U.S. patent application number 10/344125 was filed with the patent office on 2003-08-28 for electronic camera.
Invention is credited to Kuroiwa, Toshihisa.
Application Number | 20030160874 10/344125 |
Document ID | / |
Family ID | 18732301 |
Filed Date | 2003-08-28 |
United States Patent
Application |
20030160874 |
Kind Code |
A1 |
Kuroiwa, Toshihisa |
August 28, 2003 |
Electronic camera
Abstract
An electronic camera of the present invention includes an image
pickup part performing "still image pickup generating a still image
signal" and "control image pickup successively generating control
image signals having higher frame rate" in time division; a still
image processing part applying predetermined still image signal
processing to the still image signal; a control image processing
part applying predetermined control signal processing to the
control image signals to extract control data; and a control part
performing at least one control operation out of exposure control,
focus control, and white balance control, based on the control data
output from the control image processing part. Particularly, in the
present invention, the control image processing part and the still
image processing part are configured to operate independently. The
control image processing part performs the signal processing on the
control image signals successively generated, even when the still
image signal is being signal-processed.
Inventors: |
Kuroiwa, Toshihisa;
(Miura-shi, JP) |
Correspondence
Address: |
Oliff & Berridge
PO Box 19928
Alexandria
VA
22320
US
|
Family ID: |
18732301 |
Appl. No.: |
10/344125 |
Filed: |
February 7, 2003 |
PCT Filed: |
July 19, 2001 |
PCT NO: |
PCT/JP01/06297 |
Current U.S.
Class: |
348/220.1 ;
348/222.1; 348/333.02; 348/333.05; 348/333.11; 348/E5.034;
348/E5.047; 348/E5.091 |
Current CPC
Class: |
H04N 5/335 20130101;
H04N 2101/00 20130101; H04N 5/235 20130101; H04N 5/23293
20130101 |
Class at
Publication: |
348/220.1 ;
348/222.1; 348/333.11; 348/333.05; 348/333.02 |
International
Class: |
H04N 005/225; H04N
005/222 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 9, 2000 |
JP |
2000-241038 |
Claims
1. An electronic camera comprising: an image pickup part for
performing "still image pickup for shooting a subject image to
generate a still image signal", and "control image pickup for
successively generating control image signals having a frame rate
higher than that of said still image signal" in time division; a
still image processing part for accepting said still image signal
generated by said image pickup part and applying predetermined
still image signal processing thereto; a control image processing
part for accepting said control image signals generated by said
image pickup part and applying predetermined control signal
processing thereto to extract control data; and a control part for
accepting said control data output from said control image
processing part and performing at least one control operation out
of exposure control, focus control, and white balance control,
based on said control data, wherein said control image processing
part and said still image processing part are configured to operate
independently, and said control image processing part performs the
signal processing on said control image signals successively
generated, even when said still image signal is being
signal-processed.
2. An electronic camera comprising: an image pickup part for
performing "still image pickup for shooting a subject image to
generate a still image signal" and "monitor-image pickup for
successively generating monitor-image signals having a frame rate
higher than that of said still image signal" in time division; a
still image processing part for accepting said still image signal
generated by said image pickup part and applying predetermined
still image signal processing thereto; and a monitor-image
processing part for accepting said monitor-image signals generated
by said image pickup part and applying predetermined monitor signal
processing thereto, wherein said monitor-image processing part and
said still image processing part are configured to operate
independently, and said monitor-image processing part performs the
signal processing on said monitor-image signals successively
generated, even when said still image signal is being
signal-processed.
3. The electronic camera according to claim 2, comprising a display
part for displaying said still image signal and said monitor-image
signals in one of a juxtaposed fashion, a nested fashion, and a
selective fashion.
4. The electronic camera according to claim 3, wherein said display
part has a first memory region for storing said still image signal
for monitor display use and a second memory region for storing said
monitor-image signals, said first and second memory regions being
independent from each other, and switches the memory region to be
displayed on a monitor to replace display on the monitor.
