U.S. patent application number 12/151447 was filed with the patent office on 2009-06-04 for imaging apparatus having focus control function.
This patent application is currently assigned to Casio Computer Co., Ltd.. Invention is credited to Masaru Onozawa.
Application Number | 20090141141 12/151447 |
Document ID | / |
Family ID | 40148285 |
Filed Date | 2009-06-04 |
United States Patent
Application |
20090141141 |
Kind Code |
A1 |
Onozawa; Masaru |
June 4, 2009 |
Imaging apparatus having focus control function
Abstract
A digital camera 1 includes a focus position table. The focus
position table, in which focus positions for person-priority pan
focus have been set, is used when a face has been detected, and the
focus position table (FIG. 2B), in which focus positions for
non-person priority pan focus have been set corresponding to the
types of non-person priority pan focus, is used when a face has not
been detected. When a face has been detected, the digital camera 1
determines the pan focus as the person-priority pan focus, and
after acquiring a focus position from the focus position table,
executes the pan focus processing. On the other hand, when a face
has not been detected, the digital camera 1 acquires, from the
focus position table, a focus position corresponding to a type of
non-person priority pan focus determined based on the photography
scene and executes the pan focus processing.
Inventors: |
Onozawa; Masaru;
(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: |
40148285 |
Appl. No.: |
12/151447 |
Filed: |
May 7, 2008 |
Current U.S.
Class: |
348/222.1 ;
348/345; 348/E5.031; 382/118 |
Current CPC
Class: |
H04N 5/23293 20130101;
H04N 5/23218 20180801; H04N 5/23219 20130101; H04N 5/232127
20180801; H04N 5/23296 20130101; G03B 13/36 20130101; G03B 15/00
20130101; H04N 5/23212 20130101; G02B 7/36 20130101; H04N 5/2357
20130101; H04N 5/232945 20180801 |
Class at
Publication: |
348/222.1 ;
382/118; 348/345; 348/E05.031 |
International
Class: |
H04N 5/228 20060101
H04N005/228; G06K 9/00 20060101 G06K009/00; G03B 13/00 20060101
G03B013/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 18, 2007 |
JP |
2007-133312 |
Claims
1. An imaging apparatus comprising: an imaging section for imaging
a photographic subject; a face detecting section for detecting a
human face from an image picked up by the imaging section; a first
focus control section for moving a focus lens to a first lens
position when a face has been detected from an image by the face
detecting section; and a second focus control section for moving a
focus lens to a second lens position which is different from the
first lens position when a face has not been detected from an image
by the face detecting section.
2. The imaging apparatus according to claim 1, wherein the face
detecting section detects a face which proportion is not less than
a predetermined percentage to the whole image picked up by the
imaging section.
3. The imaging apparatus according to claim 1, wherein the first
focus control section acquires a lens position for person-priority
as the first lens position, and moves a focus lens to the acquired
lens position for person-priority.
4. The imaging apparatus according to claim 1, wherein the first
focus control section acquires, as the first lens position, a lens
position corresponding to a size of a face detected from an image
by the face detecting section, and moves a focus lens to the
acquired lens position.
5. The imaging apparatus according to claim 4, further comprising:
a number of faces judging section for judging whether multiple
faces have been detected from an image by the face detecting
section; and a face identification section for identifying a face
which serves as a main photographic subject among the multiple
faces when judged by the number of faces judging section that
multiple faces have been detected; wherein the first focus control
section acquires, as the first lens position, a lens position
corresponding to a size of a single face detected from an image by
the face detecting section, when judged by the number of faces
judging section that multiple faces have not been detected, and
acquires, as the first lens position, a lens position corresponding
to a size of a single face which serves as a main photographic
subject identified by the face identification section when judged
by the number of faces judging section that multiple faces have
been detected.
6. The imaging apparatus according to claim 5, wherein the face
identification section identifies a face which serves as a main
photographic subject based on at least one of requirements
consisting of a size of each face, a distance from the center of
field angle to each face and a face-likeness of each face detected
from an image by the face detecting section.
7. The imaging apparatus according to claim 1, further comprising:
a photography scene judging section for judging a photography
scene; wherein the second focus control section acquires, as the
second lens position, a lens position corresponding to a
photography scene judged by the photography scene judging section,
and moves a focus lens to the acquired lens position.
8. The imaging apparatus according to claim 7, wherein the
photography scene judging section judges a photography scene based
on at least one of requirements consisting of whether shooting is
with a strobe flash, whether illumination is either one of
ultra-high illumination and ultra-low illumination, whether a
flicker has been detected, whether a light source is sunlight, and
whether an aperture is full.
9. The imaging apparatus according to claim 7, further comprising:
a determining section for determining a type of pan focus based on
a photography scene judged by the photography scene judging
section; wherein the second focus control section acquires, as the
second lens position, a lens position corresponding to a type of
pan focus determined by the determining section, and moves a focus
lens to the acquired lens position.
10. The imaging apparatus according to claim 1, further comprising:
a zoom magnification setting section for setting a zoom
magnification for zoom processing; wherein the first focus control
section acquires, as the first lens position, a lens position
corresponding to a zoom magnification set by the zoom magnification
setting section, and moves a focus lens to the acquired lens
position.
11. The imaging apparatus according to claim 1, further comprising
a zoom magnification setting section for setting a zoom
magnification for zoom processing; wherein the second focus control
section acquires, as the second lens position, a lens position
corresponding to a zoom magnification set by the zoom magnification
setting section, and moves a focus lens to the acquired lens
position.
12. The imaging apparatus according to claim 1 further comprising:
a shutter button which enables a half-depression operation and a
full-depression operation; and a first judging section for judging
whether the shutter button has been fully depressed without
stopping; wherein the first focus control section moves a focus
lens to the first lens position, when judged by the first judging
section that a shutter button has been fully depressed without
stopping and a face has been detected from an image by the face
detecting section, and the second focus control section moves a
focus lens to the second lens position when judged by the first
judging section that a shutter button has been fully depressed
without stopping and a face has not been detected from an image by
the face detecting section.
13. The imaging apparatus according to claim 12 further comprising:
an optical zoom magnification setting section for setting an
optical zoom magnification for optical zoom; and an optical zoom
magnification judging section for judging whether an optical zoom
magnification set by the optical zoom magnification setting section
is smaller than a predetermined optical zoom magnification; wherein
the first focus control section moves a focus lens to the first
lens position, when judged by the first judging section that a
shutter button has been fully depressed without stopping, it is
judged by the optical zoom magnification judging section that an
optical zoom magnification is smaller than a predetermined optical
zoom magnification, and a face has been detected from an image by
the face detecting section, and the second focus control section
moves a focus lens to the second lens position, when judged by the
first judging section that a shutter button has been fully
depressed without stopping, it is judged by the optical zoom
magnification judging section that an optical zoom magnification is
smaller than a predetermined optical zoom magnification, and a face
has not been detected from an image by the face detecting
section.
14. The imaging apparatus according to claim 12 further comprising:
a second judging section for judging whether the shutter button has
been half depressed; and an auto-focus control section for
executing auto-focus processing on a photographic subject; wherein
the auto-focus control section executes the auto-focus processing
when judged by the second judging section that a shutter button has
been half depressed.
15. The imaging apparatus according to claim 14, further
comprising: an optical zoom magnification setting section for
setting an optical zoom magnification for optical zoom; and an
optical zoom magnification judging section for judging whether an
optical zoom magnification set by the optical zoom magnification
setting section is smaller than a predetermined optical zoom
magnification; wherein the auto-focus control section further
executes the auto-focus processing when judged by the first judging
section that a shutter button has been fully depressed without
stopping, and judged by the optical zoom magnification judging
section that an optical zoom magnification is not smaller than a
predetermined optical zoom magnification.
16. The imaging apparatus according to claim 14, wherein the
auto-focus control section executes auto-focus processing on an AF
area based on a position of a face detected from an image by the
face detecting section.
17. The imaging apparatus according to claim 16 further comprising:
a number of faces judging section for judging whether multiple
faces have been detected from an image by the face detecting
section; and a face identification section for identifying a face
which serves as a main photographic subject among the multiple
faces when judged by the number of faces judging section that
multiple faces have been detected; wherein the auto-focus control
section executes auto-focus processing on an AF area based on a
position of a single face detected from an image by the face
detecting section when judged by the number of faces judging
section that multiple faces have not been detected, and executes
auto-focus processing on an AF area based on a position of a single
face which serves as a main photographic subject identified by the
face identification section when judged by the number of faces
judging section that multiple faces have been detected.
18. The imaging apparatus according to claim 14, wherein the
auto-focus control section executes auto-focus processing on an AF
area at a predetermined position when a face has not been detected
from an image by the face detecting section.
19. The imaging apparatus according to claim 14 further comprising:
an AF failure judging section for judging whether auto-focus
processing executed by the auto-focus control section has failed;
wherein the first focus control section moves a focus lens to the
first lens position when judged by the AF failure judging section
that auto-focus processing has failed and a face has been detected
from an image by the face detecting section, and the second focus
control section moves a focus lens to the second lens position when
judged by the AF failure judging section that auto-focus processing
has failed and a face has not been detected from an image by the
face detecting section.
20. The imaging apparatus according to claim 14, wherein the first
judging section judges that the shutter button has been fully
depressed without stopping when the shutter button has been fully
depressed before a lapse of predetermined time after a half
depression of the shutter button, and the second judging section
judges that the shutter button has been half depressed when the
predetermined time has passed without the shutter button being
fully depressed after a half depression of the shutter button.
21. The imaging apparatus according to claim 14, wherein the first
judging section judges that the shutter button has been fully
depressed without stopping when judged by the second judging
section that the shutter button has been fully depressed without
being judged that the shutter button has been half depressed.
22. The imaging apparatus according to claim 14 further comprising:
a third judging section for judging whether the shutter button has
been fully depressed when judged by the second judging section that
the shutter button has been half depressed; wherein the first
judging section judges that the shutter button has been fully
depressed without stopping in the case where auto-focus processing
executed by the auto-focus control section is not completed when
judged by the third judging section that the shutter button has
been fully depressed.
23. The imaging apparatus according to claim 1 further comprising:
an optical zoom magnification setting section for setting an
optical zoom magnification for optical zoom; and an optical zoom
magnification judging section for judging whether an optical zoom
magnification set by the optical zoom magnification setting section
is smaller than a predetermined optical zoom magnification; wherein
the first focus control section moves a focus lens to the first
lens position, when judged by the optical zoom magnification
judging section that an optical zoom magnification is smaller than
a predetermined optical zoom magnification and a face has been
detected from an image by the face detecting section, and the
second focus control section moves a focus lens to the second lens
position when judged by the optical zoom magnification judging
section that an optical zoom magnification is smaller than a
predetermined optical zoom magnification and a face has not been
detected from an image by the face detecting section.
