U.S. patent application number 11/527289 was filed with the patent office on 2007-04-05 for imaging device, imaging method and program.
This patent application is currently assigned to CASIO COMPUTER CO., LTD.. Invention is credited to Kazunori Yanagi.
Application Number | 20070077053 11/527289 |
Document ID | / |
Family ID | 37902058 |
Filed Date | 2007-04-05 |
United States Patent
Application |
20070077053 |
Kind Code |
A1 |
Yanagi; Kazunori |
April 5, 2007 |
Imaging device, imaging method and program
Abstract
An imaging device equipped with an imaging system including an
imaging lens optical system which images an object, a flash
emitting unit which synchronizes imaging in the imaging system to
emit a flash having not less than a prescribed luminance in a sate
not less than a prescribed charged state by power to be charged,
and a control unit which determines whether an emission not less
than the luminance can be performed or not from the charged state
of the emitting unit and a charges state in the case of the
possibility of the emission, and performs imaging by use of the
emitting unit by increasing imaging sensitivity step by step in the
imaging system in response to the charging stage when it determines
that the emission can be performed.
Inventors: |
Yanagi; Kazunori;
(Akishima-shi, JP) |
Correspondence
Address: |
FRISHAUF, HOLTZ, GOODMAN & CHICK, PC
220 Fifth Avenue
16TH Floor
NEW YORK
NY
10001-7708
US
|
Assignee: |
CASIO COMPUTER CO., LTD.
Tokyo
JP
|
Family ID: |
37902058 |
Appl. No.: |
11/527289 |
Filed: |
September 26, 2006 |
Current U.S.
Class: |
396/166 ;
348/E5.036; 348/E5.038; 396/206 |
Current CPC
Class: |
H04N 5/2354 20130101;
G03B 2215/0571 20130101; G03B 15/05 20130101; H04N 5/2352 20130101;
G03B 2215/05 20130101 |
Class at
Publication: |
396/166 ;
396/206 |
International
Class: |
G03B 7/26 20060101
G03B007/26 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 30, 2005 |
JP |
2005-285739 |
Claims
1. Imaging device comprising: imaging means for imaging an object;
an auxiliary light source which synchronizes with imaging by the
imaging device to emit a flash having not less than a prescribed
luminance in a sate not less than a prescribed charged state by
power to be charged; determining means for determining a charging
amount from a charged state of the auxiliary light source; and
imaging control means for performing imaging by using the auxiliary
light source with imaging sensitivity of the imaging means
increased in response to the charging amount in imaging by the
imaging means.
2. The imaging means according to claim 1, wherein the imaging
control means performs imaging by use of the auxiliary light source
by changing a shutter speed in addition to increasing the imaging
sensitivity of the imaging means in response to the determination
from the determining means.
3. The imaging device according to claim 1, wherein the determining
means includes means for determining whether or not a light
emission with not less than the prescribed luminance can be
performed form the charged state of the auxiliary light source; the
imaging means corresponds to imaging in a camera-shake correcting
mode of images due to a hand movement; and the imaging control
means sets the imaging means to the camera-shake correcting mode of
the images due to the hand movement and performs imaging by
changing a shutter speed when the determining means determines that
the light emission cannot be performed.
4. The imaging device according to claim 1, wherein the imaging
control means performs imaging by use of the auxiliary light source
by increasing the imaging sensitivity of the imaging means in
response to the determination from the determining means and an
object distance.
5. The imaging device according to claim 1, wherein the imaging
control means uses a look-up table in which an imaging sensitivity
increment of the imaging means in response to a charged stage of
the auxiliary light source is stored in advance.
6. The imaging device according to claim 1, wherein the imaging
control means increases imaging sensitivity by a pixel addition
method for adding information of adjacent pixels.
7. The imaging device according to claim 1, wherein the imaging
control means obtains image data with increased sensitivity by
performing pixel additions to add a plurality of items of the image
data obtained by the imaging means through a plurality of times of
exposures continuous in terms of time in identical pixels.
8. An imaging method of an imaging device equipped with an imaging
unit which images an object, and an auxiliary light source which
synchronizes with imaging by the imaging unit to emit a flash
having not less than prescribed luminance in a sate not less than a
prescribed charged state by power to be charged, the imaging method
comprising: a determining step of determining a charging amount
from a charged state of the auxiliary light source; and an imaging
control step of increasing imaging sensitivity of the imaging unit
in response to the charging amount to perform imaging by using the
auxiliary light source in imaging by the imaging unit.
9. A program to be executed by a computer built in an imaging
device equipped with an imaging unit which images an object, and an
auxiliary light source which synchronizes with imaging by the
imaging unit to emit a flash having not less than prescribed
luminance in a sate not less than a prescribed charged state by
power to be charged, the program comprising: a determining step of
determining a charging amount from a charged state of the auxiliary
light source; and an imaging control step of increasing imaging
sensitivity of the imaging unit in response to the charging amount
to perform imaging by using the auxiliary light source in imaging
by the imaging unit.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of
priority from prior Japanese Patent Application No. 2005-285739,
filed Sep. 30, 2005, the entire contents of which are incorporated
herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an imaging device, an
imaging method and a program particularly appropriate to a digital
camera to carry out flash imaging.
[0004] 2. Description of the Related Art
[0005] In general, not exclusively limited to a digital still
camera or a silver film camera, but it is usual to control an
imaging operation for still image imaging with a flash that is an
auxiliary light source emitted. Namely, when the flash is fully
emitted one time for imaging, the imaging operation is controlled
so as to disable the next flash imaging until a charged state of a
large-capacity capacitor to emit the flash reaches an emission
allowable amount after the preceding flash imaging.
[0006] Therefore, specifically, in a state that a battery for a
power source has been consumed, it takes time until the next flash
imaging becomes possible after carrying out the flash imaging once,
and photo opportunities are probably missed frequently.
