodiment, the following contrivance is made
to permit use of a general-purpose low-cost microprocessor:
The consequent membership functions are modified to have the
probabilities uniformly determined in relation to input
probabilities. In addition to that, a weighted mean value of
probabilities which are weighted by input probabilities is arranged
to be obtained in the inter-rule computation. This means an
expansion of the maximum value of the membership functions of sum
computation by the Fuzzy theory into an algebraic sum. The weighted
mean remains the same as long as the consequent membership function
is exclusive. It differs in that the overlapping parts are
computed. Generally, Fuzzy computation is performed according to
rules as shown in FIGS. 63(a) and 63(b).
In the case of the rule of FIG. 63(a), the antecedent membership
function is computed for an input X10. The membership degree
hA1(X10) of the function is obtained. Then, either the gain of the
consequent membership function is changed by using the degree
hA1(X10) (a blackened part of the drawing) or, although not shown,
the membership function of the rule is obtained by setting the
upper limit of the membership function.
In the case of using two rules as shown in FIG. 63(b), X10 and X20
are included in two antecedent membership functions. Then, the
membership degrees of these functions become hA2(X10) and hB2(X20).
The least of the membership degrees hA2 and hB2 is obtained and
hB2(X20) is obtained as the result of AND obtained for the rule.
The gain of the consequent membership function is changed by means
of the membership degree hB2(X20) as shown in the drawing (a
blackened part). In another method, although it is not shown, the
upper limit of the membership function is set and is used as the
membership function of the rule. As for inter-rule computation, a
membership function having the maximum value of the membership
functions resulting from the rules is computed in a manner as shown
at a part (6) in FIG. 63(b). Then, the barycenter position Uo of
this membership function is obtained as the conclusion of the
operation.
While the Fuzzy computation generally practiced is as shown in
FIGS. 63(a) and 63(b), the embodiment of this invention performs
computing operations in the following manner: In carrying out
rules, the barycenter positions and heights are recorded and weight
attaching degrees are averaged. This method is deemed to correspond
to a method of carrying out barycenter computation including the
overlapped part shown in a blank triangle between two blackened
triangles at the part (6) in FIG. 63 (in cases where the base of
the consequent function has a fixed length). The computing
operation is, so to speak, performed with two variables to obtain
about the same result as the general Fuzzy computation having a
width from a point "0" to a point "z" of FIGS. 63(a) and 63(b)
without performing the computation of the figure (array) up to its
height "1.0" as shown in these drawings.
The membership functions to be used by this embodiment are as
described below:
These functions are prepared according to the Fuzzy rules of FIG.
60. FIG. 64 shows the antecedent membership functions of the rules
1 to 3. The axis of abscissa of FIG. 64 shows distances between an
infinity distance and 0.5 m with the infinity distance set a the
zero point. These distances are expressed in AF data obtained by
integrating pulses generated every time a distance ring is turned
round a given degree of angle. The upper axis of abscissa shows the
data in hexadecimal values and the lower axis of abscissa in
decimal values. The left axis of ordinate shows the degrees of
weight from 0 to 1. The right axis of ordinate shows the degrees of
weight in hexadecimal values for input to the microprocessor. In
respect to the "near" of the antecedent parts of the rules 1 to 3,
a membership function which has its peak at about 1 m thus
indicating the general photographic notion of "near" (not "very
near") is used for the center distance measuring point as shown in
FIG. 64. As for the left and right distance measuring points, the
measured near distance values are expressed in triangular forms
having peak values at 1.6 m and 2 m respectively because of the
possibility that a ceiling or a ground is unintentionally measured.
Distances farther than 1.6 m and 2 m are handled with priority
given to near distances. Distances nearer than 1.6 m and 2 m are
lightly handled.
As regards computation, the degrees of membership are computed
according to formulas (1), (2), (3) and (10) shown in FIG. 65. For
the "and" within each rule, the minimum value of the membership
degree is used.