24. The imaging apparatus according to claim 23 further comprising:
an auto-focus control section for executing auto-focus processing
on a photographic subject; and an optical zoom magnification
setting section for setting an optical zoom magnification for
optical zoom; and an optical zoom magnification judging section for
judging whether an optical zoom magnification set by the optical
zoom magnification setting section is smaller than a predetermined
optical zoom magnification; wherein the auto-focus control section
executes the auto-focus processing when judged by the optical zoom
magnification judging section that an optical zoom magnification is
not smaller than a predetermined optical zoom magnification.
25. A focus control method in an imaging apparatus including an
imaging section for imaging a photographic subject, comprising: a
face detecting step for detecting a human face from an image picked
up by the imaging section; a first focus control step for moving a
focus lens to a first lens position when a face has been detected
from an image by the face detecting step; and a second focus
control step for moving a focus lens to a second lens position
which is different from the first lens position when a face has not
been detected from an image by the face detecting step.
26. A computer-readable storage medium having a program of focus
control stored thereon that is executable by a computer for
controlling an imaging apparatus including an imaging section for
imaging a photographic subject, comprising: a face detecting step
for detecting a human face from an image picked up by the imaging
section; a first focus control step for moving a focus lens to a
first lens position when a face has been detected from an image by
the face detecting step; and a second focus control step for moving
a focus lens to a second lens position which is different from the
first lens position when a face has not been detected from an image
by the face detecting step.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is based upon and claims the benefit of
priority from the prior Japanese Patent Application No.
2007-133312, filed May 18, 2007, the entire contents of which is
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an imaging apparatus and a
focus control method that can be used for a digital camera having a
focus control function.
[0004] 2. Description of the Related Art
[0005] Some conventional imaging apparatuses, for example, some
digital cameras are equipped with a pan focus (deep focus) function
in addition to a standard auto focus function (for example, refer
to Japanese Laid-Open (Kokai) Patent Publication No.
2005-070738).
[0006] This pan focus function refers to a function by which a
focus lens moves to a predetermined lens position at which the
possibility that a photographic subject is focused is high, and has
advantages of easier control and shorter time for focusing than
auto focus function.
[0007] However, as a focus lens only moves to a predetermined lens
position, a situation may occur in which the photographic subject
the user truly desires to focus is not focused.
[0008] The present invention has been conceived in light of the
foregoing situations, and is to provide an imaging apparatus and a
focus control method that substantially enhance the possibility
that the photographic subject the user truly desires to focus on is
focused.
SUMMARY OF THE INVENTION
[0009] In order to achieve the above-described purpose, in
accordance with one aspect if the present invention, there is
provided an imaging apparatus comprising: an imaging section for
imaging a photographic subject; a face detecting section for
detecting a human face from an image picked up by the imaging
section; a first focus control section for moving a focus lens to a
first lens position when a face has been detected from an image by
the face detecting section; and a second focus control section for
moving a focus lens to a second lens position which is different
from the first lens position when a face has not been detected from
an image by the face detecting section.
[0010] In accordance with another aspect of the present invention,
there is provided a focus control method in an imaging apparatus
including an imaging section for imaging a photographic subject,
comprising: a face detecting step for detecting a human face from
an image picked up by the imaging section; a first focus control
step for moving a focus lens to a first lens position when a face
has been detected from an image by the face detecting step; and a
second focus control step for moving a focus lens to a second lens
position which is different from the first lens position when a
face has not been detected from an image by the face detecting
step.
[0011] In accordance with another aspect of the present invention,
there is provided a computer-readable storage medium having a
program of focus control stored thereon that is executable by a
computer for controlling an imaging apparatus including an imaging
section for imaging a photographic subject, comprising: a face
detecting step for detecting a human face from an image picked up
by the imaging section; a first focus control step for moving a
focus lens to a first lens position when a face has been detected
from an image by the face detecting step; and a second focus
control step for moving a focus lens to a second lens position
which is different from the first lens position when a face has not
been detected from an image by the face detecting step.
[0012] The above and further objects and novel features of the
present invention will more fully appear from the following
detailed description when the same is read in conjunction with the
accompanying drawings. It is to be expressly understood, however,
that the drawings are for the purpose of illustration only and are
not intended as a definition of the limits of the invention.
BRIEF DESCRIPTION OF THE DRAWING
[0013] FIG. 1 is a block diagram of a digital camera according to
an embodiment of the present invention;
[0014] FIGS. 2A and 2B shows focus position tables stored in a read
only memory (ROM) 21;
[0015] FIG. 3 is a flowchart showing an operation of a digital
camera according to a first embodiment;
[0016] FIG. 4 is a sub-flowchart showing an operation of
determination processing of priority pan focus based on a
photography scene;
[0017] FIG. 5 shows a photographic subject distance table stored in
the ROM 21;
[0018] FIG. 6A is a flowchart showing an operation of a variation
example of the first embodiment, and FIG. 6B is a flowchart showing
an operation of a main photographic subject identification
processing;
[0019] FIGS. 7A and 7B are diagrams showing face detecting frames
to be displayed;
[0020] FIG. 8 is a flowchart showing an operation of a digital
camera according to a second embodiment;
[0021] FIG. 9 is a flowchart showing an operation of a digital
camera according to the second embodiment;
[0022] FIG. 10 is a flowchart showing an operation of a digital
camera according to the second embodiment;
[0023] FIG. 11 is a flowchart showing an operation of a variation
example 1 of the second embodiment;
[0024] FIG. 12 is a flowchart showing an operation of a variation
example 3 of the second embodiment; and
[0025] FIG. 13 is a flowchart showing an operation of a variation
example 3 of the second embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0026] The present invention will hereinafter be described in
detail with reference to the preferred embodiments in which an
imaging apparatus is applied to a digital camera as an example
shown in the accompanying drawings.
A. First Embodiment
[0027] A-1. Configuration of the Digital Camera
[0028] FIG. 1 is a block diagram showing an electric schematic of a
digital camera 1 which realizes an imaging apparatus according to
the present invention.
[0029] The digital camera 1 includes an imaging lens 2 (which
includes a focus lens 2a and a zoom lens 2b), a motor driver
circuit 3, a shutter-aperture 4, a vertical driver 5, a timing
generator (TG) 6, a charge-coupled device (CCD) 7, a sample hold
circuit 8, an analog-digital converter 9, a color process circuit
10, a direct memory access (DMA) controller 11, a dynamic random
access memory (DRAM) interface 12, a dynamic random access memory
(DRAM) 13, a video random access memory (VRAM) controller 14, a
video random access memory (VRAM) 15, a digital video encoder 16,
an image display section 17, a Joint Photographic Experts Group
(JPEG) circuit 18, a digital signal processor (DSP)/central
processing unit (CPU) 19, a key input section 20, a read only
memory (ROM) 21, a strobe driver section 22, a strobe emitting
section 23, a flash memory 24 and a bus 25.
[0030] The imaging lens 2 includes the focus lens 2a, the zoom lens
2b and the like each of which includes a plurality of lens groups.
The imaging lens 2 is connected with the motor driver circuit 3.
The motor driver circuit 3 includes a focus motor, a zoom motor, a
focus motor driver and a zoom motor driver. The focus motor and the
zoom motor respectively drive the focus lens 2a and the zoom lens
2b in the optical axis direction. The focus motor driver and the
zoom motor driver respectively drive the focus lens 2a and the zoom
lens 2b in the optical axis direction in adherence to a control
signal sent from the DSP/CPU 19.
[0031] The shutter-aperture 4 includes a driver circuit not shown,
and activates the shutter-aperture in adherence to a control signal
sent from the DSP/CPU 19. The shutter-aperture functions as an
aperture and a shutter.
[0032] The aperture refers to a mechanism that controls an amount
of light that is irradiated from the imaging lens 2. The shutter
refers to a mechanism that controls a period of time during which
light is irradiated to the CCD 7. The period of time during which
light is irradiated to the CCD 7 varies depending on a speed at
which the shutter is opened and closed (that is, a shutter speed).
The exposure can be determined based on the aperture and the
shutter speed.
[0033] The CCD 7 is driven for scanning by the vertical driver 5
and the TG 6, and after photo-electrically converting the light
intensity of the respective colors in the RGB value of a
photographic subject image formed at a constant cycle, outputs them
to the sample hold circuit 8. In addition, the CCD 7 also has a
function as an electronic shutter. A shutter speed of this
electronic shutter is controlled by the DSP/CPU 19 via the vertical
driver 5 and the TG 6.
[0034] The sample hold circuit 8 performs sampling (for example,
correlated double sampling) on an analog signal sent from the CCD 7
at a frequency that is matched for the resolution of the CCD 7, and
outputs the signal to the analog-digital converter 9. In addition,
an automatic gain control (AGC) may be performed after
sampling.
[0035] The analog-digital converter 9 converts a sampled analog
signal to a digital signal, and outputs the digital signal to the
color process circuit 10.
[0036] The color process circuit 10 performs color processing
including white balance processing, interpolation processing, gamma
correction processing and the like, and generates a luminosity
color-difference signal (YUV signal) from the RGB data.
[0037] The DMA controller 11, without interposition of the DSP/CPU
19, transfers data with the DRAM 13 via the color process circuit
10 and the DRAM interface 12.
[0038] The DRAM interface 12 is a signal interface between the DMA
controller 11 and the DRAM 13, and a signal interface between the
DRAM 13 and the bus 25.
[0039] The DRAM 13, which is a type of rewritable semi conductors,
is used as not only a buffer memory that temporarily stores an
image data (that is, a YUV signal generated in the color process
circuit 10) picked up by the CCD 7 but also a working memory of the
DSP/CPU 19.
[0040] The VRAM controller 14 is a section that controls data
transfer between the VRAM 15 and the bus 25, and data transfer
between the VRAM 15 and the digital video encoder 16. Specifically,
the VRAM controller 14 is a section that controls writing of an
image data to be displayed on the VRAM 15, and reading out of the
same image data from the VRAM 15.
[0041] The VRAM 15 refers to a so called video RAM, which is a
memory that temporarily stores an image data for a through image, a
replay image or the like.
[0042] The digital video encoder 16 converts an image data in a
form of a digital signal that has been read out from the VRAM 15
into an analog signal, and sequentially outputs the signals at a
timing in accordance with the scanning method of the image display
section 17.
[0043] The image display section 17 displays an image of an image
data in a form of an analog signal is sent from the digital video
encoder 16.
[0044] The JPEG circuit 18 is a section that performs compression
and expansion of joint photographic experts group (JPEG). The JPEG
circuit 18 performs JPEG compression of an image data (YUV signal)
stored in the DRAM 13 in adherence to a control signal from the
DSP/CPU 19, and performs JPEG expansion of an image data recorded
in the flash memory 24.