[0007] Leaving that situation, this patent applicant proposes the
following technique. Aiming at imaging an object in an appropriate
luminance while reducing an affect on a battery life as much as
possible, if a shutter speed to be set is slower than 1/60 second,
the technique corresponds to the luminance of the object without
emitting the flash with photographic sensitivity increasing. On the
contrary, if the shutter speed is slower than 1/60 second although
the ISO sensitivity has been maximized, the technique determines to
carry out a flash emission and also determines the sensitivity. If
the flash emission is determined as a necessary imaging condition
in the forgoing processing, the technique lowers the sensitivity to
terminate processing according to processing flow at the time of
half-depression of a shutter button when the reach distance of the
flash becomes not excessive to an object distance then determines
the sensitivity (for instance, patent document 1: Jpn. Pat. Appln.
KOKAI Publication No. 2005-204120).
PROBLEM TO BE SOLVED BY PRESENT INVENTION
[0008] The technique has been described in the aforementioned
patent document 1 suppresses the consumption of the battery by
suppressing emission driving of a flash in the case in which the
technique can correspond to a luminance intensity of the object
with sensitivity up to a settable maximum sensitivity. However, if
the battery has been consumed and if imaging which needs the flash
emission is performed, the technique still dose not solve a defect
such that there is every possibility of taking a time to charge the
flash and missing a photo opportunity.
BRIEF SUMMARY OF THE INVENTION
[0009] An object of the present invention is to provide an imaging
device, an imaging method and a program capable of performing
imaging without missing a photo opportunity.
[0010] An imaging device according to a preferred aspect of the
present invention includes imaging means for imaging an object, an
auxiliary light source which synchronizes with imaging by the
imaging device to emit a flash having not less than prescribed
luminance in a sate not less than a prescribed charged state by
power to be charged, determining means for determining a charging
amount from a charged state of the auxiliary light source, and
image control means for performing imaging by using the auxiliary
light source with imaging sensitivity of the imaging means
increased in response to the charging amount in imaging by the
imaging means.
[0011] An imaging method according to another preferred aspect of
the present invention of an imaging device equipped with an imaging
unit which images an object, and an auxiliary light source which
synchronizes with imaging by the imaging unit to emit a flash
having not less than prescribed luminance in a sate not less than a
prescribed charged state by power to be charged, the imaging method
includes a determining step of determining a charging amount from
the charged state of the auxiliary light source, and an imaging
control step of increasing imaging sensitivity of the imaging unit
in response to the charging amount to perform imaging by using the
auxiliary light source in imaging by the imaging unit.
[0012] A program according to another preferred aspect of the
present invention to be executed on a computer built in an imaging
device equipped with an imaging unit which images an object, and an
auxiliary light source which synchronizes with imaging by the
imaging unit to emit a flash having not less than prescribed
luminance and at not less than a prescribed charged state by power
to be charged, the program includes a determining step of
determining a charging amount from the charged state of the
auxiliary light source, and an imaging control step of increasing
imaging sensitivity of the imaging unit in response to the charging
amount to perform imaging by using the auxiliary light source in
imaging by the imaging unit.
[0013] Thereby, it becomes possible to perform the imaging without
missing the photo opportunity.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0014] FIG. 1 is an exemplary block diagram illustrating a
functional configuration of an electronic circuit of a digital
camera regarding a first embodiment of the present invention;
[0015] FIG. 2 is an exemplary flowchart illustrating a processing
content in imaging mode regarding the first embodiment;
[0016] FIG. 3 is an exemplary view exemplifying a charging property
of a large-capacity capacitor for a flash regarding the first
embodiment;
[0017] FIG. 4 is an exemplary view exemplifying a content of a
look-up table defining a presence or absence of a flash emission
and ISO sensitivity corresponding to an amount of stored electric
power regarding the first embodiment;
[0018] FIG. 5 is an exemplary flowchart illustrating a processing
content in an imaging mode of a digital camera regarding a second
embodiment of the present embodiment,
[0019] FIG. 6 is an exemplary view exemplifying a content of a
look-up table defining a presence or absence of a flash emission,
ISO sensitivity and a shutter speed (S value) corresponding to an
amount of stored electric power regarding the second
embodiment;
[0020] FIG. 7 is an exemplary flowchart illustrating a processing
content in an imaging mode of a digital camera regarding a third
embodiment of the present invention; and
[0021] FIG. 8 is an exemplary view exemplifying a content of a
look-up table defining ISO sensitivity corresponding to an amount
of stored electric power and an object distance regarding the third
embodiment.
DETAILED DESCRIPTION OF THE INVENTION
First Embodiment
[0022] Hereinafter, first embodiment in the case in which the
present invention is applied to a digital camera will be described
with reference to the drawings.
[0023] FIG. 1 shows a conceptual configuration of an electronic
circuit of a digital camera 10.
[0024] In FIG. 1, in a monitoring state in an imaging mode,
positions of a part of lenses in an imaging lens optical system 12,
more specifically, positions of a zoom lens and a focus lens are
arbitrarily moved by means of driving of a motor (M) 11. A
charge-coupled device (CCD) 13 that is a solid imaging device is
disposed at an imaging position at the rear of the imaging axis of
the optical system 12 thorough a not shown mechanical shutter.
[0025] The CCD 13 is scanning-driven by a timing generator (TG) 14
and a CCD driver 15 to output a photo-electrically converted output
by one screen corresponding to an optical image formed for each
fixed period.
[0026] An auto gain control/sample hold (AGC/SH) circuit 16
sample-holds the photo-electrically converted output for each three
fundamental color of RGB in a state of signals of analog values
after gain-adjusting in response to the ISO sensitivity set at that
time point to transmit it to an ANALOG-TO-DIGITAL converter 17.