FIG. 66 shows the consequent membership functions of the rules 1 to
10. In FIG. 66, the lower axis of abscissa shows the weight of the
antecedent part. The upper axis of abscissa shows the weight in
hexadecimal values for input to the microprocessor. The left axis
of ordinate shows the possibility of correctness of the measured
distance values in decimal values. The right axis of ordinate shows
the same possibility in hexadecimal values for input to the
microprocessor. The consequent parts of the rules 1 to 3 are
arranged as follows: For inter-rule computation with weighted mean
as mentioned in the foregoing, functions showing probability rates
50% (80 H) to 100% (FFH) for the membership degrees 0 to FFH are
used as shown in FIG. 66. The computation of this is performed
according to a formula (11) shown in FIG. 65.
The rules 4 and 5 give priority to the center measured distance
value in the case of the far-medium-near measured distance
condition as mentioned in the foregoing. Since such condition is
possible within a wide distance range, the judgment for far and
near distances is made relative to the center measured distance
value. In addition to that, the consequent parts of the rules 4 and
5 are arranged to be strong for the purpose of prevailing over the
rules 1 to 3. Therefore, as shown by a dotted line in FIG. 67 (the
axes of ordinate and abscissa are arranged in the same way as FIG.
64), the "nearer than" of the antecedent membership function gives
1.0 (FFH) if the distance becomes about one half (if apparently
near as judged from the depth of field).
Further, with respect to the part "medium", a membership function
which gives a maximum weight 1.0 (FFH) to a distance between 1.2 to
2.5 m at which pictures of persons are often taken in general as
shown in FIG. 68 (the axes of ordinate and abscissa are arranged in
the same way as in FIG. 64).
The part "angle of view is narrow" is a function which is
complementary to the part "angle of view is wide" of the rules 2
and 3. In the case of zooming of the lens, the angle of view is
changed in an analog manner. This part is provided because the
layout of picture composition changes with the angle of view. The
layout changes to a greater degree in the case of change-over of
photo-taking size between a full size and a half size. In the case
of this embodiment, therefore, membership degrees which are
determined according to the full-size or half-size photographing
are set. FIG. 69 shows an example of this setting at a formula (9)
which is provided for that purpose.
Further, with respect to the consequent membership functions of the
rules 4 and 5, functions are arranged to give, so to speak, the
square of the part "high" (a dotted line of FIG. 67) as indicated
by a full line in FIG. 67. The function is thus arranged to give a
higher value of possibility than the antecedent part.
FIG. 69 shows the program of this embodiment. In this program, a
shifting process using linear interpolation with easily computable
multiples in place of time consuming multiplication. As a result,
the shape of the function somewhat deviates from the ideal curve
thereof as indicated by a broken line in FIG. 68.
The rules 6 and 7 are provided for a case where distances to "two
points which are very near and are nearly equal to each other" and
that of a point deviating at an end part. For the part "nearly
equal", a membership function which gives zero when distances
differ as much as two times is used as shown in FIG. 67. For the
part "very near," a membership function which increases the weight
within 1.2 m as shown in FIG. 70 (axes of ordinate and abscissa are
arranged in the same way as in FIG. 64) is used. Used for the part
"relatively farther", is a membership function which gives 1.0
(FFH) for a distance differing to a great degree such as an
infinity distance or 1.5 m as shown in FIG. 67. For a program, the
embodiment employs proximity computation as shown in FIG. 71.
For the part "possibility is low", a function which lowers the
possibility accordingly as the antecedent membership degree
increases is used.
The membership functions are again described as follows: The
membership functions for the part "near" varies according to the
use of it for the center, right or left measured distance value,
because: As mentioned in the foregoing, the lower-right distance
measuring point has a high degree of possibility of mistaking an
obstacle for the object is high. Hence, the membership function is
lowered for the lower-right distance measuring point in the case of
a distance nearer than 2 m. The same sort of mistaking is possible
with the upper-left distance measuring point in the event of
vertical posture photographing when it is turned round 90 degrees
to the left. Therefore, for the left measuring point, the
membership function is lowered for an upper-left measured distance
nearer than 1.6 m. Further, in the case of a distance farther than
2 m, a function similar to that of the center measuring point is
provided for the left and right distance measuring points to
compare the membership degree with that of the center distance
measuring point on the same level. As for very near distances, a
function is formed in such a way as to have a membership degree
lower than the center distance measuring point. A membership
function for the part "relatively farther", is arranged to indicate
that the distances are differing more than two times and if the
lens is focused on one distance, the other would be out of
focus.