5. The electronic camera according to claim 2, comprising a control
image processing part for accepting said monitor-image signals
generated by said image pickup part and applying predetermined
control signal processing thereto to extract control data; and a
control part for accepting said control data output from said
control image processing part and performing at least one control
operation out of exposure control, focus control, and white balance
control, based on said control data, wherein said control image
processing part and said still image processing part are configured
to operate independently, and said control image processing part
performs the signal processing on said control image signals
successively generated, even when said still image signal is being
signal-processed.
6. An electronic camera comprising: an image pickup part for
performing "still image pickup for shooting a subject image to
generate a still image signal" and "monitor-image pickup for
successively generating monitor-image signals having a frame rate
higher than that of said still image signal" in time division; an
image processing part for applying predetermined still image signal
processing to said still image signal generated by said image
pickup part and for applying predetermined monitor signal
processing to said monitor-image signals generated by said image
pickup part; a control image processing part for accepting said
monitor-image signals generated by said image pickup part and
applying predetermined control signal processing thereto to extract
control data; and a control part for accepting said control data
output from said control image processing part and performing at
least one control operation out of exposure control, focus control,
and white balance control, based on said control data, wherein said
control image processing part and said image processing part are
configured to operate independently, and said control image
processing part performs the signal processing on said control
image signals successively generated, even when said still image
signal is being signal-processed.
7. The electronic camera according to claim 6, comprising a display
part for displaying said still image signal and said monitor-image
signals in one of a juxtaposed fashion, a nested fashion, and a
selective fashion.
8. The electronic camera according to claim 7, wherein said display
part has a first memory region for storing said still image signal
for monitor display use and a second memory region for storing said
monitor-image signals, said first and second memory regions being
independent from each other, and switches the memory region to be
displayed on a monitor to replace display on the monitor.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to an electronic camera which
performs still image pickup and monitor image pickup (or control
image pickup) of high frame rate in time division.
DESCRIPTION OF THE BACKGROUND ART
[0002] Conventionally, there have been known electronic cameras
that pick up monitor images at high frame rate and, in response to
a release operation by a photographer, perform still image pickup
at high resolution.
[0003] By the way, electronic cameras of this kind typically
perform signal processing on a still image (such as tone
conversion, color interpolation, and image compression) with
priority, immediately after a still image is picked up.
[0004] When still image processing is thus performed by priority,
the time before checking the monitor of the still image signal can
be reduced as much as possible. In addition, image compression is
started quickly to ease the memory size of the image data, so that
there is an advantageous effect that there can be increase in the
number of possible exposures when continuously shooting.
[0005] While performing such still image processing, however, it
was a necessity to stop picking up the monitor image or stop
processing the monitor signal. Because of that, there have been
problems of the monitor display being interrupted, or control
operations of electronic cameras that use monitor images (such as
focus control) being interrupted.
[0006] Such interruptions have caused a time lag such that the
focus control of the electronic camera is exercised again,
producing the adverse effect of delaying the next monitor display
and still image pickup. Recently in particular, the foregoing
adverse effect has had a propensity to grow in influence because
the processing time of still images is on the increase due to
electronic cameras having higher resolutions.
DISCLOSURE OF THE INVENTION
[0007] In view of the foregoing problem, it is thus an object of
the present invention to provide an electronic camera which
performs signal processing on image signals of high frame rate
picked up in succession, even when a still image is being
signal-processed.
[0008] Hereinafter, the contents of claims of the present invention
will be described item by item.
[0009] (1) An electronic camera of the present invention comprises
an image pickup part, a still image processing part, a control
image processing part, and a control part.
[0010] This image pickup part performs "still image pickup for
shooting a subject image to generate a still image signal" and
"control image pickup for successively generating control image
signals having a frame rate higher than that of the still image
signal" in time division.
[0011] Moreover, the still image processing part accepts the still
image signal generated by the image pickup part and applies
predetermined still image signal processing to this still image
signal.
[0012] Furthermore, the control image processing part accepts the
control image signals generated by the image pickup part and
applies predetermined control signal processing to these control
image signals to extract control data.