[0045] The key input section 20 includes a plurality of operation
keys such as a shutter button enabling both half-depression and
full-depression, a mode selection key, zoom keys (a Wide key and a
Tele key), a SET key, and a cursor key, and outputs operational
signals that correspond to the key operations by the user to the
DSP/CPU 19.
[0046] The strobe driver section 22 drives the strobe emitting
section 23 to flash in adherence to a control signal from the
DSP/CPU 19, and the strobe emitting section 23 flashes a strobe
light. When judged that the photography scene is dark based on the
luminance component of a signal outputted from the CCD 7 or by a
photometric circuit not shown, the DSP/CPU 19 sends a control
signal to the strobe driver section 22.
[0047] Note that the flash memory 24 is a recording medium that
stores and records a compressed image data.
[0048] The DSP/CPU 19 is a one-chip microcomputer having a function
that performs zoom processing, AE processing, focus processing,
face detecting processing and the like, and controls each of the
above-described sections of the digital camera 1. In addition, the
DSP/CPU 19 includes a clock circuit which clocks date and time and
functions as a timer.
[0049] The ROM 21 stores control programs necessary for each
section of the DSP/CPU 19, that is, programs and data necessary for
various controls such as the AE processing and the focus
processing, and functions as the imaging apparatus of the present
invention by being activated in accordance with the programs.
[0050] In addition, the ROM 21 stores focus position tables for pan
focus. Note that the pan focus refers to acquiring a focus position
(that is, a focus lens position) or a photographic subject distance
without executing the auto-focus processing, and moving the focus
lens 2a to the focus position acquired or the focus position
corresponding to the photographic subject distance.
[0051] FIG. 2A shows a focus position table which is used in the
case where a face has been detected (i.e., which is used when
judged that the type of the priority pan focus is the pan focus
prioritizing a person (hereinafter referred to as a
"person-priority pan focus")). The individual focus positions for
pan focus corresponding to zoom magnifications have been set in the
table.
[0052] FIG. 2B shows a focus position table which is used in the
case where a face has not been detected (i.e., which is used when
judged that the type of the priority pan focus is a pan focus
prioritizing a photographic subject other than persons (hereinafter
referred to as a "non-person priority pan focus")). The non-person
priority pan focus is further classified into three types: a
short-distance priority pan focus, a long-distance priority pan
focus with full aperture, and a long-distance priority pan focus
without full aperture.
[0053] Focus positions for pan focus corresponding to zoom
magnifications and individual types of the non-person priority pan
focus (the short-distance priority pan focus, the long-distance
priority pan focus with full aperture, or the long-distance
priority pan focus without full aperture) have been set in the
focus position table which is used in the case where a face has not
been detected.
[0054] The focus position table shown in FIG. 2B can be considered
as a complex of focus position tables that is used for each type of
non-person priority pan focuses. In the case where a face has not
been detected, the photography scene is judged, and the focus
position table for any type of non-person priority pan focus is
used based on the judged result.
[0055] As apparent from FIG. 2A and FIG. 2B, the zoom
magnifications are classified into 7 stages: Zoom 1 to Zoom 7. Zoom
1 indicates the state in which substantially no zooming is
performed (that is, approx. 1-fold), and Zoom 7 indicates the state
in which zooming is fully performed (that is, the state in which
the zoom magnification is closed to the maximum).
[0056] The focus position for the pan focus is consequently
determined from the tables shown in FIG. 2A and FIG. 2B based on
the zoom magnification and the type of the priority pan focus (the
person-priority pan focus, the short-distance priority pan focus,
the long-distance priority pan focus with full aperture, or the
long-distance priority pan focus without full aperture).
[0057] For example, when the type of the priority pan focus is the
person-priority pan focus and the zoom magnification is Zoom 4, the
focus position at which the depth of field is 2. 2 to 7 m is
acquired. When the type of the priority pan focus is the
long-distance priority pan focus with full aperture and the zoom
magnification is Zoom 2, the focus position at which the depth of
field is 1. 7 to 8 m is acquired.
[0058] A-2. Functions of the Digital Camera 1
[0059] Functions of individual configuration featuring the digital
camera 1 in the present embodiment will hereinafter be
described.
[0060] [Operation of the Digital Camera 1]
[0061] Operation of the digital camera 1 according to a first
embodiment will hereinafter be described with reference to a
flowchart of FIG. 3.
[0062] When a pan focus shooting mode is set by user operation of
the mode selection key in the key input section 20, the DSP/CPU 19
starts imaging a photographic subject using the CCD 7, and executes
the AE processing with a focal length corresponding to the lens
position of the current zoom lens 2b. The DSP/CPU 19 also starts
image processing such as white balance processing in the color
process circuit 10 (Step S1).
[0063] When exposure, white balance and the like are set, after
starting the processing of storing an image data picked up by the
CCD 7 in the DRAM 13 (buffer memory), the DSP/CPU 19 stores the
stored image data in the VRAM 15, and starts the processing of
displaying the picked-up image data in the image display section 17
via the digital video encoder 16. That is, the DSP/CPU 19 starts a
so called through image display (Step S2).
[0064] Next, at Step S3, the DSP/CPU 19 judges whether the zoom
operation has been performed by the user. This judgment is made
based on whether an operational signal corresponding to the
operation of the zoom key (the Wide key, the Tele key) has been
sent from the key input section 20. At this time, the user performs
the operation of the Tele key when the user desires to zoom in the
photographic subject, and performs the operation of the Wide key
when the user desires to zoom out the photographic subject.
[0065] When judged at Step S3 that the zoom operation has been
performed, the DSP/CPU 19 advances to Step S4. At Step S4, the
DSP/CPU 19 executes the zoom processing in accordance with the zoom
operation, and advances to Step S5. At this time, the DSP/CPU 19
executes the zoom processing for zooming out the photographic
subject when the operation of the Wide key has been performed, and
executes the zoom processing for zooming out the photographic
subject when the operation of the Tele key has been performed.
[0066] The zoom processing may be optical zoom, electronic zoom
processing, or a combination of optical zoom and electronic zoom
processing. In the case of the optical zoom, the DSP/CPU 19 moves
the zoom lens 2b in accordance with the operation of the zoom key.
For example, the DSP/CPU 19 moves the zoom lens toward the
telescopic side when the Tele key is operated, and the DSP/CPU 19
moves the zoom lens toward the wide angle side when the Wide key is
operated. In addition, in the case of the electronic zoom
processing, the DSP/CPU 19 trims away the image data to the
trimming size in accordance with the operation of the zoom key, and
displays the trimmed image data in an enlarged form. For example,
the DSP/CPU 19 displays the trimmed image in an enlarged form by
decreasing the trimming size when the Tele key is operated, and
displays the trimmed image in an enlarged form by increasing the
trimming size when the Wide key is operated.
[0067] On the contrary, when judged at Step S3 that the zoom
operation has not been performed, it advances to Step S5 without
executing any further processing.
[0068] At Step S5, the DSP/CPU 19 judges whether the shutter button
has been half depressed by the user. This judgment is made based on
whether an operational signal corresponding to the half-depression
operation of the shutter button has been sent from the key input
section 20.
[0069] When judged at Step S5 that the shutter button has not been
half depressed, the DSP/CPU 19 returns to Step S3. On the other
hand, when judged at Step S5 that the shutter button has been half
depressed, the DSP/CPU 19 advances to Step S6. At Step S6, the
DSP/CPU 19 determines and locks the photographic conditions such as
exposure values (that is, an aperture value, a shutter speed and an
amplification factor), a white balance value and the like for the
present shooting based on a through image acquired immediately
before the half depression of the shutter button. At the same time,
the DSP/CPU 19 judges which mode, among a compulsory flash mode, an
auto-strobe mode and a flash disable mode, the strobe mode is in.
When the strobe mode is the auto-strobe mode, the DSP/CPU 19
further judges whether a luminance component of a signal outputted
from the CCD 7 (that is, the through image acquired immediately
before the half depression of the shutter button) or the image
picked up by a photometric circuit not shown is dark, and then
judges whether to flash a strobe. Thereafter, it locks the
photographic conditions such as strobe flash ON/OFF.
[0070] At subsequent Step S7, the DSP/CPU 19 acquires the present
zoom magnification.
[0071] At subsequent Step S8, the DSP/CPU 19 executes the face
detecting processing based on the image data picked up immediately
before or immediately after the half depression of the shutter
button. In other words, the DSP/CPU 19 executes the processing of
detecting whether a human face is present in the image data. This
face detecting processing detects a face which proportion to the
whole picked-up image is not less than 10% in size. In other words,
a small face which proportion to the whole picked-up image is not
less than 10% in size is detected.
[0072] As a result of this, the DSP/CPU 19 can judge whether the
user desires to shoot a person. This is because, for example, a
photographic subject having a face which proportion to the whole
image is not less than 10% in size should be located far away from
the photographer, and thus such photographic subject can be
considered as a mere passer-by, or an utterly unrelated person to
the photographer. It is common to take a photograph such that a
person the photographer desires to shoot appears with a larger face
to some extent.
[0073] Since the face detecting processing is a known art, it will
not be further explained in detail. However, the face detecting
processing may be a processing, for example, of detecting whether
an image data of a human face is present in the picked-up image by
comparing a character data of general human faces that have been
stored in advance (that is, character data on eyes, eyebrows, nose,
mouth, ears and the like), or any other processing that detects a
human face.
[0074] At subsequent Step S9, the DSP/CPU 19 judges whether a face
has been detected.
[0075] When judged at Step S9 that a face has been detected, the
DSP/CPU 19 judges that the true photographic subject the
photographer desires to shoot is a person, and advances to Step
S10. At Step S10, the DSP/CPU 19 determines that the type of the
priority pan focus is the person-priority pan focus. As a result of
this, the DSP/CPU 19 acquires a focus position for the pan focus
using the focus position table shown in FIG. 2A.
[0076] When determined that the type of the priority pan focus is
the person-priority pan focus, the DSP/CPU 19 advances to Step S11.
At Step S11, the DSP/CPU 19 acquires a focus position for
prioritizing a person from the focus position table shown in FIG.
2A based on the zoom magnification acquired at Step S7, and
advances to Step S14. That is, when a face which proportion to the
whole picked-up image is not less than 10% in size has been
detected, in other words, when a person is present within a
predetermined distance from the photographer (that is, the digital
camera 1), the DSP/CPU 19 acquires the pan focus position for
prioritizing a person. Thereby, it is possible to acquire the focus
position for the pan focus at which a person who is present within
a predetermined distance from the photographer and who is the true
photographic subject the photographer desires to shoot is focused,
and it is possible to focus on the photographic subject
quickly.