FIG. 72 is a flow chart showing a program provided for this
embodiment. At a step #1: Information on the measured distance
values is received from the distance measuring systems 501 to 503.
At a step #2: Each of the input values is limited according to a
distance range. Steps #3 to #8 are provided for computing the
possibility of that the measured distance value of the center
distance measuring point is the most correct distance value. At the
step #3: Initial setting is performed. At the step #4: A computing
operation is performed according to the rule 1 (FIG. 61). At the
step #5: A computing operation is performed according to the rule
4. At the step #6: A computing operation is performed according to
the rule 5. At the step #7: A computing operation is performed
according to the rule 8. At the step #8: The barycenter of the
weighted measured distance value of the center distance measuring
point is obtained. Steps from #9 through #13 are provided for
computing the possibility of that the measured distance values
obtained from the left distance measuring point is the most correct
distance value. At the step #9: Initial setting is performed. At
the step #10: A computing operation is performed for the rule 2. At
the step #11: A computing operation is performed for the rule 7. At
the step #12: A computing operation is performed for the rule 9. At
the step #13: The barycenter of the weighted measured distance
value of the left distance measuring point is obtained. Steps from
#14 through #18 are provided for computing the possibility of that
the measured distance value obtained from the right distance
measuring point is the most correct distance value. At the step
#14: Initial setting is performed. At the step #15: A computing
operation is performed for the rule 3. At the step #16: A computing
operation is performed for the rule 6. At the step #17: A computing
operation is performed for the rule 10. At the step #18: The
barycenter of the weighted distance value of the right distance
measuring point is obtained. At a step #19: One of the measured
values having the largest barycenter is selected. At a step #20:
The selected measured distance value is output as the most correct
measured distance value.
FIGS. 73 to 80 show program examples for actually executing the
program shown in FIG. 72. These programs conform to the ISO/JIS
FORTRAN. According to these programs, three distance values are
obtained from a file address 5 and the results of selection, etc.
are written in a file address 6. Further, a mark " is used for
inline comments.
FIG. 73 shows steps #1 and #2. At the step #1: The measured
distance values of the center, right and left distance measuring
points are received. At the step #2: The input values are
limited.
FIG. 74 shows a part for obtaining the probability of the center
measured distance value. A membership function MF1C (for center
measured distance value) is used for the rule 1. With its
membership degree obtained by a function of "high possibility", the
integrated value of weighting SPPW and that of weight SPW are
obtained. (Step #4)
In the computing operation for the rule 4, the part "L (left
measured distance) is nearer than C (center measured distance)" is
computed with a membership function MF4. The part "C is medium" is
computed with a membership function MF3. The part "C is nearer than
R (right measured distance)" is computed with the membership
function MF4. The part "angle of view if narrow" is computed with a
membership function MF7. Then, using the MIN0 of each of the
incorporated functions, the minimum value of the membership degree
is obtained. According to the result of this, the integrated value
of weighting SPPW and the integrated value of weight SPW are
obtained with the function of "possibility is very high" of the
consequent membership function. (Step #5)
Following the above, a computing operation is performed for the
rule 5. The part "R is nearer than C" is computed with the
membership function MF4; the part "C is medium" with the membership
degree which has been computed and held at "P22"; the part "C is
nearer than L" with the membership function MF4; and the part
"angle of view is narrow" with the membership function MF7,
respectively. Then, according to a minimum membership degree thus
obtained, the integrating computation is performed on the
consequent part with a consequent part function for "probability is
very high". (Step #6)
A computing operation for the rule 8 is likewise performed. The
part "L and R are nearly equal" is computed with a membership
function MF6. The part "L is very near" is computed with a
membership function MF2. The part "R is very near" is computed with
the membership function MF2. The part "C is relatively farther than
L" is computed with a membership function MF5. The part "C is
relatively farther than R" is computed with the membership function
MF5. Then, using each membership degree at its minimum value, the
membership degree is computed with a consequent membership function
for "very high". (Step #7)
Then, the overall probability (overall barycenter position) is
obtained from the probabilities (barycenter positions) of the
consequent membership degrees with the overall probability weighted
by membership degree (weight) of each probability in the following
manner: Overall probability=.SIGMA.((membership degree of i-th
rule) * (probability of i-th rule)) / .SIGMA. (membership degree of
i-th rule). Through this process, the overall probability can be
numerically obtained "without computing the array of the functional
forms of the consequent membership function". (Step #8)
FIG. 75 shows a program part for obtaining the probability of the
left measured distance value. The consequent membership functions
are computed for the rules 2, 7 and 9; and the probability of the
left measured distance value is obtained by obtaining weighted mean
values of the results of computation. (Steps #9 to #13)
FIG. 76 shows a program part for obtaining likewise the probability
of the right measured distance value (steps #14 to #18) and another
program part for selecting and producing one of three probability
rates (steps #19 and #20). The probability of the right measured
distance value is obtained by computing the consequent membership
for each of the rules 3, 6 and 10 (10 is the same as 9 in respect
to the formula).