[0013] Besides, the control part accepts the control data output
from the control image processing part and performs at least one
control operation out of exposure control, focus control, and white
balance control, based on this control data.
[0014] In particular, the present invention is characterized in
that the control image processing part and the still image
processing part mentioned above are configured to operate
independently, and the control image processing part performs the
signal processing on the control image signals successively
generated, even when the still image signal is being
signal-processed.
[0015] In such a configuration, the control image processing part
can process the control image signals picked up in succession by
the image pickup part so that the control data is extracted
smoothly even when the still image signal is being processed.
[0016] As a result, the continuous extracting of the control data
will not be needlessly interrupted, even in the course of
processing the still image signal. Therefore, it becomes possible
to obtain control data as continuously as possible, and the adverse
effect, that control operations may be delayed because they follow
discontinuous change in the control data, can be mended.
[0017] (2) Moreover, another electronic camera of the present
invention comprises an image pickup part, a still image processing
part, and a monitor-image processing part.
[0018] This image pickup part performs "still image pickup for
shooting a subject image to generate a still image signal" and
"monitor-image pickup for successively generating monitor-image
signals having a frame rate higher than that of the still image
signal" in time division.
[0019] Besides, the still image processing part accepts the still
image signal generated by this image pickup part and applies
predetermined still image signal processing to this still image
signal.
[0020] Furthermore, the monitor-image processing part accepts the
monitor-image signals generated by the image pickup part and
applies predetermined monitor signal processing to these
monitor-image signals.
[0021] In particular, the present invention is characterized in
that the monitor-image processing part and the still image
processing part are configured to operate independently, and the
monitor-image processing part performs the signal processing on the
monitor-image signals successively generated, even when the still
image signal is being signal-processed.
[0022] In such a configuration, the monitor-image processing part
can smoothly process the monitor-image signals picked up in
succession by the image pickup part, even when the still image
signal is being processed.
[0023] As a result, monitor images are displayed without uselessly
being interrupted even in the course of processing the still image
signal. The monitor images can thus be displayed as continuously as
possible.
[0024] (3) Furthermore, another electronic camera of the present
invention is the electronic camera as set forth in the foregoing
section (2), comprising a control image processing part and a
control part.
[0025] This control image processing part accepts the monitor-image
signals generated by the image pickup part and applies
predetermined control signal processing to these monitor-image
signals to extract control data.
[0026] Besides, the control part accepts the control data output
from the control image processing part and performs at least one
control operation out of exposure control, focus control, and white
balance control, based on this control data.
[0027] In particular, the present invention is characterized in
that the control image processing part and the still image
processing part are configured to operate independently, and the
control image processing part performs the signal processing on the
monitor-image signals successively generated, even when the still
image signal is being signal-processed.
[0028] In such a configuration, "the extraction of the control
data" and "the monitor signal processing" will not be needlessly
interrupted, even in the course of processing the still image
signal. Therefore, the adverse effect that subsequent monitor
displays and control operations are delayed can be mended.
[0029] (4) Furthermore, another electronic camera of the present
invention comprises an image pickup part, an image processing part,
a control image processing part, and a control part.
[0030] This image pickup part performs "still image pickup for
shooting a subject image to generate a still image signal" and
"monitor-image pickup for successively generating monitor-image
signals having a frame rate higher than that of the still image
signal" in time division.
[0031] Moreover, the image processing part applies predetermined
still image signal processing to the still image signal generated
by the image pickup part and applies predetermined monitor signal
processing to the monitor-image signals generated by the image
pickup part.
[0032] Furthermore, the control image processing part applies
predetermined control signal processing to the monitor-image
signals generated by the image pickup part to extract control
data.
[0033] Besides, the control part performs at least one control
operation out of exposure control, focus control, and white balance
control, based on the control data output from the control image
processing part.
[0034] In particular, the present invention is characterized in
that the control image processing part and the image processing
part are configured to operate independently, and the control image
processing part performs the signal processing on the control image
signals successively generated, even when the still image signal is
being signal-processed.