[0077] Only the lower limit of proportion (10% in this case) of a
face size to the whole picked-up image is given in this case, but
both upper and lower limits of the proportion may be given. It is
possible to confine the distance from the photographer to the
person who serves as a photographic subject by setting the
detecting processing to detect only a face which proportion to the
whole image from 10% to 30%, for example, in size. It is possible
to acquire the focus position for the pan focus at which a person
is focused with higher accuracy by recording the pan focus position
corresponding to the confined distance in the focus position
table.
[0078] On the contrary, when judged at Step S9 that a face has not
been detected, the DSP/CPU 19 determines that the type of the
priority pan focus is the non-person priority pan focus, and
advances to Step S12. At Step S12, the DSP/CPU 19 executes the
determination processing of the type of the non-person priority pan
focus based on the photography scene. Specifically, the DSP/CPU 19
judges the present photography scene, and determines the type of
the non-person priority pan focus based on this photography scene.
The determination processing will be described later.
[0079] When a face has not been detected, the DSP/CPU 19 acquires a
focus position using the focus position table as shown in FIG. 2B.
Focus positions differ depending on the types of the non-person
priority pan focus (that is, whether the type of the non-person
priority is the short-distance priority pan focus, the
long-distance priority pan focus with full aperture, or the
long-distance priority pan focus without full aperture), therefore
the DSP/CPU 19 need to determine the type of the non-person
priority pan focus based on the photography scene.
[0080] Subsequently, the DSP/CPU 19 advances to Step S13. At Step
S13, the DSP/CPU 19 acquires the focus position for the pan focus
from the focus position table shown in FIG. 2B based on the type of
the non-person priority pan focus determined by the determination
processing at Step S10 and the zoom magnification acquired at Step
S7, and advances to Step S14.
[0081] Suppose the case where the type of the priority pan focus is
determined as the short-distance priority pan focus and the zoom
magnification acquired is Zoom 3. In this case, the DSP/CPU 19
acquires the focus position at which the depth of field is 1.5 to
5.2 m.
[0082] At Step S14, it moves the focus lens 2a to the pan focus
position it has acquired by sending a control signal to the motor
driver circuit 3.
[0083] At subsequent Step S15, the DSP/CPU 19 judges whether the
shutter button has been fully depressed by the user. This judgment
is made based on whether an operational signal corresponding to the
full-depression operation of the shutter button has been sent from
the key input section 20.
[0084] When judged at Step S15 that the shutter button has not been
fully depressed, the DSP/CPU 19 remains at Step S15 until the
shutter button is fully depressed. Then, when judged that the
shutter button has been fully depressed, the DSP/CPU 19 advances to
Step S16. At Step S16, the DSP/CPU 19 executes the still image
shooting processing under the photographic conditions locked at
Step S6, and records a still image data compressed by the JPEG
circuit 18 in the flash memory 24.
[0085] Next, the determination processing of the priority pan focus
based on the photography scene will be described with reference to
a sub-flowchart of FIG. 4.
[0086] In this case, the DSP/CPU 19 judges the photography scene
based on the judgment on whether the shooting is with a strobe
flash, whether the illumination is either one of ultra-high
illumination and ultra-low illumination, whether a flicker has been
detected, whether a light source is sunlight and whether an
aperture is full. Then, based on this photography scene, the
DSP/CPU 19 executes the determination processing on whether the
type of pan focus is the short-distance priority pan focus, the
long-distance priority pan focus with full aperture, or the
long-distance priority pan focus without full aperture.
[0087] When advanced to Step S12 in FIG. 3, The DSP/CPU 19 then
advances to Step S21 in FIG. 4. At Step S21, the DSP/CPU 19 judges
whether the shooting is with a strobe flash. The judgment is made
based on the photographic conditions locked at Step S6 in FIG.
3.
[0088] When judged at Step S12 that the shooting is with a strobe
flash, the DSP/CPU 19 advances to Step S25. On the other hand, when
judged that the shooting is not with a strobe flash, the DSP/CPU 19
advances to Step S22.
[0089] When judged that the shooting is not with a strobe flash and
advanced to Step S22, the DSP/CPU 19 judges whether the
illumination is either one of ultra-high illumination and ultra-low
illumination based on the photographic conditions locked at Step S6
in FIG. 3 (or the through image acquired when the shutter button
has been half depressed). When judged that the illumination is
either one of ultra-high illumination and ultra-low illumination,
the DSP/CPU 19 advances to Step S26. On the other hand, when judged
that the illumination is not ultra-high illumination or ultra-low
illumination, the DSP/CPU 19 advances to Step S23. This judgment on
ultra-high illumination and ultra-low illumination is made based on
the quantity of electric charge into which light irradiated to the
CCD 7 has been converted.
[0090] When judged that the illumination is not either ultra-high
illumination or ultra-low illumination and advanced to Step S23,
the DSP/CPU 19 judges whether a flicker has been detected in a
through image acquired when the shutter button has been half
depressed. When judged that a flicker has been detected, the
DSP/CPU 19 advances to Step S25, and when judged that a flicker has
not been detected, it advances to Step S24.
[0091] When judged that a flicker has not been detected and
advanced to Step S24, the DSP/CPU 19 judges whether a light source
is sunlight. This judgment is made based on the white balance among
the photographic conditions locked at Step S6. Specifically, when
judged that a color temperature of a light source of light acquired
by the automatic white balance processing in the color process
circuit 10 is the color temperature of sunlight, the light source
is judged to be sunlight. On the other hand, when judged that a
color temperature of a light source of light acquired by the
automatic white balance processing is not the color temperature of
the sunlight, the light source is judged to be other than sunlight
(fluorescent lighting, incandescent lighting or the like). When
judged at Step S24 that the light source is not sunlight, it
advances to Step S25. On the other hand, when judged that the light
source is sunlight, it advances to Step S26.
[0092] The DSP/CPU 19 determines that the type of the priority pan
focus is the short-distance priority pan focus (Step S25), when
judged at Step S21 that the shooting is with a strobe flash, when
judged at Step S23 that a flicker has been detected, or when judged
at Step S24 that a light source is not sunlight.
[0093] On the contrary, the DSP/CPU 19 advances to Step S26, when
judged at Step S22 that the illumination is either one of
ultra-high illumination and ultra-low illumination, or when judged
at Step S24 that the light source is sunlight. At Step S26, the
DSP/CPU 19 judges whether the aperture is full. This judgment is
made based on the photographic conditions locked at Step S6.
[0094] When judged at Step S26 that the aperture is full, the
DSP/CPU 19 determines that the type of the priority pan focus is
the long-distance priority pan focus with full aperture (Step S27).
On the other hand, when judged that the aperture is not full, the
DSP/CPU 19 determines that the type of the priority pan focus is
the long-distance priority pan focus without full aperture (Step
S28).
[0095] After the determination of the priority pan focus, the
DSP/CPU 19 advances to Step S13 in FIG. 3.
[0096] As described above, the DSP/CPU 19 determines the type of
the priority pan focus based on the photography scene.
[0097] In this case, the face detecting processing and the priority
pan focus determination processing based on the photography scene
are executed after a half depression of the shutter button.
Instead, the face detecting processing may be executed periodically
while the through image is being displayed before a half depression
of the shutter button. Alternatively, both the face detecting
processing and the priority pan focus determination processing
based on the photography scene may be executed periodically.
Thereby, it is possible to execute the pan focus processing quickly
after a half depression of the shutter button.
[0098] As described so far above, in the first embodiment, when a
face is detected, the DSP/CPU 19 judges that the true photographic
subject the photographer desires to shoot is a person, and executes
the pan focus processing using the focus position table for the
person-priority pan focus (that is, the focus position table as
shown in FIG. 2A). On the other hand, when a face is not detected,
the DSP/CPU 19 judges that the true photographic subject the
photographer desires to shoot is a landscape or the like, and
executes the pan focus processing using the focus position table
for the background-priority pan focus (that is, the focus position
table as shown in FIG. 2B). Accordingly, it is possible to focus
appropriately and quickly corresponding to the photographic subject
to shoot. In addition, it is possible to substantially enhance the
possibility that the true photographic subject is focused in the
pan focus processing.
[0099] Furthermore, the DSP/CPU 19 verifies the zoom magnification
when executing the pan focus processing. Accordingly, it is
possible to execute the pan focus processing on the true
photographic subject appropriately, and therefore it is possible to
substantially enhance the possibility that the true photographic
subject is focused in the pan focus processing.
[0100] Furthermore, the DSP/CPU 19 can detect truly desired
photographic subject since the DSP/CPU 19 does not detect a face
which size is less than 10% of the whole picked-up image in size.
Specifically, since a small face which proportion is less than 10%
in size is located far away from the photographer, and such face is
not considered as the photographic subject the user truly desires
to shoot but is considered as a mere passer-by who does not have
any relation to the photographer, and thus such face can be
considered as a part of the landscape.
[0101] Furthermore, when a face has not been detected, the DSP/CPU
19 determines the type of the non-person priority pan focus based
on the photography scene, and executes the pan focus processing
using the focus position table for the non-person priority pan
focus of the type determined. Accordingly, it is possible to
appropriately and quickly execute the pan focus processing
corresponding to the photography scene. In addition, it is possible
to execute the pan focus processing with high accuracy on a
photographic subject other than a person, for example, a landscape
or the like. In addition, it is possible to substantially enhance
the possibility that the true photographic subject is focused in
the pan focus processing.
B. A Variation Example of the First Embodiment
[0102] The following variation example of the first embodiment as
described above is possible.
[0103] In the above-described first embodiment, when a face which
proportion to the whole picked-up image in size is not less than
10% is detected, the DSP/CPU 19 determines that the type of the
priority pan focus is the person-priority pan focus, and acquire
the focus position based on only the zoom magnification from the
pan focus table for person-priority pan focus. Instead, in the
present variation example, the focus position is changed based on
the size of the detected face or the like.
[0104] In the present variation example, in place of the focus
position table shown in FIG. 2A, the photographic subject distance
table as shown in FIG. 5 has been recorded in the ROM 21. The
individual photographic subject distances corresponding to the size
of the face detecting frame and the zoom magnification have been
set in this photographic subject distance table. The face detecting
frame will be described later.
[0105] The operation of the present variation example will
hereinafter be described with reference to the flowchart of FIG.
6A.
[0106] When determined at Step S10 in FIG. 3 that the type of the
priority pan focus is the person-priority pan focus, the DSP/CPU 19
advances to Step S51 in FIG. 6A. At FIG. 6A, the DSP/CPU 19 judges
whether multiple faces have been detected by the face detecting
processing at Step S6 in FIG. 3.
[0107] When judged at Step S51 that multiple faces have not been
detected, that is, when judged that only a single face has been
detected, the DSP/CPU 19 advances to Step S52. At Step S52, the
DSP/CPU 19 displays the face detecting frame based on a zone of the
detected face.
[0108] FIG. 7A and FIG. 7B are diagrams showing the face detecting
frames that are displayed. FIG. 7A is a diagram showing a face
detecting frame 31 that is displayed when a single face has been
detected.