[0027] The ANALOG-TO-DIGITAL converter 17 converts image data of a
hole into digital data in accordance with an image size and an
image quality set at that time point to output it to a color
processing unit 18.
[0028] The color processing unit 18 performs a color process
processing including a pixel interpolation processing and a .gamma.
interpolation processing to digital pixel data and generates a
brightness signal Y and color difference signals Cb and Cr of
digital values to output them to a direct memory access (DMA)
controller 19.
[0029] The DMA controller 19 writes in the brightness signal Y and
the color difference signals Cb and Cr output from the color
processing unit 18 into a buffer inside the DMA controller 19 once
by using a composite synchronous signal, a memory writing enable
signal and a clock signal similarly output from the process circuit
18 to conduct DMA transfer to a DRAM 21 used as a buffer memory via
a DRAM interface 20.
[0030] A control unit 22 is composed of a CPU, a nonvolatile memory
such as a flash memory with an operation program, including a flash
emission and enhancement of sensitivity in the below-mentioned time
of imaging, fixedly stored therein and a RAM used as a work memory.
The control unit 22 controls a control operation of the whole of
the digital camera 10.
[0031] The operation program executed by the control unit 22
includes a determining means 221 and an image control means
222.
[0032] After completing the DMA transfer of the brightness signal Y
and the color difference signals Cb and Cr to the DRAM 21, the
control unit 22 reads out them from the DRM 21 via the DRAM
interface 20 to writes in them in a VRAM 24 through a VRAM
controller 23.
[0033] A digital video encoder 25 periodically reads out the
brightness signal Y and the color difference signals Cb and Cr from
the VRAM 24 through the VRAM controller 23 and generates a video
signal on the basis of such data to output it to a display unit
26.
[0034] The display unit 26 consists of, for instance, a color
liquid crystal panel with a backlight and its driving circuit
disposed on the housing rear face of the digital camera 10. In the
imaging mode, it functions as an electronic finder, and
reproduction-displays selected image, etc., at the time of a
reproduction mode while monitor-displaying in real time an image
based on image information already taken from the video encoder 25
at that time point with a display based on the video signal from
the video encoder 25 displaying.
[0035] Like this manner, in a display state of a so-called through
image in which an image at that time point is displayed on the
display unit 26 as a monitor image in real time, operating a
shutter button composing a part of a key input unit 27 at the
timing that still image photographing is desired to be done
generates a trigger signal.
[0036] The control unit 22 stops the DMA transfer of the brightness
signal Y and the color difference signals Cb and Cr by one screen
taken from the CCD 13 at that time point in response to the trigger
signal to the DRAM 21. The control unit 22 newly drives the
mechanical shutter (not shown) and the CCD 13 at a shutter speed in
accordance with appropriate exposure conditions to obtain a
start-up signal and a color difference signal by one screen. The
control unit 22 transfers them to the DRAM 21, then after this,
stops the path to transit to a storage state.
[0037] In the storage state, the control unit 22 reads out the
brightness signal Y and the color difference signal Cb and Cr by
one frame written in the DRAM 21 in units referred to as basic
blocks of height 8-pixel by width 8-pixel for each component of Y,
Cb and Cr via the DRAM interface 20 to write in them in a joint
photograph coding experts group (JPEG) circuit 28. The JPEG circuit
28 encodes them by means of a data compression processing such as
an adaptive discrete cosine transform (ADCT) and a Huffman coding
that is an entropy coding method.
[0038] The control unit 22 then reads out the obtained coded data
as a data file by one image from the JPAG circuit 28 and writes in
it in a built-in memory 29 that is a storage medium of the digital
camera 10 or in a memory card 30 detachably mounted on the digital
camera 10.
[0039] With the completion of writing of compression processing of
the brightness signal Y and the color difference signals Cb and Cr
by one frame and of writing of the whole of the compressed data in
the built-in memory 29 or the memory card 30, the control unit 22
starts up again the path from the CCD 13 to the DRAM 21.
[0040] Here, it is presumed that the memory car 30 takes a priority
over the built-in memory 29 and the memory card 30, and writes and
reads out a variety of items of data from image data of a still
image down. That is, in a state in which the memory card 30 has
been removed from the digital camera 10 and is not present, the
digital camera 10 writes in and/or reads out the data to and from
the built-in memory 29, and otherwise, in the state in which the
memory card 30 is mounted thereon, it writes in and/or reads out
the data to and from the memory card 30.
[0041] The key input unit 27, a sound processing unit 31 and a
flash driving unit 32 are connected to the connecting unit 22.
[0042] The key input unit 27 is composed of a power source key,
zoom key, imaging mode key, reproduction mode key, cursor key, set
key, menu key, macro key, flash key, etc., in addition to the
aforementioned shutter button, and signals with those key
operations are transmitted to a direct control unit 22.
[0043] The sound processing unit 31 has a sound source circuit such
as a PCM sound source to digitize a sound signal input from a
microphone unit (MIC) 33 disposed on the front face of the housing
body of the digital camera 10 in recording the sound. The
processing unit 31 generates a sound data file with data
compressing in accordance with a predetermined data file form, for
instance, the moving picture coding experts group-1 audio layer 3
(MP3) standards, and outputs it to the built-in memory 29 or memory
card 30. On the other hand, in reproducing the voice, the digital
camera 10 decompresses the sound data file read out from the
built-in memory 29 or the memory card 30 to analog-convert it and
drives a loudspeaker unit (SP) 34 disposed on the rear face side of
the digital camera 10, in the same manner as the display unit 26 is
disposed, to amplify and output it.
[0044] The flash driving unit 32 charges the not shown
large-capacity capacitor for the flash in imaging the still image,
then, flash-drives a flash emitting unit 35 composed of a xenon
discharge lamp, etc., on the basis of the control from the control
unit 22.