[0035] In such a configuration, the signal processing of the still
image signal and the monitor-image signals is performed by the
image processing part, which is a single unit. Therefore, it
becomes possible to reduce the circuit scale of the apparatus as
compared to the case where the still image processing part and the
monitor-image processing part are provided independently. As a
result, power consumption can easily be reduced, resulting in
extending the battery life of the electronic camera.
[0036] Incidentally, in the foregoing configuration, the signal
processing of the still image signal and that of the monitor-image
signal cannot be perfectly synchronized. On that account, when the
still image signal is processed with priority, updating the monitor
display while the still image signal is being signal-processed
becomes difficult. Nevertheless, even under these circumstances,
the control image processing part can extract the control data from
the monitor-image signals. Thus, although the monitor display
cannot be updated, the continuity of the control data will not be
needlessly interrupted and the control data can be obtained as
continuously as possible. Consequently, it becomes possible to mend
the adverse effect that control operations may be delayed because
they follow discontinuous change in control data.
[0037] (5) Another electronic camera of the present invention is
the electronic camera as set forth in the foregoing section (2) or
the foregoing section (4), comprising a display part for displaying
the still image signal and the monitor-image signals in a
juxtaposed fashion, in a nested fashion, or in a selective
fashion.
[0038] When images are displayed in a juxtaposed fashion, it
becomes possible to determine the next composition based on the
moving image display by the monitor-image signals and to check the
monitor by the still image signal at the same time.
[0039] Moreover, when images are displayed in a nested fashion, the
images displayed concurrently are more in a subordinate-superior
relationship than in when they are displayed in a juxtaposed
fashion. It is thus easier to recognize intuitively which image is
which.
[0040] Furthermore, when images are displayed selectively, it
becomes possible to check the desired image signal alone on the
monitor.
[0041] (6) Another electronic camera of the present invention is
the electronic camera as set forth in the foregoing section (5),
wherein the display part has a first memory region for storing the
still image signal for monitor display use and a second memory
region for storing the monitor-image signals, the first and second
memory regions being independent from each other, and switches the
memory region to be displayed on a monitor to replace display on
the monitor.
[0042] In such a configuration, the two memory regions are
independent from each other. This makes it possible to replace the
display on the monitor quickly by switching the memory region to be
displayed on the monitor. This allows such operations as
instantaneously replacing the positions of images to be displayed
in a juxtaposed fashion and instantaneously switching a still image
display with a monitor image.
[0043] Incidentally, the foregoing object and other objects of the
present invention can be seen easily from the following description
and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] FIG. 1 is a diagram showing the configuration of an
electronic camera 11 according to the first embodiment;
[0045] FIG. 2 is a timing chart for explaining the operation of the
electronic camera 11;
[0046] FIG. 3 is a flowchart for explaining the operation of a
video output circuit 32;
[0047] FIG. 4 is a diagram showing display examples of a display
screen 33; and
[0048] FIG. 5 is a diagram showing the configuration of an
electronic camera 11a according to the second embodiment.
BEST MODE FOR CARRYING OUT THE INVENTION
[0049] Hereinafter, embodiments of the present invention will be
described with reference to the drawings.
[0050] <<First Embodiment>>
[0051] A first embodiment is one corresponding to the inventions of
claims 1-5.
[0052] (Configuration of First Embodiment)
[0053] FIG. 1 is a diagram showing the configuration of an
electronic camera 11.
[0054] FIG. 2 is a timing chart for explaining the operation of the
electronic camera 11.
[0055] In FIG. 1, a shooting lens 12 is mounted on the electronic
camera 11. The image pickup surface of an image pickup device 13 is
situated on the optical axis of this shooting lens 12 via a
diaphragm 12a. Incidentally, for the sake of avoiding smear in
reading a still image signal after release, a mechanical shutter
may be arranged in front of the image pickup surface of the image
pickup device 13.
[0056] An image signal output from this image pickup device 13 is
supplied to a still image processing part 15 and a moving image
processing part 25 through an A/D conversion part 14.