[0109] It is apparent from FIG. 7A that the face detecting frame 31
is displayed on faces detected in the image displayed (picked
up).
[0110] This face detecting frame 31 is displayed in a size
corresponding to the zone of the detected face. That is, when the
zone of the detected face is small, the face detecting frame 31 is
displayed in a small size, and when the zone of the detected face
is large, the face detecting frame 31 is displayed in a large
size.
[0111] At subsequent Step S53, the DSP/CPU 19 acquires the
photographic subject distance from the photographic subject
distance table based on the size of the face detecting frame 31
displayed corresponding to the zone of the detected face (face
size) and the zoom magnification it has acquired, and advances to
Step S57. The size of the face detecting frame 31 is determined
corresponding to the zone of the detected face, and thus the
photographic subject distances corresponding to the size of the
face detecting frame 31 recorded in the photographic subject
distance table and the zoom magnification should be the
photographic subject distances recorded corresponding to the size
of the detected face and the zoom magnification. This is because
the distances from the faces to the photographer (the digital
camera 1) differs depending on the size of the detected face and
the zoom magnification. For example, in the case where the zoom
magnifications are the same, if the photographic subject distance
when the size of the face detecting frame 31 is large is compared
to the photographic subject distance when the size thereof is
small, the photographic subject distance when the size thereof is
large should be shorter. In the meantime, in the case where the
sizes of the face detecting frames 31 are the same, if the
photographic subject distance when the zoom magnification is large
is compared to the photographic subject distance when it is small,
the photographic subject distance when the zoom magnification is
small should be shorter.
[0112] In the photographic subject distance table, the individual
photographic subject distances are set corresponding to the size of
the face detecting frame 31 and the zoom magnification. However,
the photographic subject distances may be set corresponding to the
size of the face and the zoom magnification. Furthermore, the
photographic subject distance is set in the photographic subject
distance table in this embodiment. However, the focus positions may
be set as in the first embodiment described above.
[0113] On the contrary, when judged at Step S51 that multiple faces
have been detected, the DSP/CPU 19 advances to Step S54. At Step
S54, the DSP/CPU 19 executes main photographic subject
identification processing of identifying a face which serves as the
main photographic subject among the multiple faces detected. The
main photographic subject identification processing will be
described later. Briefly, the main photographic subject
identification processing identifies the main photographic subject
through comprehensive comparison of the distance from the center of
the field angle to the face, the area of the face, and
face-likeness.
[0114] After identifying the main photographic subject through the
main photographic subject identification processing, the DSP/CPU 19
advances to Step S55. At Step S55, the DSP/CPU 19 displays the
individual face detecting frames 31 based on the zones of the
detected faces and distinctly displays the main photographic
subject identified by the main photographic subject identification
processing. Also in this case, the face detecting frames 31 are
displayed in the sizes corresponding to the zones of the detected
faces.
[0115] FIG. 7B is a diagram showing the face detecting frames that
are displayed when multiple faces are detected and the main
photographic subject distinctly displayed.
[0116] It is apparent from FIG. 7B that the face detecting frames
31 are displayed on the detected multiple faces (a face of a person
32, a face of a person 33 and a face of a person 34) in the
displayed (picked-up) image. It is also apparent that the face of
the person 33 is identified as the main photographic subject, and
the main photographic subject is displayed such that it is
differentiated from the other photographic subjects. (That is, the
face detecting frame 31 is displayed with the thick frame). In this
embodiment, the main photographic subject is distinctly displayed
by displaying the face detecting frame 32 with a thick frame. In
place of this, the main photographic subject may be distinctly
displayed by changing the type of lines (such as dotted line,
dashed line), the color or the like of the face detecting frame 31.
Alternatively, the information that the photographic subject is the
main photographic subject may be displayed separately from the face
detecting frame 31.
[0117] Subsequently, the DSP/CPU 19 advances to Step S56, where the
DSP/CPU 19 acquires the photographic subject distance from the
photographic subject distance table based on the size of the face
detecting frame 31 displayed corresponding to the zone of the face
(the face size) identified as the main photographic subject and the
zoom magnification acquired, and advances to Step S57.
[0118] When advanced to Step S57, the DSP/CPU 19 acquires the focus
position corresponding to the photographic subject distance
acquired using a photographic subject distance/focus position
conversion table not shown, and moves the focus lens 2a to the
focus position acquired. Then, the DSP/CPU 19 advances to Step S15
in FIG. 3.
[0119] As described above, the DSP/CPU 19 acquires the photographic
subject distance (focus position) based on the size of the detected
face and the zoom magnification. Thereby, it is possible to quickly
focus on a person with high accuracy, and the possibility that the
true photographic subject is focused in the pan focus processing is
substantially enhanced.
[0120] In addition, when multiple faces have been detected, the
DSP/CPU 19 identifies the face which serves as the main
photographic subject and acquires the photographic subject distance
based on the size of the face identified as the main photographic
subject and the zoom magnification. Thereby, it is possible to
quickly focus on the main photographic subject with high accuracy,
and the possibility that the true photographic subject is focused
in the pan focus processing is substantially enhanced.
[0121] Next, the operation of the main photographic subject
identification processing will be described with reference to a
sub-flowchart of FIG. 6B.
[0122] When advanced to Step S54 in FIG. 6A, the DSP/CPU 19
advances to Step S71 in FIG. 6B, where the DSP/CPU 19 acquires the
distance D0 from the center of the field angle to the diagonal
points. This distance D0 from the center of the field angle to the
diagonal points is determined depending on the size of the image to
be picked up.
[0123] At subsequent Step S72, the DSP/CPU 19 calculates the
distance Df from the center of the field angle of each detected
face.
[0124] At subsequent Step S73, the DSP/CPU 19 calculates the area S
of the zone of each detected face. Note that, the area S may be an
area of the face detecting frame 31 of each face. This is because
the face detecting frame 31 has a size corresponding to the zone of
the face.
[0125] At subsequent Step S74, the DSP/CPU 19 calculates the
face-likeness amount F of each detected face. In this embodiment,
the DSP/CPU 19 detects a face, for example, through comparison of
general character data of a human face (the character data on eyes,
eyebrows, nose, mouth, ears and the like) with the image data, and
when the face-likeness amount is within a predetermined error
range, determines a face as the true face. Therefore, the smaller
the error is, the larger the face-likeness amount F should be.
[0126] At subsequent Step S75, the DSP/CPU 19 calculates the
evaluation value T for each face based on D0, Df, S, F that have
been acquired and calculated at Step S71 to Step S74. The
calculation can be made using the following calculating
formula:
Evaluation value T=(a-Df/D0)+S.times..beta.+F.times..gamma.,
[0127] where, a is a distance weighing coefficient, B is an area
weighing coefficient, and .gamma. is a face-likeness weighing
coefficient.
[0128] In this calculation formula, the evaluation value T should
be larger, the closer to the center of the field angle the face is,
the larger the area of the face is, and the more face-likeness the
face has. This is because the photographic subject the photographer
desires to shoot tends to be close to the center of the field angle
and to be picked up with a larger face. In addition, since a
photographic subject with low face-likeness is not likely a face or
is likely a face of a photographic subject located far away, the
photographic subject can be judged as not the photographic subject
the photographer truly desires to shoot.
[0129] At subsequent Step S76, the DSP/CPU 19 identifies the face
with the highest evaluation value T of all calculated evaluation
values T as the main photographic subject, and advances to Step S55
in FIG. 6A.
[0130] As described above, when multiple faces are detected, the
distance from the center of the field angle to the face, the area
of the face, and the face-likeness are compared comprehensively.
Thereby, it is possible to quickly identify the face which serves
as the main photographic subject, that is, the photographic subject
the photographer truly shot from the multiple faces detected, and
thus it is possible to quickly focus on the photographic subject
the photographer truly shot.
[0131] On the contrary, in a conventional art, even when multiple
faces are detected, it is not determined which face should be
focused, and thus the photographic subject the user truly shot are
not identified. Additionally, in a conventional art, the focus
processing is executed on one of the detected multiple faces or all
detected faces, and thus it is impossible to focus on the
photographic subject the user truly desires to shoot.
[0132] Alternatively, another approach may also be conceivable, in
which the character data on specific faces such as those of the
friends or the family members of the user are registered, and when
multiple faces are detected, the registered face is identified as
the main photographic subject through personal authentication
processing, and the focus processing is executed on it. However, as
the registration of the faces of the specific persons is required
and a long processing time is required for the personal
authentication, it is not possible to quickly identify the main
photographic subject.
[0133] In the present variation example, however, when multiple
faces are detected, the main photographic subject is identified
through comprehensive comparison of the distance from the center of
the angle of field to the face, the area of the face, and the
face-likeness so as to quickly and easily focus on the true
photographic subject.
[0134] Specifically, it is common that the user puts the
photographic subject the user truly desires to shoot in the
vicinity of the center of the angle of field, and it is not
conceivable that the user shoots the true photographic subject with
a small size. Therefore, the example variation identifies the main
photographic subject verifying the closeness from the center of the
angle of field and the face size. In addition, since a photographic
subject with low face-likeness is not likely a face or is likely a
face of a photographic subject located far away, the variation
example also identifies the main photographic subject verifying
face-likeness.
C. The Second Embodiment
[0135] The second embodiment will hereinafter be described.
[0136] In the first embodiment, the pan focus processing is
executed when the pan focus shooting mode is set by the user. In
the second embodiment, however, the pan focus processing is
executed when the shutter button is fully depressed without
stopping in the auto focus shooting mode. In the case where the
shutter button has been fully depressed without stopping, it is
likely that the user truly desires to shoot. Accordingly, the pan
focus processing is executed to reduce the focus processing
time.
[0137] [The Operation of the Digital Camera 1]
[0138] The second embodiment realizes the imaging apparatus
according to the present invention also through use of the digital
camera 1 having a similar structure as the structure shown in FIG.
1. In the second embodiment, the optical zoom is used to execute
the zoom processing.
[0139] The operation of a digital camera 1 according to a second
embodiment will hereinafter be described with reference to the
flowchart of FIG. 8 to FIG. 10.
[0140] When the auto focus shooting mode is set by user operation
of the mode selection key in the key input section 20, the DSP/CPU
19 starts imaging a photographic subject using the CCD 7, and
executes the AE processing with a focal length corresponding to the
lens position of the current zoom lens 2b. the DSP/CPU 19 also
starts the processing on the images such as the white balance
processing in the color process circuit 10 (Step S101).
[0141] Next, the DSP/CPU 19 sets exposure, white balance and the
like, and then starts a so called through image display. In the
through image display, after storing an image data picked up by the
CCD 7 in the DRAM 13, the DSP/CPU 19 stores the stored image data
in the VRAM 15, and display the image data picked up in the image
display section 17 via the digital video encoder 16 (Step
S102).