[0045] However, in the case in which imaging of not a still image
but a motion image is selected in the imaging mode, at the time
when the shutter button is operated for the first time, the control
unit 22 starts to continuously execute a series of operations for
obtaining the still image data to compress it by means of the JPEG
circuit 28 and storing it in the built-in memory 29 or the memory
card 30 at an appropriate frame rate, for example, 30 frame/sec.
And then at the time when the shutter button is operated for the
second time, or after the elapse of a prescribed limited time, for
instance, 30 seconds, the digital camera 10 integrates the series
of the still image data files to reset them as a data file of a
motion JPEG (AVI file).
[0046] In the reproduction mode, the control unit 22 selectively
reads out the image data stored in the built-in memory 29 or the
memory card 30, the JPEG circuit 28 expands the image data
compressed through the absolutely opposed procedure to the
procedure of the data compression in the imaging mode to store the
expanded image data on the DRAM 21 via the DRAM interface 20. The
control unit 22 then stores the content stored in the DRAM 21 onto
the VRAM 24 via the VRAM controller 23. The encoder 25 reads out
the image data periodically from the VRAM 24 to generate the video
signal then reproduces it on the display unit 26.
[0047] If the selected image data is not the still image but the
motion image, the control unit 22 continuously executes the
reproduction of each still image data consisting of the selected
motion image file in prescribed frames in terms of time. At the
time when the reproduction of the last still image data is
completed, the control unit 22 performs a reproduction-display by
using only the still image data positioned at a top until an
instruction for the next reproduction will be issued.
[0048] Operations of the foregoing embodiment will be described
below.
[0049] Like generic other cameras, it is assumed that, in the
digital camera 10, the shutter button has an operation stroke of
two stages to execute an imaging operation based on operation logic
as follows. Namely, as a first stage, the digital camera 10
executes an operation up to a half extent of a full stroke and a
automatic focusing (AF) processing and an automatic exposure (AE)
processing in an operation state generally referred to as the
half-depression of the shutter button to lock each processing
value. And after this, as a second stage, it executes regular
imaging depending on the AF value and AE value in an operation
state of the full stroke, generally referred to as full-depression
of the shutter button.
[0050] FIG. 2 shows a content of a processing executed in the case
in which the digital camera 10 images the still image in the
imaging mode, and the processing is basically executed on the basis
of the control by the determining means 221 and photographing
control means 222 of the control unit 22.
[0051] At the beginning, the digital camera 10 executes the simple
AF processing and AE processing so as not to exceed the prescribed
frame rate, for instance, the rate of 30 frames per second, at the
point of time to continuously drives the CCD 13 at a quick shutter
speed in consideration of the frame rate. So that the digital
camera 10 stands ready for the shutter button to be brought into
the half-depression state by repeatedly executing the following
processing. Namely, the digital camera determines whether or not
the shutter button of the key input unit 27 is brought into the
half-depression operation (step S02) while maintaining a state of a
through image display of displaying the content imaged by the CCD
13 onto the display unit 26 (step S01).
[0052] The digital camera 10 determines the fact of half-depression
of the shutter button in step S02, and then, moves the focus lens
in the imaging lens optical system 12 so as to focus on an image
center obtained at the point of that time to lock up the lens (AF
lock). On the other hand the digital camera 10 notifies the
execution of the AF lock to the user by amplifying and outputting
an electronic sound such as "peep" through a loudspeaker unit 34
(step S03).
[0053] Simultaneously, the digital camera 10 obtains an appropriate
exposure value from a state in which the automatically focused
position is locked and sets an aperture value and a shutter speed
from the exposure value to temporarily lock them (step S04).
Further, the digital camera 10 repeatedly determines whether or not
the shutter button has been fully depressed (step S05), or it has
been still in the half-depressed state or not (step S06). As the
determination results, the digital camera 10 stands ready until the
shutter will be fully depressed or the state of a half-depression
state thereof will be released, while locking each state of the AF
and AE.
[0054] The charging for the capacitor (not shown) is not limited to
the case in which it is conducted at the timing of the AE temporal
lock (step S04), it may be conducted at the timing of switch over
to the imaging mode or after the flash emission, for instance, so
as to forcedly emit the flash.
[0055] After releasing the half-depression operation of the shutter
button, the digital camera 10 determines the fact in step S06,
determines that it has not gotten to the regular imaging then
returns to the processing on and after step S01 again.
[0056] If the shutter button is fully depressed from the state
where the AF value and the AE values are locked, the digital camera
10 determines the fact in step S05, then, it determines whether or
not the emission from the flash emitting unit 35 is required from
the AE value locked in the right before step S04 (step S07).
[0057] Here, in the case in which it is determined that there is
outside light of a light amount sufficient to the object to such an
extent that the emission from the emission by the flash emitting
unit 35 is not needed, the digital camera 10 directly executes
imaging in accordance with the AF value and the AE value which have
been locked in the steps S03 and S04 without having to emit from
the flash emitting unit 35 (step S08). After quickly recording the
image data obtained through the imaging onto the built-in memory 29
or the memory card 30 followed by compressing that image data (step
S09), the digital camera 10 returns to the processing on and after
step S01 to prepare for the next imaging.
[0058] In the case in which it is determined that the emission by
the flash emitting unit 35 is necessary in step S07, the flash
driving unit 32 checks the charged state onto the capacitor (not
shown) for the emission from the flash emitting unit 35 at that
time point to output the information showing the checking result to
the control unit 22 (step S10).
[0059] FIG. 3 exemplifies a charging property to the capacitor from
the flash driving unit 32 to flash-drive the flash emitting unit
35. Here, it is supposed that it becomes possible to flash-drive
the flash emitting unit 35 when an applied voltage to the xenon
discharge tube composing of the flash emitting unit 35 due to the
electric charge amount charged in the capacitor is 220V or more.