[0057] This still image processing part 15 is composed of an image
processing part 16 for performing a 2D image process, a thumbnail
creating part 17 for creating thumbnails, a JPEG compression part
18 for performing JPEG compression, and a size conversion part 18
for converting image sizes for use in monitor display of still
images. These processing parts 16-19 are connected to a second bus
20 which is used chiefly for image processing, through FIFO
(First-In First-Out memories) 21-24, respectively.
[0058] Here, the image processing part 16 performs imperfect pixel
correction, black level clamp, gain adjustment, white balance
adjustment, tone conversion, color interpolation, color coordinate
conversion, filtering, etc. Of these, a series of processes capable
of real-time processing such as imperfect pixel correction, black
level clamp, and gain adjustment is processed in real time as a
first step. Here, white balance adjustment is executed as part of
the real-time processing if white balance adjustment values are
obtained in advance from monitor-image signals or the like. Tone
conversion can also be executed as part of the real-time processing
if it can be processed before color interpolation.
[0059] On the other hand, color interpolation and filtering are
difficult to execute as part of the real-time processing since they
are 2D image processes. Then, these 2D image processes are executed
as a second step while data is exchanged with an image memory 41 to
be described later.
[0060] Meanwhile, the moving image processing part 25 is composed
of a monitor-image processing part 26 for performing signal
processing on a monitor-image signal and a control image processing
part 27 for extracting control data from predetermined regions of a
monitor image. The output of this monitor-image processing part 26
is connected to the second bus 20 through a FIFO 28. Moreover, the
output of the control image processing part 27 is connected to a
first bus 29 which is used chiefly for system control.
[0061] The image memory 41 is also connected to the second bus 20.
A monitor-display memory region 30 in the image memory 41 is
provided with two memory regions (viewfinder region 30a, quickview
region 30b) which are capable of independent accesses.
Incidentally, this image memory 41 is also used as a work memory in
performing signal processing.
[0062] Moreover, the second bus 20 is connected with a video output
circuit 32 through a FIFO 31. This video output circuit 32 drives a
display screen 33 to exercise image display.
[0063] Now, the first bus 29 is connected with a microprocessor 34
for performing system control, a RAM 35, a ROM 36, and so on. This
microprocessor 34 is connected with the still image processing part
15, the monitor-image processing part 26, the control image
processing part 27, the video output circuit 32, a focus control
part 38 for performing a focus control on the shooting lens 12, a
diaphragm control part 39 for controlling the diaphragm 12a, a
timing generator 40 for controlling the image pickup device 13 and
the A/D conversion part 14, and so on, in order that control
signals for system control are transmitted thereto,
respectively.
[0064] Incidentally, these control signals may be transmitted to
the respective units through the first bus 29. Incidentally, when a
mechanical shutter is provided, a control signal of the
microprocessor 34 is also transmitted to a control unit of the
mechanical shutter.
[0065] (Correspondence Between the Foregoing Configuration and the
Present Invention)
[0066] Hereinafter, description will be given of the correspondence
between the first embodiment and the present invention.
[0067] The image pickup part as set forth in claims corresponds to
the image pickup device 13 and the timing generator 40.
[0068] The still image processing part as set forth in claims
corresponds to the still image processing part 15.
[0069] The control image processing part as set forth in claims
corresponds to the control image processing part 27.
[0070] The control part as set forth in claims corresponds to the
microprocessor 34, the focus control part 38, the diaphragm control
part 39, the timing generator 40, the monitor-image processing part
26 (a white balance adjustment function thereof), etc.
[0071] The control image signal as set forth in claims corresponds
to the monitor-image signal.
[0072] The monitor-image processing part as set forth in claims
corresponds to the monitor-image processing part 26.
[0073] The display part as set forth in claims corresponds to the
monitor-display memory region 30 for and the video output circuit
32.
[0074] The first memory region as set forth in claims corresponds
to the quickview region 30b.
[0075] The second memory region as set forth in claims corresponds
to the viewfinder region 30a.
[0076] Next, characteristic operations of the first embodiment will
be described individually.
[0077] (Monitor-Image Signals Processing Operation)
[0078] Initially, description will be given of the operation for
processing monitor-image signals.