[0142] Next, at Step S103, the DSP/CPU 19 starts the face detecting
processing of sequentially detecting whether a face of a human is
present in the picked-up image data. As explained in the
above-described first embodiment, the face detecting processing
detects a face which proportion to the whole picked-up image is not
less than 10% in size.
[0143] At subsequent Step S104, the DSP/CPU 19 starts the
processing of overlapping the face detecting frame 31 on the
detected face in the through image. In the display processing, it
should be understood that when a face is detected, the face
detecting frame 31 is displayed based on the zone of the detected
face, and when a face is not detected, the face detecting frame 31
is not displayed. As explained in the above-described variation
example of the first embodiment, the face detecting frame 31 is
displayed in the size corresponding to the zone of the detected
face.
[0144] Subsequently, the DSP/CPU 19 judges at Step S105 whether the
zoom operation has been performed by the user.
[0145] When judged at Step S105 that the zoom operation has been
performed, the DSP/CPU 19 advances to Step S106. At Step S106, the
DSP/CPU 19 executes the zoom processing in accordance with the
operation, and advances to Step S107.
[0146] On the other hand, when judged at Step S105 that the zoom
operation has not been performed, the DSP/CPU 19 advances to Step
S107 without executing any further processing.
[0147] When advanced to Step S107, the DSP/CPU 19 judges whether
multiple faces have been detected by the face detecting
processing.
[0148] When judged at Step S107 that multiple faces have been
detected, the DSP/CPU 19 advances to Step S108. At Step S108, the
DSP/CPU 19 executes the main photographic subject identification
processing of identifying the face which serves as the main
photographic subject among the detected multiple faces. As
explained in the above-described first embodiment, the main
photographic subject identification processing executes the
operation as shown in the flowchart of FIG. 6B.
[0149] At subsequent Step S109, the DSP/CPU 19 distinctly displays
the face of the identified main photographic subject, and advances
to Step S110. In this embodiment, as shown in FIG. 7B, the DSP/CPU
19 distinctly displays the face by displaying the face detecting
frame 31 with a thick frame. However, it should be understood that
the face may be distinctly displayed in other methods.
[0150] On the contrary, when judged that multiple faces have not
been detected at Step S107 (including when no face has been
detected), the DSP/CPU 19 advances to Step S110 without executing
any further processing.
[0151] When advanced to Step S110, the DSP/CPU 19 judges whether
the shutter button has been half depressed by the user.
[0152] When judged at Step S110 that the shutter button has not
been half depressed, the DSP/CPU 19 returns to Step S105. On the
other hand, when judged at Step S110 that the shutter button has
been half depressed, the DSP/CPU 19 advances to Step S111. At Step
S111, the DSP/CPU 19 determines and locks the photographic
conditions such as the exposure values (the aperture value, the
shutter speed and the amplification factor), the white balance
value and the like for the present shooting based on the through
image acquired immediately before the half depression of the
shutter button. At the same time, the DSP/CPU 19 judges which mode,
among the compulsory flash mode, the auto-strobe mode and the flash
disable mode, the strobe mode is in. When the strobe mode is the
auto-strobe mode, the DSP/CPU 19 further judges whether a luminance
component of a signal outputted from the CCD 7 (that is, the
through image acquired immediately before the half depression of
the shutter button) or the image picked up by a photometric circuit
not shown is dark. Then, after judging whether to flash a strobe,
the DSP/CPU 19 locks the photographic conditions such as strobe
flash ON/OFF.
[0153] Subsequently, the DSP/CPU 19 judges at Step S112 whether a
face has been detected immediately before the half depression of
the shutter button.
[0154] When judged at Step S112 that a face has been detected, the
DSP/CPU 19 advances to Step S113, where the DSP/CPU 19 judges
whether multiple faces have been detected.
[0155] When judged at Step S113 that multiple faces have been
detected, the DSP/CPU 19 advances to Step S114. At Step S114, the
DSP/CPU 19 sets the AF area at the position of the face identified
as the main photographic subject immediately before the half
depression of the shutter button, and after starting the AF
processing according to the contrast detection method based on the
image data of the AF area set, advances to Step S117 in FIG. 9.
[0156] The AF processing according to the contrast detection method
refers to the AF processing as follows: A control signal is sent to
the motor driver circuit 3 so that the search movement of the focus
lens 2a from one lens end to the other lens end is performed within
a range in which the lens can be driven, and when the lens position
at which the contrast of the image data in the AF area has a peak
value is detected, the search movement is completed and the focus
lens 2a is moved to the detected lens position with the peak
contrast for focusing.
[0157] On the contrary, when judged at Step S113 that multiple
faces have not been detected, that is, when judged that a single
face has been detected, the DSP/CPU 19 advances to Step S115. At
Step S115, the DSP/CPU 19 sets the AF area at the position of the
detected face, and after starting the AF processing according to
the contrast detection method based on the image data set, advances
to Step S117 in FIG. 9.
[0158] On the contrary, when judged at Step S112 that a face has
been detected, the DSP/CPU 19 advances to Step S116. At Step S116,
the DSP/CPU 19 sets the AF area at the center of the field angle,
and after starting the AF processing according to the contrast
detection method based on the image data of the AF area set,
advances to Step S117 in FIG. 9.
[0159] When advanced to Step S117, the DSP/CPU 19 judges whether
the AF processing has been completed. It should be understood that
the AF processing is judged to be completed when the focus lens 2a
has been moved to the lens position at which the detected contrast
has a peak value, and when the lens position at which a contrast
has a peak value has not been detected and the search movement of
the focus lens 2a from one lens end to the other lens end has been
completed.
[0160] When judged at Step S117 that the AF processing has not been
completed, the DSP/CPU 19 advances to Step S118, where the DSP/CPU
19 judges whether the shutter button has been fully depressed by
the user.
[0161] When judged at Step S118 that the shutter button has not
been fully depressed, the DSP/CPU 19 returns to Step S117.
[0162] On the other hand, when judged at Step S118 that the shutter
button has been fully depressed before the judging at Step S117
that the AF processing has been completed, the DSP/CPU 19 judges
that the user is requesting the quick shooting, and advances to
Step S119 to judge whether to execute the pan focus processing. The
cases where the shutter button is fully depressed before the AF
processing is completed includes the case where the shutter button
has been fully depressed without stopping by the user, and the
like.
[0163] The AF processing continues even when advanced to Step
S119.
[0164] When advanced to Step S119, the DSP/CPU 19 acquires the zoom
magnification for the present optical zoom.
[0165] Subsequently, the DSP/CPU 19 judges at Step S120 whether the
zoom magnification for the present optical zoom acquired is within
the range from 1-fold (that is, the magnification on the Wide side)
to a predetermined magnification.
[0166] When judged at Step S120 that the present zoom magnification
is not within the range from 1-fold to a predetermined
magnification, that is, when judged that the present zoom
magnification is larger than a predetermined magnification, the
DSP/CPU 19 advances to Step S121. At Step S121, the DSP/CPU 19
judges whether the AF processing has been completed. When judged
that the AF processing has not been completed, the DSP/CPU 19
remains at Step S121 until judged that the AF has been
completed.
[0167] When the shutter button has been fully depressed before the
completion of the AF processing, the DSP/CPU 19 executes the AF
processing without executing the pan focus processing although the
quick shooting is being requested. This is because, when the zoom
magnification of the optical zoom is larger than a predetermined
magnification, the depth of field is reduced, and the photographic
subject is likely to be out of focus if the pan focus processing is
executed. Therefore, when the zoom magnification is larger than a
predetermined magnification, shooting is suspended until the AF
processing is completed although it takes a long time for the focus
processing. As a result of this, it is possible to focus on the
true photographic subject appropriately.
[0168] When judged at Step S121 that the AF processing has been
completed, the DSP/CPU 19 advances to Step S122, where the DSP/CPU
19 judges whether the AF processing has failed. The AF processing
is judged as the failure in the case where the DSP/CPU 19 fails to
detect the lens position where the contrast has a peak value before
the search movement from one lens end to the other lens end of the
focus lens 2a is completed. That is, the DSP/CPU 19 judges as the
failure in the case where the DSP/CPU 19 fails to detect the
focusing lens position.
[0169] When judged at Step S122 that the AF processing has not
failed, the DSP/CPU 19 advances to Step S129. At Step S129, the
DSP/CPU 19 executes the still image shooting processing under the
photographic conditions locked at Step S111, and records the still
image data compressed by the JPEG circuit 18 in the flash memory
24.
[0170] On the other hand, when judged at Step S122 that the AF
processing has failed, the DSP/CPU 19 advances to Step S123 to move
to the pan focus processing.
[0171] In the meantime, when judged at Step S120 that the present
zoom magnification is within the range from 1-fold to a
predetermined magnification, the DSP/CPU 19 advances to Step S123
to move to the pan focus processing. At this time, the DSP/CPU 19
may forcibly terminate the AF processing according to the contrast
detection method.
[0172] When advanced to Step S123, the DSP/CPU 19 judges whether a
face has been detected immediately before the half depression of
the shutter button.
[0173] When judged at Step S123 that a face has been detected, the
DSP/CPU 19 advances to Step S124, where the DSP/CPU 19 determines
the type of the priority pan focus as the person-priority pan
focus. As a result of this, the DSP/CPU 19 acquires a focus
position for the pan focus using the focus position table shown in
FIG. 2A.
[0174] Next, when determined that the type of the priority pan
focus is the person-priority pan focus, the DSP/CPU 19 advances to
Step S125. At Step S125, the DSP/CPU 19 acquires a focus position
for prioritizing a person from the focus position table shown in
FIG. 2A based on the zoom magnification acquired at Step S119, and
advances to Step S128.
[0175] On the other hand, when judged at Step S123 that a face has
been detected, the DSP/CPU 19 advances to Step S126, where the
DSP/CPU 19 executes the determination processing of the type of the
priority pan focus based on the photography scene. In the
determination processing, the DSP/CPU 19 performs the operation as
shown in the flowchart of FIG. 4, as explained in the
above-described first embodiment.
[0176] Next, after determining the type of the priority pan focus
based on the photography scene, the DSP/CPU 19 advances to Step
S127. At Step S127, the DSP/CPU 19 acquires the focus position for
the pan focus from the focus position table shown in FIG. 2B based
on the type of the priority pan focus determined by the
determination processing and the zoom magnification acquired at
Step S119, and advances to Step S128.
[0177] When advanced to Step S128, the DSP/CPU 19 sends a control
signal to the motor driver circuit 3 to move the focus lens 2a to
the pan focus position acquired.
[0178] Next, at Step S129, the DSP/CPU 19 executes the still image
shooting processing under the photographic conditions locked at
Step S111, and records the still image data compressed by the JPEG
circuit 18 in the flash memory 24.