Also it is supposed that the getting to 330V causes full charging
up to an upper limit value then the charged state is
maintained.
[0060] According to the checking result of the charged state of the
capacitor at that time point, it is determined whether or not the
charged state is enough for the flash form the flash emitting unit
35, here, whether or not the applied voltage is 220V or more (step
S11).
[0061] If it is determined that the flash emitting unit 35 has been
possible to make the flash, the digital camera 10 sets an ISO
sensitivity in response to the charged state at the time of the
checking, more specifically, sets an amplification rate to the
image signal with the analog value in the AGC/SH circuit 16 (step
S12), then, it performs the imaging by making the flash emitting
unit 35 emit with the light amount possible to be emitted at that
time point (step S13).
[0062] FIG. 4 exemplifies the content in the look-up table to which
the control unit 22 refers at that time, and in the case where the
voltage of the capacitor is set in a range of 200 to 330V; it
controls to set the ISO sensitivities in a rage of 1,600-50 step by
step to perform the imaging.
[0063] The digital camera 10 then makes the flash emitting unit 35
emit with the light amount possible to be emitted at that time
point in step S13, and after quickly recording the image data
obtained by the imaging onto the built-in memory 29 or the memory
card 30 followed by compressing the image data (step S09), then, it
returns to the processing on and after step S01 in order to prepare
the next imaging.
[0064] If it is determined that the charged state of the capacitor
by means of the flash driving unit 32 in step S11 is the state in
which the flash emitting unit 35 is disabled to emit, here, it is
determined that the applied voltage is lower than 220V, the control
unit 22 sets the ISO sensitivity to a maximum value (wherein,
1,600V as shown in FIG. 4) (step S14) then the digital camera 10
conducts the imaging without the emission from the flash emitting
unit 35 (step S15).
[0065] Then, after quickly recording the image data obtained
through the imaging onto the built-in memory 29 or the memory card
30 with the image data compressed (step S09), the digital camera 10
returns to the processing on and after step S01 to get itself ready
for the next imaging.
[0066] Like processing above mentioned, even if the capacitor to
make the flash emitting unit 35 emit that is an auxiliary light
source is not in the fully charged state, if the capacitor is
enabled to emit, the digital camera 10 determines the state. The
digital camera 10 then quickly sets so as to enhance the ISO
sensitivity, and it can shift to the imaging operation accompanied
by the emission through the flash emitting unit 35. So that, the
digital camera 10 can shift to immediate imaging after operating
the shutter button without taking time to charge the flash, and
becomes possible to execute imaging without missing any shutter
opportunity.
[0067] Even if the state of the capacitor to emit the flash
emitting unit 35 is far form its fully charged state, and it is
determined that the emission is impossible, the digital camera 10
sets the ISO sensitivity to the maximum value then shifts to the
imaging operation without a flash emission, so that it can image
without missing the shutter opportunity despite the fact that the
obtained image is affected by noise.
[0068] In the foregoing embodiment, it is assumed that every
determination of the possibility of the flash emission
corresponding to the charged state and the setting of the ISO
sensitivity are determined by referring to the look-up table stored
in the nonvolatile memory in the control unit 22 together with the
operation program.
[0069] Thereby, not only providing the enhanced sensitivity of the
imaging can be achieved quickly through the simple circuit
configuration, but also providing version up of individual
differences of each components consisting of the digital camera 10
and the product thereof become possible. Furthermore, easily
rewriting its stored contents is made possible in response to
customizing by the user.
Second Embodiment
[0070] Hereinbelow, a second embodiment in the case in which the
present invention is applied to a digital camera will be described
with reference to the drawings.
[0071] Since a conceptual configuration of an electronic circuit of
the digital camera 10 regarding the second embodiment is basically
same as that illustrated in FIG. 1, the similar units will be put
the similar reference marks and their illustration and explanation
will be omitted.
[0072] In the second embodiment, it is presumed that the imaging
lens optical system 12 or the CCD 13 has a function of a
camera-shake correcting of images due to a hand movement, more
specifically, a method for displacing an imaging light axis of the
optical system 12, or a method for moving an imaging range in an
imaging region of the CCD 13, and the like.
[0073] In addition, in a state in which an acceleration sensor (not
shown in FIG. 2) to detect the displacement of the light axis
within a frequency range of, for instance, 5 to 50 Hz to two
directions each perpendicular to the imaging light axis of the
optical system 12 is disposed and the camera-shake correcting mode
of the images due to the hand movement avoids setting differences,
it is supposed that the digital camera 10 may image sharp image
data with an affect of the camera-shake of the images due to the
hand movement avoiding.
[0074] Next to this, operations of the second embodiment will be
set forth.
[0075] Also in the digital camera 10, like the generic other
cameras, the shutter has the operation stroke of two stages and
executes imaging operations based on the operation logic as
follows. That is, as the first stage, the operation to the half
extent of the full-stroke, which locks each processed value by
executing the AF processing and the AE processing in the operation
state generally referred to as the half depression; and after this,
the full-stroke operation as the second stage, which executes
regular imaging based on the AF value and the AE value in the
operation state generally referred to as the full-depression.
[0076] FIG. 5 illustrates a content of a processing executed in the
case of imaging of a still image in an imaging mode, and the
processing is basically executed on the basis of the control by the
determining means 221 and the image control means 222 of the
control unit 22.