The selection of one of three probability rates is made by
producing a distance value corresponding to the largest of the
three. In the event of equal rates, the center measured distance
value is produced.
FIGS. 77 to 80 show function programs for the membership functions
to be used for the program described in the foregoing. For
obtaining the membership functions mentioned after the description
of FIG. 64 are programmed according to the formulas shown in FIGS.
65, 69 and 71.
For example, the function for "near" of the membership function
MF1C relative to the center distance measuring point is programmed
to be zero for distances not exceeding 33 (far side). Distances
between 33 and 118 have an increasing function which increases from
zero to 255. Distances between 118 and 191 have a decreasing
function which decreases from 255 to zero (greater, than zero). For
distances above 191 (near side), zero is given back. (FIG. 65,
(1))
The membership functions MF1L and MF1R for "near" for the left and
right distance measuring points are arranged to decrease for
distances exceeding (or nearer than) 76 and 88. (FIG. 65, (2) and
(3))
FIG. 78 shows a function program arranged to show the function MF2
for "very near" by a function which becomes large at a near
distance between distances from 107 to 192 (FIG. 71, (4)); and to
show the function MF3 for "medium" by a trapezoidal membership
function having 38 to 192 as the bottom and 67 to 106 as the upper
side thereof. (FIG. 69, (5)) Further, the function MF4 for "x is
nearer than y" is expressed by a membership function which
increases the distance difference of the function MF4 from 0 to 29.
(FIG. 69, (6))
FIG. 79 shows a function program which expresses a function MF5 for
the part "x is relatively farther than y" (a membership function
which decreases at a distance difference from -56 to zero,--FIG.
71, (7)); a function MF6 for the part "x and y are nearly equal" (a
membership function which increases the absolute value of
difference at below 29, --- FIG. 71, (8)); a function MF7 for the
part "angle of view is narrow" (FIG. 69, (9)); and a function for
the part "angle of view is wide" (FIG. 65, (10)).
FIG. 80 shows a program for the consequent membership function and
the integrating part of the consequent part. A function HIGH
showing the part "possibility is high" is provided for computing a
weighted mean value weighted by probability rates from 128 to 255
and membership degrees according to membership degrees from zero to
255 of the antecedent part. For this purpose, integrating
operations are performed on the product of the two and the
membership degree through common variables SPPW and SPW. (FIG. 65,
(11))
The program is thus arranged as follows: The probability rate of
128 (meaning 50%) is lightly weighted on the average if the
membership degree is low. The probability rate of 255 (meaning
100%) is heavily weighted on the average if the membership degree
is high. A function LOW for showing the part "possibility is low"
is arranged to average weight the probability rates of 128 to zero
according to the zero to 255 of the antecedent membership function.
(FIG. 71, (12))
A function EXHIGH for the part "possibility is very high" is
arranged to produce and average weight the probability rates of 132
to 255 (probability of that the same membership degree is higher
than HIGH) according to the membership degrees of zero to 255.
(FIG. 69, (13))
Briefly stated, the actions described above perform, so to speak,
color sorting as to which of the three measured distances is to be
selected by using the Fuzzy rules within a three-dimensional space
consisting of the three distances.
However, it is an advantageous feature of this embodiment that a
complex color sorting process which is more effective than a color
sorting process based on a simple near-priority rule can be
accomplished through adjustment made by intuitive Fuzzy rules.