[0179] On the contrary, when judged at Step S117 that the AF
processing has been completed before the full depression of the
shutter button at Step S118, the DSP/CPU 19 advances to Step S130
in FIG. 10. At Step S130, the DSP/CPU 19 judges whether the AF
processing has failed.
[0180] When judged at Step S130 that the AF processing has failed,
the DSP/CPU 19 advances to Step S131, where the DSP/CPU 19 acquires
the zoom magnification for the present optical zoom.
[0181] Subsequently, the DSP/CPU 19 judges at Step S132 whether a
face has been detected immediately before the half depression of
the shutter button.
[0182] When judged at Step S132 that a face has been detected, the
DSP/CPU 19 advances to Step S133, where the DSP/CPU 19 determines
the type of the priority pan focus as the person-priority pan
focus. As a result of this, the DSP/CPU 19 acquires the focus
position for the pan focus, using the focus position table shown in
FIG. 2A.
[0183] Next, when determined that the type of the priority pan
focus is the person-priority pan focus, the DSP/CPU 19 advances to
Step S134. At Step S134, the DSP/CPU 19 acquires the focus position
for prioritizing a person from the focus position table shown in
FIG. 2A based on the zoom magnification acquired at Step S131, and
advances to Step S137.
[0184] On the other hand, when judged at Step S132 that a face has
not been detected, the DSP/CPU 19 advances to Step S135. At Step
S135, the DSP/CPU 19 executes the determination processing of the
type of the priority pan focus based on the photography scene. As
explained in the above-described first embodiment, the
determination processing performs the operation as shown in the
flowchart of FIG. 4.
[0185] Next, after determining the type of the priority pan focus
based on the photography scene, the DSP/CPU 19 advances to Step
S136. At Step S136, the DSP/CPU 19 acquires the focus position for
the pan focus from the focus position table shown in FIG. 2B based
on the type of the priority pan focus determined by the
determination processing and the zoom magnification acquired at
Step S131, and advances to Step S137.
[0186] When advanced to Step S137, the DSP/CPU 19 sends a control
signal to the motor driver circuit 3 to move the focus lens 2a to
the pan focus position acquired, and advances to Step S138.
[0187] In the mean time, when judged at Step S130 that the AF
processing has not failed, the DSP/CPU 19 advances to Step S138
without executing any further processing.
[0188] When advanced to Step S138, the DSP/CPU 19 judges whether
the shutter button has been fully depressed by the user.
[0189] When judged at Step S138 that the shutter button has not
been fully depressed, the DSP/CPU 19 remains at Step S138 until the
shutter button is fully depressed. Then, when judged that the
shutter button has been fully depressed, the DSP/CPU 19 advances to
Step S139. At Step S139, the DSP/CPU 19 executes the still image
shooting processing under the photographic conditions locked at
Step S111, and records the still image data compressed by the JPEG
circuit 18 in the flash memory 24.
[0190] As described so far above, in the second embodiment, when
the user is requesting the quick shooting, for example, when a face
has been detected in the case where the shutter button has been
fully depressed without stopping, the DSP/CPU 19 determines that
the photographic subject the user truly desires to shoot is a
person, and executes the pan focus processing using the focus
position table for person-priority pan focus (that is, the focus
position table as shown in FIG. 2A). On the other hand, when a face
has not been detected, the DSP/CPU 19 judges that the true
photographic subject the photographer desires to shoot is a
photographic subject other than a person such as a landscape, and
executes the pan focus processing using the focus position table
for non-person priority pan focus (that is, the focus position
table as shown in FIG. 2B). Accordingly, it is possible to focus
appropriately and quickly corresponding to the photographic subject
to shoot. In addition, it is possible to substantially enhance the
possibility that the true photographic subject is focused in the
pan focus processing.
[0191] Furthermore, when a face has been detected in the case where
the quick shooting is not requested by the user, the DSP/CPU 19
executes the auto-focus processing on the face. On the other hand,
when a face has not been detected, the DSP/CPU 19 executes the
auto-focus processing on the center of the angle of field.
Accordingly, it is possible to focus on the photographic subject
the user truly desires to shoot with high accuracy.
[0192] Furthermore, even in the case, when the optical zoom
magnification is larger than a predetermined magnification, where
the shutter button has been fully depressed without stopping, the
depth of field is reduced. The photographic subject is likely to be
out of focus if the pan focus processing is executed in such cases.
Executing the auto-focus processing enables focusing on the
photographic subject the user truly desires to shoot with high
accuracy.
[0193] Furthermore, when the auto-focus processing has failed, the
focusing lens position is not detected. Executing the pan focus
processing based on whether or not a face has been detected and on
the photography scene enables appropriately focusing on the true
photographic subject the photographer desires to shoot.
D. Variation Example 1 of the Second Embodiment
[0194] The following variation example of the second embodiment as
described above is possible.
[0195] In the second embodiment described above, when determined
that the type of the priority pan focus is the person-priority pan
focus, the DSP/CPU 19 acquires the focus position corresponding
only to the zoom magnification from the focus position table for
person-priority pan focus. In the present variation example,
however, the focus position is changed based on the size of the
detected face or the like, as explained in the above-described
variation example of the first embodiment.
[0196] As explained in the above-described variation example of the
first embodiment, in place of the focus position table shown in
FIG. 2A, the photographic subject distance table as shown in FIG. 5
has been recorded in the present variation example.
[0197] The operation of the present variation example will
hereinafter be described with reference to the flowchart of FIG.
11.
[0198] When determined that the type of the priority pan focus is
the person-priority pan focus at Step S124 in FIG. 9 or at Step
S133 in FIG. 10, the DSP/CPU 19 advances to Step S151 in FIG. 11.
At Step S151, the DSP/CPU 19 judges whether multiple faces have
been detected immediately before the half depression of the shutter
button.
[0199] When judged at Step S151 that multiple faces have not been
detected, that is, when judged that a single face has been
detected, the DSP/CPU 19 advances to Step S152. At Step S152, the
DSP/CPU 19 acquires the photographic subject distance from the
photographic subject distance table based on the size of the face
detecting frame 31 displayed corresponding to the zone of the
detected face (the face size) and the zoom magnification acquired,
and advances to Step S154.
[0200] Note that the individual photographic subject distances are
set corresponding to the size of the face detecting frame 31 and
the zoom magnification in the photographic subject distance table.
In place of this, the photographic subject distances may be set
corresponding to the size of the face and the zoom magnification.
In addition, the photographic subject distance is set in this
embodiment. It should be understood that the focus position may be
set in place of this.
[0201] On the other hand, when judged at Step S151 that multiple
faces have been detected, the DSP/CPU 19 advances to Step S153. At
Step S153, the DSP/CPU 19 acquires the photographic subject
distance from the photographic subject distance table based on the
size of the face detecting frame 31 displayed corresponding to the
zone of the face (the face size) identified as the main
photographic subject immediately before the half depression of the
shutter button and the zoom magnification acquired, and advances to
Step S154.
[0202] When advanced to Step S154, the DSP/CPU 19 acquires the
focus position corresponding to the photographic subject distance
acquired using the photographic subject distance/focus position
conversion table not shown, and after moving the focus lens 2a to
the focus position acquired, advances to Step S129 in FIG. 9 and
Step S138 in FIG. 10.
[0203] As described above, the photographic subject distance (the
focus position) is acquired based on the size of the detected face
and the zoom magnification. Accordingly, it is possible to quickly
focus on a person with high accuracy. In addition, it is possible
to substantially enhance the possibility that the true photographic
subject is focused in the pan focus processing.
[0204] Furthermore, when multiple faces have been detected, the
DSP/CPU 19 identifies the face which serves as the main
photographic subject, and acquires the photographic subject
distance based on the size of the face identified as the main
photographic subject and the zoom magnification. Accordingly, it is
possible to quickly focus on a main photographic subject with high
accuracy. In addition, it is possible to substantially enhance the
possibility that the true photographic subject is focused in the
pan focus processing.
E. Variation Example 2 of the Second Embodiment
[0205] In the second embodiment as described above, the optical
zoom is used to execute the zoom processing. Instead, both the
optical zoom and the electrical zoom may be used to execute the
zoom processing. In this embodiment, the judgment at Step S120 in
FIG. 9 is made based on whether the zoom magnification in the
optical zoom is larger than a predetermined magnification.
[0206] Furthermore, in place of the optical zoom, the electronic
zoom, in place of the optical zoom, may be used to execute the zoom
processing. In this case, when judged at Step S118 in FIG. 9 that
the shutter button has been fully depressed, the DSP/CPU 19
completes the AF processing according to the contrast detection
method, and after acquiring the electronic zoom magnification at
Step S119, subsequently advances to Step S123 without executing any
further processing.
F. Variation Example 3 of the Second Embodiment
[0207] In the second embodiment, the DSP/CPU 19 should start the AF
processing when the shutter button is half depressed, (Step S114 to
Step S116 in FIG. 8). On the other hand, when the shutter button
has been fully depressed before the AF processing is completed
(branched into Y at Step S118), the DSP/CPU 19 judges that the
shutter button has been fully depressed without stopping, that is,
that the user is requesting the quick shooting. However, the
judgment on whether the shutter button has been fully depressed
without stopping may be made according to the following
operation.
[0208] First, the judgment on whether the first shutter button has
been fully depressed without stopping will be described with
reference to the flowchart shown in FIG. 12.
[0209] When the shutter button is half depressed at Step S110 in
FIG. 8, and AE, AWB or the like are locked at Step S111, the
DSP/CPU 19 advances to Step S201 in FIG. 12, where the DSP/CPU 19
starts the timer. In the mean time, the DSP/CPU 19, which includes
the clock circuit, also has a function as the timer.
[0210] Subsequently, the DSP/CPU 19 judges at Step S202 whether
time is out. This judgment is made based on whether the timer has
passed a predetermined period of time (for example, 0.05
second).
[0211] When judged at Step S202 that time is not out, that is, that
the timer has not passed a predetermined period of time, the
DSP/CPU 19 advances to Step S203. At Step S203, the DSP/CPU 19
judges whether the shutter button has been fully depressed by the
user.
[0212] When judged at Step S203 that the shutter button has not
been fully depressed, the DSP/CPU 19 returns to Step S202.
[0213] On the other hand, when judged at Step S203 that the shutter
button has been fully depressed before a predetermined period of
time has passed, the DSP/CPU 19 judges that the shutter button has
been fully depressed without stopping, and thus advances to Step
S204. At Step S204, the DSP/CPU 19 acquires the zoom magnification
for the present optical zoom.
[0214] Subsequently, the DSP/CPU 19 judges at Step S205 whether the
zoom magnification of the optical zoom is within a range from
1-fold to a predetermined magnification.