[0077] At the beginning, the digital camera 10 stands ready for
becoming the state of the half-depression of the shutter button
with repeated executions of the processing such that determining
whether or not the shutter button of the key input unit 27 has been
operated with the half-depression (step S22), while maintaining a
state of a through image display displaying the content imaged by
the CCD 13 on the display unit 26, by executing such simple AF
processing and AE processing that fall with a prescribed frame
rate, for instance, 30 frame/sec at that point of time, and by
continuously driving the CCD 13 at a high shutter speed with taking
account of the frame rate (step S21).
[0078] Then, in step S22, it is determined the fact of the
half-depression operation of the shutter button, the digital camera
10 moves the focus lens in the imaging lens optical system 12 so as
to focus on the center of the image obtained at that point of time
to lock the lens (AF lock). On the other hand, the digital camera
10 notifies the execution of the AF lock to the user by, for
example, amplifying and outputting the electric sound like a "peep"
sound through the loudspeaker unit 34 (step S23).
[0079] Simultaneously, the digital camera 10 obtains the
appropriate exposure value from the state of locking of the
automatically focused position and further sets the aperture value
and shutter speed from the exposure value to temporarily lock them
(step S24). The digital camera 10 then stands ready for the shutter
button to be full-depression operated or for the state of
half-depression operation to be released while locking each state
of the AF and AE by repeatedly determining whether the shutter
button is further full-depression operated or not (step S25), and
whether the half-depression operation sill maintained or not (step
S26).
[0080] If the emission from the flash emitting unit 35 is required
from the AE value temporarily locked in step S24, the flash driving
unit 32 immediately starts the charging to the capacitor (not
shown).
[0081] It is not limited for the charging to the capacitor to be
performed at the timing of the AE tentative locking (step S24), it
may be performed at timing of changeover to the imaging mode or
after the emission the flash, for instance, so as to forcibly emit
the flash.
[0082] When the half-depression operation of the shutter button is
released, the digital camera 10 determines the fact in step S26,
determines that it has not gotten to the regular imaging, and
returns to the processing on and after step S21 again.
[0083] When the shutter button is full-depression operated from the
sate in which the AF value and AE value have been locked, the
digital camera 10 determines the fact in step S25, then, it
determines whether or not the emission by the flash emitting unit
35 is required from the AE value locked in the right before step
S24 (step S27).
[0084] Here, if it is determined that outside light of a light
amount sufficient to an object is incident to the extent that the
emission from the flash emitting unit 35 is not necessary, the
digital camera 10 performs imaging in accordance with the AF value
and the AE value locked in the steps S23 and S24, respectively,
without the emission from the flash emitting unit 35 with leaving
the outside light as it is (step S28). The digital camera 10 then
returns to the processing on and after step S21 to prepare the
coming imaging after quickly recording the image data obtained
through the imaging onto the built-in memory 29 or the memory card
30 followed by compressing the image data (step S29).
[0085] In the event in which it is determined that the emission
from the flash emitting unit 35 is necessary in step S27, the flash
driving unit 32 checks the charged state to the capacitor (not
shown) to emit the flash emitting unit 35 at that point of time to
output the information showing the checking result to the control
unit 22 (step S30).
[0086] FIG. 3 exemplifies a charging property to the capacitor by
the flash driving unit 32 for flash-driving the flash emitting unit
35. Here, it is presumed that it becomes possible to flash-drive
the flash emitting unit 35 in the case in which the applied voltage
to the xenon discharge tube composing the flash emitting unit 35 is
not lower than 220V due to the electric charge amount charged to
the capacitor, and also that the capacitor will be fully charged up
to the upper limit value to maintain the charged state in the case
in which the applied voltage reaches 330V.
[0087] As the checking result of the charged state of the capacitor
at that point of time, it is determined whether or not the charged
state is possible to emit the flash emitting unit 35, here; it is
determined whether the applied voltage is not lower than 220V or
not (step S31).
[0088] If the flash emitting unit 35 determines that it enables its
emission, in addition to set the ISO sensitivity in response to the
charged state at that point of time when the check is performed,
particularly to set the amplification rate to the image signal with
the analog value in the AGC/SH circuit 16 and the shutter speed if
necessary (step S32), the digital camera 10 makes the flash
emitting unit 35 emit light with the light amount possible to be
emitted at that point of time to perform the imaging (step
S33).
[0089] If it is determined that the flash emitting unit 35 may emit
light, the digital camera 10 may make the flash emitting unit 35
emit light with the light amount possible to be emitted at that
point of time without setting the ISO sensitivity to execute the
imaging. The digital camera 10 may not determine whether the flash
emitting unit 35 is in the sate of the possibility of its emission
but may determine that the capacitor is fully charged or not.
[0090] FIG. 6 exemplifies the content of the look-up table referred
by the control unit 22 in such case, and in the case of the applied
voltage to the capacitor is in the rage of 220 to 330V, the digital
camera 10 sets the ISO sensitivities step by step in the range of
1,600 to 50. In the case of the applied voltage to the capacitor is
further higher range of 290 to 330V, the digital camera 10 sets the
shutter speeds step by step in a range of 1/15 sec to 1/60 sec to
perform the imaging.
[0091] In step S33, when emitting the flash emitting unit 35 with
the light amount possible to be flashed at that point of time to
perform the imaging, after quickly recording the image data
obtained by the imaging on the built-in memory 29 or the memory
card 30 followed by the compressing the image data (step S29), the
digital camera 10 returns to the processing on and after step S21
to prepare for the next imaging.
[0092] In step S31, if it is determined that the charged state of
the capacitor by the flash driving unit 32 is the state disabling
the flash emitting unit 35 to be flashed, wherein if it is
determined that the applied voltage is not higher than 220V, after
automatically turning on the camera-shake correcting mode of the
images due to the hand movement by the optical system 12 or the CCD
13 (step S34), the digital camera 10 sets the ISO sensitivity to
the maximum value (wherein, 1,600 as shown in FIG. 6). Further, the
digital camera 10 sets the shutter speed (S value) based on the
appropriate exposure at the ISO sensitivity value (step S35), then,
it conducts the imaging without emitting the flash emitting unit 35
(step S36).