In actuality, scenes to be photographed consists of a combination
of varied distances. Selection of an optimum distance from among a
variety of distances can be accomplished by methods of varied
kinds. In the light of this, the use of the intuitive Fuzzy rules,
adjustment according to the rules and the arrangement to have them
simply programmed within a microprocessor are believed to give a
good machine.
FIGS. 81, 82(a), 82(b), 83(a), 83(b), 84(a), 84(b), 85(a) and 85(b)
show an embodiment of this invention wherein the Fuzzy theory is
programmed for a practical machine product. In this case, the
FORTRAN program of FIGS. 73 to 80 described in the foregoing is
programmed on a 4-bit microprocessor, Model No. 47C800, which is a
product of Toshiba.
Because of its character as an assembler, the center measured
distance value is located at an address AFCNTL. The membership
degree is obtained at an address 0.1 of a RAM by subroutine calling
each membership function. Then, according to the membership degrees
stored at addresses 20 and 21, the consequent membership is
computed. Each membership function MEMB** internally works as a
function equivalent to MEMF**.
At the start of the program, a RAM area is first cleared by means
of RAMCAF and the rule 1 is computed. An address indicative of
information about the distance of the center is placed in an HL
register. The membership degree of the membership function MEMBlC
is obtained from it. Its probability is computed by a PHIGH
(PROBBH). Next, the rule 4 is computed by designating the addresses
of the measured distance values of the center and the left. By
this, the membership degree of that "the left is nearer than the
center" is obtained with the membership function MEMBR4. Next, the
membership degree of the part "the center is medium" is obtained
with the membership function MEMBR3. Then the part "&" is
computed with a minimum function of FIG. 82.
Next, the membership degree of the part "the center is nearer than
the right" is obtained with the membership function MEMBR4. Then,
"&" is computed again with the minimum function. The part
"angle of view is narrow" is computed with the membership function
MEMBR7. Then "&" is computed. Probability is computed with
PHIGHX (=PROBBX).
Following this, a computing operation is performed for the rule 5.
The degree of that "the right is nearer than the center" is
computed with the membership function MEMBR4 which has the
addresses of the center and right measured distance values set
there. The degree of "the center measured distance value is medium"
and "&" stored at the addresses 22 and 23 of the RAM are
computed. Next, the measured distance value addresses of the left
and the center are set. The degree of "the center is nearer than
the left" is computed with the membership function MEMBR4. The
result of this and the degree of "angle of view is narrow" are put
together and the consequent part is integrated by a PHIGHX
(=PROBBX).
Next, a computing operation is performed for the rule 8. The
addresses of the right and left measured distance values are set.
The degree of "right and left measured distance values are nearly
equal" is obtained with the membership function MEMBR6 (=MEMF6).
With the address of the left measured distance value set, the
degree of "left measured distance value is very near" is obtained
with the membership function MEMBR2 (=MEMF2). With the address of
the right measured distance value set, the degree of "right
measured distance value is very near" is obtained with the
membership function MEMBR2. The addresses of the center and left
measured distance values are set and the degree of "the center is
relatively farther than the left" is obtained with the membership
function MEMBR5. Next, the center and right measured distance
values are set as shown in FIG. 84. The degree of "the center is
relatively farther than the right" is obtained with the membership
function MEMBR5. Their "&" is obtained and the integrated value
of the consequent part is obtained with the PHIGHX. The weighted
mean of the consequent part is obtained by DV20S and is set as the
probability of the center measured distance value.
Next, the probability of the left (measured distance value) is
obtained in the following manner: A computing operation is first
performed for the rule 2. The address of the left measured distance
value is obtained. The function MEMBR1L (=MEMF1L) is called to
obtain the membership degree of "the left measured distance value
is near for the left". Following this, the membership degree of
"the angle of view is wide" is obtained with the function MEMBR8
(=MEMF8). Then, the consequent part is integrated with PHIGH
(=PROBBH).
For the rule 7: the addresses of the center and right measured
distance values are set. The degree of "the center and right
measured distance values are near" is obtained by calling the
function MEMBR6. The degree of "the right is very near" and "&"
are computed. The address of the center measured distance value is
set. The function MEMBR2 is called to obtain the degree of "the
center is very near" together with "&". The addresses of the
left and right measured distance values are set and the function
MEMBR5 is called to obtain the degree of "the left is relatively
farther than the right". Next, the address of the left measured
distance value is set and the function MEMBR5 is called to compute
the degree of "the left is relatively farther than the center".