[0215] When judged at Step S205 that the zoom magnification of the
optical zoom is within a range from 1-fold to a predetermined
magnification, the DSP/CPU 19 advances to Step S123 in FIG. 9. As a
result of this, the pan focus processing is executed corresponding
to whether or not a face has been detected.
[0216] On the other hand, when judged at Step S202 that time is out
before the shutter button is fully depressed, the DSP/CPU 19 judges
that the shutter button has been half depressed rather than fully
depressed without stopping, and advances to Step S206. In addition,
the DSP/CPU 19 advances to Step S206 also when judged at Step S205
that the zoom magnification of the optical zoom is not within a
range from 1-fold to a predetermined magnification. The reason for
this is the same as that explained in the second embodiment as
described above.
[0217] When advanced to Step S206, the DSP/CPU 19 judges whether a
face has been detected immediately before the half depression of
the shutter button.
[0218] When judged at Step S206 that a face has been detected, the
DSP/CPU 19 advances to Step S207. At Step S207, the DSP/CPU 19
judges whether multiple faces have been detected.
[0219] When judged at Step S207 that multiple faces have been
detected, the DSP/CPU 19 advances to Step S208. At Step S208, the
DSP/CPU 19 sets the AF area at the position of the face identified
as the main photographic subject immediately before the half
depression of the shutter button, and after staring the AF
processing according to the contrast detection method based on the
image data of the AF area it has set, advances to Step S211.
[0220] On the other hand, when judged that multiple faces have not
been detected at Step S207, that is, when judged that a single face
has been detected, the DSP/CPU 19 advances to Step S209. At Step
S209, the DSP/CPU 19 sets the AF area at the position of the
detected face, and after staring the AF processing according to the
contrast detection method based on the image data of the AF area it
has set, advances to Step S211.
[0221] On the contrary, when judged at Step S206 that a face has
been detected, the DSP/CPU 19 advances to Step S210. At Step S210,
the DSP/CPU 19 sets the AF area at the center of the field angle,
and after staring the AF processing according to the contrast
detection method based on the image data of the AF area it has set,
advances to Step S211.
[0222] When advanced to Step S211, the DSP/CPU 19 judges whether
the AF processing has been completed.
[0223] When judged at Step S211 that the AF processing has not been
completed, the DSP/CPU 19 remains at Step S211 until judged that AF
processing has been completed. Then, when judged that the AF
processing has been completed, the DSP/CPU 19 advances to Step
S212. At Step S212, the DSP/CPU 19 judges at Step S202 whether the
AF processing has been executed after time out.
[0224] When judged at Step S211 that the AF processing has been
executed after time out, the DSP/CPU 19 advances to Step S130 in
FIG. 10.
[0225] On the other hand, when judged at Step S211 that the AF
processing has been executed after time out, in other words, that
the DSP/CPU 19 has executed the AF processing at Step S205 after
judging that the zoom magnification is not within a range from
1-fold to a predetermined magnification, the DSP/CPU 19 advances to
Step S122 in FIG. 9.
[0226] Next, the judgment on whether the second shutter button has
been fully depressed without stopping will be described with
reference to the flowchart shown in FIG. 13.
[0227] The operations in the flowchart of FIG. 13 refers to the
operations for judging whether the shutter button has been fully
depressed without stopping, in the case where it is set such that
an operational signal corresponding to a half depression of the
shutter button is not detected unless the half-depression state of
the shutter button is maintained for at least a predetermined
period of time.
[0228] The flowchart of FIG. 13 is created by partially modifying
the flowchart of FIG. 12, and it will be explained referring to the
operations shown in the flowchart of FIG. 12.
[0229] When the face of the main photographic subject identified at
Step S109 in FIG. 8 is distinctly displayed, or when judged at Step
S107 that multiple faces have not been detected, the DSP/CPU 19
advances to Step S251 in FIG. 13. At Step S251, the DSP/CPU 19
judges whether the shutter button has been half depressed by the
user.
[0230] When judged at Step S251 that the shutter button has not
been half depressed, the DSP/CPU 19 advances to Step S252. At Step
S252, the DSP/CPU 19 judges whether the shutter button has been
fully depressed by the user.
[0231] When judged at Step S252 that the shutter button has not
been fully depressed, the DSP/CPU 19 returns to Step S105 in FIG.
8.
[0232] On the other hand, at Step S252, when judged that the
shutter button has been, not half depressed, but fully depressed,
the DSP/CPU 19 advances to Step S253. At Step S253, the DSP/CPU 19
locks the photographic conditions such as the exposure value, the
white balance value, and strobe flash ON/OFF, and advances to Step
S204 in FIG. 12.
[0233] On the other hand, when judged at Step S251 that the shutter
button has been half depressed, the DSP/CPU 19 judges that the
shutter button has been, not fully depressed without stopping, but
half depressed, and advances to Step S254. At Step S254, the
DSP/CPU 19 locks the photographic conditions such as the exposure
value, the white balance value, and the strobe flash ON/OFF, and
advances to Step S206 in FIG. 12.
[0234] At this time, the judgment at Step S212 in FIG. 12 is made
on whether the AF processing is executed after the shutter button
is half depressed. When judged at Step S211 that the AF processing
is executed after the half depression of the shutter button, the
DSP/CPU 19 advances to Step S130 in FIG. 10. On the other hand,
when judged that the AF processing is executed after the full
depression of the shutter button, the DSP/CPU 19 advances to Step
S122 in FIG. 9.
[0235] In this embodiment, the shutter button is a button having a
2-stage stroke enabling the half-depression operation and the
full-depression operation. However, the button may be a button
enabling the operation of only one stage. (a button that does not
have a 2-stage stroke, that is, a button that enables depression
only). In this case, a touch sensor for detecting if a finger
touches the touch sensor is provided at the upper section of the
shutter button. The DSP/CPU 19 judges that the shutter button has
been half depressed when a finger touches the touch sensor, and
judges that the shutter button has been fully depressed when the
shutter button is pressed down.
G. Variation Example 4 of the Second Embodiment
[0236] In the second embodiment as described above, in the case
where the shutter button has been fully depressed without stopping,
when a face has been detected, the DSP/CPU 19 determines that the
type of the priority pan focus is the person-priority pan focus and
execute the pan focus processing (at Steps S124, S125, S128 in FIG.
9, or Step S151 to Step S154 in FIG. 11). On the other hand, when
judged that a face has not been detected, the DSP/CPU 19 determines
that the type of the priority pan focus is the non-person priority
pan focus, and executes the pan focus processing (Steps S126, S127,
S128 in FIG. 9). However, when a face has not been detected, the
auto-focus processing may be executed, or no focus processing may
or need be executed. In this case, it is possible to provide a
person shooting mode, and to execute the focus processing when the
person shooting mode has been set.
[0237] In this case also, when the shutter button has been fully
depressed without stopping, it is possible to quickly and
appropriately execute the pan focus processing on the person who
serves as the true photographic subject. In addition, it is
possible to substantially enhance the possibility that the
photographic subject is focused.
H. Variation Examples of Individual Embodiments as Described
Above
[0238] The following variation examples are also possible for the
individual embodiments as described above.
[0239] (H1) The focus positions and the photographic subject
distances are set corresponding to the zoom magnification in the
focus position tables shown in FIG. 2A and FIG. 2B and in the
photographic subject distance table shown in FIG. 5. However, it is
also possible that the focus position and the photographic subject
distance are set corresponding only to the reference magnification
(for example, Zoom 1), and the focus position and the photographic
subject distance that have been set are modified in accordance with
the present zoom magnification.
[0240] Furthermore, it is also possible that the focus positions
and the photographic subject distances are calculated using the
calculating formula, instead of using the focus position table and
the photographic subject distance table.
[0241] Furthermore, the zoom magnification need not be verified for
the focus position.
[0242] (H2) In addition, in the individual embodiments of the
present invention as described above, it is also possible that the
pan focus processing is executed only when the zoom magnification
of the optical zoom is within a range from 1-fold to a
predetermined magnification, and the auto-focus processing is
executed when the zoom magnification of the optical zoom is larger
than a predetermined magnification.
[0243] In this case, it is possible that the focus processing is
executed corresponding to the zoom magnification of the optical
zoom, regardless of whether the shutter button has been fully
depressed without stopping. In addition, in the embodiments,
multiple types of the priority pan focus (the person-priority pan
focus, the short-distance priority pan focus, the long-distance
priority pan focus with full aperture, and the long-distance
priority pan focus without full aperture) are provided and the pan
focus processing is executed corresponding to the determined type
of the priority pan focus. However, it is also possible that only
one type of the priority pan focus is provided. That is, there is
no need for separating the pan focus processing into multiple
types.
[0244] In a conventional art, the pan focus processing is executed
in all cases regardless of the zoom magnification of the optical
zoom. However, if the pan focus processing is executed even in the
case where the zoom magnification of the optical zoom is larger
than a predetermined magnification, the photographic subject is
likely to be out of focus and therefore appropriate pan focus
processing cannot be executed.
[0245] Executing the pan focus processing only in the case where
the zoom magnification of the optical zoom is within a range from
1-fold to a predetermined magnification enables focusing on the
true photographic subject quickly and appropriately. In addition,
in the case where the zoom magnification of the optical zoom is
larger than a predetermined magnification, executing the auto-focus
processing enables appropriately focusing on the true photographic
subject although it takes some time for focusing.
[0246] (H3) Furthermore, in the individual embodiments of the
present invention as described, multiple types of the non-person
priority pan focus are provided (the short-distance priority pan
focus, the long-distance priority pan focus with full aperture and
the long-distance priority pan focus without full aperture).
However, it is also possible to provide only one type.
[0247] (H4) The individual embodiments of the present invention as
described above are merely examples as a best mode for carrying out
the invention, and aims to facilitate understanding of the
principle and the structure of the present invention. It is not
intended to limit the scope of the accompanying claims.
[0248] Therefore, it should be construed that various variations
and modifications for the above-described embodiments of the
present invention be included in the scope of the present invention
and protected by the scope of the accompanying claim of the present
invention.
[0249] Lastly, in the individual embodiments as described above, a
case where an imaging apparatus of the present invention is applied
to the digital camera 1 is described. However, the present
invention is not limited to the above-described embodiments. In
other words, the present invention may be applied to and any
apparatus as long as it can focus on the photographic subject.
[0250] Furthermore, although the processing program of the imaging
apparatus which is a preferred embodiment of the present invention
is stored in the memory (for example, ROM, etc.) of the imaging
apparatus, this processing program is stored thereon a
computer-readable medium and should also be protected in the case
of manufacturing, selling, etc. of only the program. In that case,
the method of protecting the program with a patent will be realized
by the form of the computer-readable medium on which the processing
program is stored.
[0251] While the present invention has been described with
reference to the preferred embodiments, it is intended that the
invention be not limited by any of the details of the description
therein but includes all the embodiments which fall within the
scope of the appended claims.
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