[0093] Successively, after recording quickly the image data
obtained by the photographing onto the built-in memory 29 or the
memory card 30 followed by compressing the image data (step S29),
the digital camera 10 returns to the processing on and after step
S01 to prepare for the next imaging.
[0094] Like such a manner, in the case where the flash emitting
unit 35 that is the auxiliary light source cannot be emitted, it
becomes possible to surely image with avoiding the camera-shake of
the images due to the hand movement even in imaging by shuttering
at a low speed without the flash emission. Further, this assured
imaging can be conducted by automatically setting the camera-shake
correcting mode of the images due to the hand movement and by
setting the shutter speed to obtain the appropriate exposure in
addition to the setting of the ISO sensitivity at the maximum
value.
[0095] In the second embodiment, it is assumed that the digital
camera 10 determines all the determinations of the possibility of
the emission of the flash corresponding to the charged state and
the setting of the ISO sensitivity and of the shutter speed in a
part of the range by referring to the look-up table stored on the
nonvolatile memory in the control unit 22 together with the
operation program.
[0096] Thereby, not only providing the improved sensitivity of the
photographing can be achieved quickly through the simple circuit
configuration, but also providing version up of individual
differences of each components consisting of the digital camera 10
and the product thereof can be achieved. Furthermore, easily
rewriting its stored contents in response to customizing by the
user can be made.
Third Embodiment
[0097] In the following, referring to the drawings, a third
embodiment in the case in which the present invention is applied to
a digital camera will be explained.
[0098] Since a conceptual configuration of an electronic circuit of
the digital camera 10 regarding the third embodiment is basically
same as that illustrated in FIG. 1, the similar units will be put
the similar reference marks and their illustration and explanation
will be omitted.
[0099] Next, an operation of the third embodiment will be set
forth.
[0100] Also in the digital camera 10, like the generic other
cameras, the shutter has the operation stroke of two stages and
executes imaging operations based on the operation logic as
follows. That is, as the first stage, the operation to the half
extent of the full-stroke, which locks each processed value by
executing the AF processing and the AE processing in the operation
state generally referred to as the half depression; and after this,
the full-stroke operation as the second stage, which executes
regular imaging based on the AF value and the AE value in the
operation state generally referred to as the full-depression.
[0101] In the third embodiment, in the case of performing the flash
imaging by means of the flash emitting unit 35, if an effective
imaging distance to an object is set to, for instance, 10 m as
maximum and when imaging the object placed in a range of 10 m to an
infinitum distance, a reflective light amount enough to image and
an effect resulted from the flash emission are not expected, so
that the imaging by using the flash emitting unit 35 is not
performed.
[0102] FIG. 7 shows a content of a processing in the case of
imaging a still image in an imaging mode, and this processing is
implemented on the basis of the control through the determining
means 221 and photographing control means 222 of the control unit
22.
[0103] The digital camera 10 stands ready for bringing about the
state of the half-depression of the shutter, while maintaining a
state of a through image display displaying the content imaged by
the CCD 13 on the display unit 26, by firstly repeating executions
of a simple AF processing and AE processing that fall with a
prescribed frame rate, for instance, 30 frame/sec at that point of
time to continuously drive the CCD 13 at a high shutter speed with
taking account of the frame rate (step S41). Further, the digital
camera 10 stands ready for the state of the half-depression by
repeatedly executing the processing, in which the control unit 22
determines whether or not the shutter button has been operated with
the half-depression (step S42).
[0104] Then, in step S42, the control unit 22 determines the fact
of the half-depression operation of the shutter button, it moves
the focus lens in the imaging lens optical system 12 so as to
focusing on the center of the image obtained at that point of time
to lock the lens (AF lock). On the other hand, the control unit 22
notifies the execution of the AF lock to the user by, for example,
amplifying and outputting the electric sound like a "peep" sound
through the loudspeaker unit 34 (step S43).
[0105] Simultaneously, the control unit 22 obtains the appropriate
exposure value from the state of locking of the automatically
focused position and further sets the aperture value and shutter
speed from the exposure value to temporarily lock them (step S44).
The digital camera 10 then stands ready for the shutter to be
brought into full-depression operated or for the state of
half-depression operation to be released while locking each state
of the AF and AE by repeatedly determining whether the shutter
button is further full-depression operated or not (step S45), and
whether the half-depression operation sill maintained or not (step
S46).
[0106] If the emission from the flash emitting unit 35 is required
from the AE value temporarily locked in step S44, the flash driving
unit 32 immediately starts the charging to the capacitor (not
shown).
[0107] The charging to the capacitor (not shown) is not limited to
be performed at the timing of the AE tentative locking (step S44);
it may be performed at timing of changeover to the imaging mode or
after emitting the flash, for instance, so as to forcibly flash the
flash.
[0108] When the half-depression operation of the shutter button is
released, the digital camera 10 determines the fact in step S46,
determines that it has not gotten to the regular imaging, and
returns to the processing on and after step S41 again.
[0109] When the shutter button is full-depression operated from the
sate in which the AF value and AE value have been locked, the
digital camera 10 determines the fact in step S45. Then, it
determines whether or not the emission by the flash emitting unit
35 is required from the AE value locked in the right before step
S44 (step S47).
[0110] Here, if it is determined that outside light of a light
amount sufficient to an object is incident to the extent that the
emission from the flash emitting unit 35 is not necessary, the
digital camera 10 performs imaging in accordance with the AF value
and AE value locked in the steps S43 and S44, respectively, without
the emission from the flash emitting unit 35 with leaving the
outside light as it is (step S48). The digital camera 10 then
returns to the processing on and after step S01 to prepare the
coming imaging after quickly recording the image data obtained
through the imaging onto the built-in memory 29 or the memory card
30 (step S49).