[0079] The timing generator 40 drives the image pickup device 13 to
generate monitor-image signals in succession. These monitor-image
signals are image signals of high frame rate, being generated by
partially reading data that is generated pixel by pixel in the
image pickup device 13. Incidentally, when the image pickup device
13 is a CCD, the monitor-image signals are often signals whose
lines are partially skipped being read.
[0080] The monitor-image signals thus successively generated are
digitized by the A/D conversion part 14 before supplied to both the
monitor-image processing part 26 and the control image processing
part 27.
[0081] The monitor-image processing part 26 performs signal
processing for monitor display (such as color interpolation and
tone conversion) on the monitor-image signals. Concurrently with
this signal processing, the monitor-image processing part 26
transfers and records the processed monitor-image signals onto the
viewfinder region 30a in the monitor-display memory region 30
arranged in the image memory 41 through the second bus 20. The
video output circuit 32 reads the monitor-image signals from this
viewfinder region 30a periodically, and displays the monitor-image
signals on the display screen 33 as moving images.
[0082] Meanwhile, the control image processing part 27 extracts a
regional image of a focus detection area, a regional image of a
photometric area, and a regional image of a white balance area
individually from the monitor-image signals. Incidentally, these
areas can be changed freely by a control signal from the
microprocessor 34. Moreover, unless there is a specific problem,
these areas may be united to omit redundancy in the processing for
extracting the regional images.
[0083] The control image processing part 27 performs operations on
these regional images to extract control data (here, a contrast
value, a photometric value, and a white balance value).
[0084] Concurrently with this extracting operation, the control
image processing part 27 successively outputs the extracted control
data to the microprocessor 34 through the first bus 29.
[0085] Here, the microprocessor 34 performs operations based on the
control data of the contrast value to drive the focus control part
38, thereby exercising a focus control of contrast hill-climbing
method.
[0086] The microprocessor 34 also performs an exposure operation
based on the control data of the photometric value, thereby
exercising an exposure control through the diaphragm control part
39 and the timing generator 40 (electronic shutter). Incidentally,
at the time of the control image pickup (monitor-image pickup), the
depth of focus of the shooting lens 12 is better rendered shallower
to increase the detection sensitivity to focus errors (peaks in
contrast value). Thus, the diaphragm 12a is preferably fixed to
near release.
[0087] Moreover, the microprocessor 34 transmits the control data
of the white balance adjustment value to the monitor-image
processing part (or still image processing part) for the sake of a
white balance adjustment.
[0088] The focus control and exposure control described above are
locked after the release is half pressed. During this control lock,
the shooting lens 12 is fixed to the focus position and the
exposure control value is held by the microprocessor 34 in
preparation for still image pickup by a full press of the release.
Incidentally, as shown in FIG. 2, the image pickup operation of the
monitor-image signals, the extraction processing of the control
data, the white balance adjustment, the operation for a focus
control, the operation for an exposure control, and the like
continue being performed even after the half press.
[0089] By the sequential processing of the monitor-image signals
described above, the control operation of the electronic camera 11
and the moving image display of the monitor-image signals continue
being effected as shown in FIG. 2.
[0090] (Still Image Signal Processing Operation)
[0091] Next, description will be given of the operation for
processing a still image signal.
[0092] When the release button of the electronic camera 11 is full
pressed during the operation for processing monitor-image signals
as described above, the microprocessor 34 controls the timing
generator 40 to perform still image pickup (exposure) based on the
exposure control value held at the time of the control lock
(control of the diaphragm 12a and the electronic shutter), and then
reads a still image signal from the image pickup device 13. This
still image signal is an image signal of high resolution, being
read from the image pickup device 13 with no partial reading.
[0093] The still image signal generated thus is digitized by the
A/D conversion part 14 before supplied to the image processing part
16. The image processing part 16 performs, as described above, the
real-time processing of the first step and the 2D image process of
the second step on this still image signal.
[0094] Here, if a white balance adjustment is to be made to the
still image signal by using the white balance adjustment value
obtained in the immediately preceding control image pickup
(monitor-image pickup), the microprocessor 34 sets this adjustment
value to the image processing part 16 before the read of the still
image signal so that the white balance adjustment is made in the
process of the real-time processing.