After that, according to the results of these computing actions,
PLOW (=PROBBL) is called to compute the degree to which the
probability of the left measured distance value is to be
lowered.
Referring to FIG. 84, a computing operation is performed for the
rule 9 in the following manner: The degrees of "the left and the
right are nearly equal" and "the left is near" which have been
computed are called. The address of the right measured distance
value is set. The function MEMBRlR (=MEMF1R) is called. With these
actions performed, the degree of "the right measured distance value
is near" is obtained. Then, the degrees of "the center is
relatively farther than the left" and "the center is relatively
farther than the right" are obtained. From these degrees, the
consequent membership degree is obtained by means of PHIGHX. After
that, the probability of the left measured distance value is
obtained with DV20S from the weighted mean thereof.
Next the probability of the right measured distance value is
obtained in the following manner:
For the rule 3, the degree of "the right is near" computed in the
above-stated manner and the degree of "the angle of view is wide"
obtained by the membership function MEMBR8 are "&"-computed.
Then, the consequent part is computed with PHIGH. For the rule 6,
the addresses of the center and left measured distance values are
set. The degree of "the center and left measured distance values
are close to each other" is obtained by calling the function
MEMBR6. Then, the degree of "the right is relatively farther than
the center" is obtained from the above-stated degrees of "the left
measured distance value is very near" and "the center measured
distance value is very near" by setting the addresses of the right
and left measured distance values; by obtaining the degree of "the
right is relatively farther than the left" obtained by calling the
function MEMBR5; by setting the addresses of the right and center
measured distance values as shown also in FIG. 85; and by calling
the function MEMBR5. Then, the degree to which the probability of
the right measured distance value is to be lowered is computed with
PLOW.
The probability of the rule 10 is integrated by calling PHIGHX
according to the membership degree of the above-stated rule 9.
Then, the barycenter probability of the left measured distance
value is computed by calling DV20S.
The probability rates of three measured distance values are
computed in the above-stated manner. After that, the probability
rates of the center and right measured distance values are compared
by DTCMPR. If the probability of the center is larger than that of
the right or equal to the latter, the probability rates of the left
and center measured distance values are compared with each other.
If the probability of the center is larger than or equal to that of
the left, the center measured distance value is decided to be the
final measured distance value.
If the probability of the center is found then to be less than that
of the left, the left measured distance value is decided to be the
final value. If the probability of the center is found to be
smaller than that of the right, the probability rates of the left
and the right are compared. If the probability of the left is found
to be larger than or equal to that of the right, the left measured
distance value is decided to the final value. If the probability of
the left is less than that of the right, the right measured
distance value is decided to be the final value.
As described in the foregoing, the action to obtain the probability
of each of a plurality of measured distance values as to
representing a distance to a main object to be photographed can be
programmed on the basis of the Fuzzy theory by simply converting
Fuzzy rules. The program can be changed by virtue of the sensory
language to permit easy adjustment of the apparatus. The program
thus can be changed to enable a 4-bit microprocessor not only to
discriminate obstacles but also to perform such elaborate or fine
control and adjustment as to select the measured distance value of
one of the center, left and right distance measuring points with
due consideration of those of other points.
In short, the selection of one of a plurality of measured distance
values can be accomplished by a microprocessor in accordance with
complex rules. A camera embodying this invention permits the
photographer to take a sharply focused picture without paying
attention to a distance measurement mark. Besides, the program
which is prepared by easy development of readily apprehensible
Fuzzy rules permits easy adjustment. The barycenter computation
utilizing the Fuzzy theory enables the program to be arranged in a
compact state.
According to the foregoing description, the embodiment is arranged
to have three distance measuring areas or points including the
center, upper-left and lower-right distance measuring points.
However, the invention is not limited to this. The distance
measuring points may be either or vertically aligned and the number
of them bay be increased to four or more.
This invention is applicable not only to a lens shutter type camera
which directly measures the object's distance but also applicable
to a single-lens reflex camera arranged to proximately convert a
lens position into a distance value. The invention is applicable
also to other optical apparatuses and optical systems.
* * * * *