[0111] In the event in which it is determined that the emission
from the flash emitting unit 35 is necessary in step S27, the flash
driving unit 32 checks the charged state to the capacitor (not
shown) to flash the flash emitting unit 35 at that point of time
and outputs the information showing the checking result to the
control unit 22 (step S50).
[0112] FIG. 3 exemplifies a charging property to the capacitor by
the flash driving unit 32 for flash-driving the flash emitting unit
35. Here, it is assumed that it becomes possible to flash-drive the
flash emitting unit 35 in the case in which the applied voltage to
the xenon discharge tube composing of the flash emitting unit 35 is
not lower than 220V due to the electric charge amount charged to
the capacitor. It is also assumed that that the capacitor will be
fully charged up to the upper limit value to maintain the charged
state, in the case in which the applied voltage arrives at
330V.
[0113] As the checking result of the charged state of the capacitor
at that point of time, it is determined whether or not the distance
from the AF value locked in the right before step S43 to the object
is within a range in which an effect caused from the flash emission
is not expected (10 m to infinitum distance) (step S51).
[0114] Here, if it is determined that the distance to the object is
far and the object is located in a range in which the effect
brought from the flash emission is not expected, the digital camera
10 achieves to set the enhancement of all the elements including
the ISO sensitivity other than the flash (step S52), then, performs
the imaging without making the flash emitting unit 35 flash (step
S53).
[0115] Next to such processing, after quickly compressing the image
data obtained though the imaging, the digital camera 10 quickly
records it on the built-in memory 29 or the memory card 30, then,
returns to the processing on and after step S01 to prepare for the
next imaging.
[0116] If it is determined, in step S51, that the distance up to
the object is within the range in which the effect by the flash
emission is expected, in succession to this, the digital camera 10
determines whether or not the result of checking of the charged
state in step S50 shows the charged sate in which the flash
emitting unit 35 can sufficiently emit lights wherein it determines
whether or not the results thereof shows the applied voltage that
is higher than 220V (step S54).
[0117] If the checking results shows the possibility of the
emission by the flash emitting unit 35, the digital camera 10 sets
the ISO sensitivity corresponding to the charged state at the point
of time of checking, more particularly, sets the amplification rate
to the image signal with the analog value at the AGC/SH circuit 16
in response to the distance to the object (step S56). The digital
camera 10 then performs the imaging by making flash emitting unit
35 emit light with the light amount possible to be flashed at that
point of time (step S57).
[0118] FIG. 8 exemplifies the content of the look-up table referred
by the control unit 22 in such case, and in the case of the applied
voltage to the capacitor is in the rage of 220 to 330V, the digital
camera 10 sets the ISO sensitivities step by step in the range of
1,600 to 50 to implement the imaging.
[0119] In step S57, when emitting the flash emitting unit 35 with
the light amount possible to be flashed at that point of time to
perform the imaging, after quickly recording the image data
obtained by the imaging on the built-in memory 29 or the memory
card 30 followed by the compressing the image data (step S49), the
digital camera 10 returns to the processing on and after step S41
to prepare for the next imaging.
[0120] In step S54, if it is determined that the charged state of
the capacitor by the flash driving unit 32 is the state disabling
the flash emitting unit 35 to be flashed, wherein if it is
determined that the applied voltage is lower than 220V, after
achieving to set the enhancement of sensitivity of all the elements
including the ISO sensitivity other than the flash (step S58) then
the digital camera 10 conducts the imaging without the emission
from the flash emitting unit 35 (step S59).
[0121] Next to this, after compressing the image data obtained
through the imaging, the digital camera 10 quickly records the
image data onto the built-in memory 29 or the memory card 30 (step
S49) then retunes to the processing on and after step S41 so as to
prepare the next imaging.
[0122] Like such processing, since the digital camera 10 makes the
flash in spite of insufficient state even if the flash is in the
charged state in which it cannot be flashed fundamentally and also
forces the imaging due to the automatically set achievements of the
enhancement of high sensitivity of each element, so that it may
surely image in preference to the imaging intension of the user
without missing the shutter opportunity.
[0123] In the above-mentioned first to third embodiments, having
described that the digital camera 10 copes to achieve the
enhancement of the imaging by the ISO sensitivity, particularly,
copes with the amplification rate in amplifying the analog image
signal by the AGC/SH circuit 16, the present invention is not
limited to such coping and may cope in a pixel addition method by
which additions are performed with information among adjacent
pixels to increase dynamic ranges of the pixels.
[0124] Further, a pixel addition method of a plurality of pixels,
by which a plurality of items of image data obtained through a
plurality of times of exposures continuous in terms of time are
added in pixels is possible approach.
[0125] In this case, since the image data which has been achieved
its enhancement is obtained from the image data through multiple
exposures, in the case in which the object moves intensively, even
if the function of the correcting the camera-shake of the images
due to the hand movement is operated, camera-shake is generated on
the image inevitably, so that an object with less movement is
essential, but image data higher in nature and higher in image
quality can be obtained.
[0126] Other than this, the present invention is not limited to the
aforementioned embodiments and it is possible for the invention to
be implemented in a various types of modifications within a range
not departing from the point of the invention.
[0127] Further, the forgoing embodiments include inventions in a
variety of stages; various inventions may be extracted from
appropriate combinations of a plurality of disclosed constituent
components. For instance, even if some constituent components are
deleted from all the constituent components shown in the
embodiments, at least one of the problems has been described in the
section of "problem can be solved by present invention", and in the
case in which at least one effect described in the section of the
"effect of the present invention" is obtained, the configuration
from which the some constituent components has been deleted may be
extracted as the invention.
* * * * *