[0095] The image processing part 16, each time it completes the 2D
image process for a minimum unit of processing, supplies the still
image signal past the 2D image process (YCbCr, RGB, or such an
image signal) to the thumbnail creating part 17, the JPEG
compression part 18, and the size conversion part 19 as needed.
[0096] The thumbnail creating part 17 creates a thumbnail image
based on the still image signal supplied thus.
[0097] The JPEG compression part 18 performs JPEG test compression
and JPEG full compression based on the still image signal
(typically a YCbCr image signal) supplied thus, compressing the
still image signal to a target code volume.
[0098] Incidentally, the JPEG compression part 18 also performs
image compression of the thumbnail image during such JPEG
compression.
[0099] The compressed image data and thumbnail compressed data
processed thus are integrated into JPEG files and stored into a
memory card (not shown).
[0100] Meanwhile, the size conversion part 19 performs size
conversion for quickview (monitor check of the result of the image
pickup) based on the still image signal supplied thus. Concurrently
with such size conversion, the size conversion part 19 transfers
and records the size-converted still image signal onto the
quickview region 30b through the second bus 20. The video output
circuit 32 reads the still image signal from this quickview region
30b, and makes a quickview display on the display screen 33.
[0101] Incidentally, when the output signal of the video output
circuit 32 is a video signal of NTSC format, PAL format, or SECAM
format, the size conversion part 19 is supplied with a YCbCr image
signal.
[0102] By the processing of the still image signal described above,
the still image signal is stored and a quickview display is
effected as shown in FIG. 2.
[0103] (Concerning Processing of Monitor-Image Signals during
Signal Processing of Still Image Signal)
[0104] Next, description will be given of the processing of
monitor-image signals during the signal processing of a still image
signal described above.
[0105] Initially, as shown in FIG. 2, the timing generator 40
restarts the successive generation of monitor-image signals
immediately after the completion of read of the still image signal.
Here, the still image processing part 15 has started the signal
processing on the still image signal.
[0106] The control image processing part 27 restarts the operation
of extracting control data from monitor-image signals immediately
without hampering the operation of this still image processing part
15 at all.
[0107] In addition, the monitor-image processing part 26 restarts
the monitor signal processing immediately without hampering the
operation of this still image processing part 15 at all.
[0108] (Concerning Monitor Display Replacing Operation)
[0109] FIG. 3 is a flowchart for explaining the operation of the
video output circuit 32.
[0110] Hereinafter, the operation for replacing monitor display
will be described with reference to the step numbers shown in FIG.
3.
[0111] Step S1: Initially, the video output circuit 32 sets the
scanning position of the display screen 33 to an initial position
(such as the upper left of the screen).
[0112] Step S2: The video output circuit 32 determines which screen
to display mainly (hereinafter, referred to as "main screen") in
accordance with internal flag information. Here, when the
viewfinder is the main screen, the video output circuit 32 moves to
step S3 in operation. On the other hand, when the quickview is the
main screen, the video output circuit 32 moves to step S5 in
operation. Incidentally, the microprocessor 34 can rewrite the flag
information in this video output circuit 32 to change the screen to
display mainly as needed.
[0113] Step S3: Here, the viewfinder is selected as the main
screen. Then, the video output circuit 32 substitutes the top
address of the viewfinder region 30a, the main screen, for a memory
pointer P1.
[0114] Step S4: Moreover, the video output circuit 32 substitutes
the top address of the quickview region 30b for another memory
pointer P2. After the completion of such pointer setting, the video
output circuit 32 moves to step S7 in operation.
[0115] Step S5: Here, the quickview is selected as the main screen.
Then, the video output circuit 32 substitutes the top address of
the quickview region 30b, the main screen, for the memory pointer
P1.
[0116] Step S6: Moreover, the video output circuit 32 substitutes
the top address of the viewfinder region 30a for the other memory
pointer P2. After the completion of such pointer setting, the video
output circuit 32 moves to step S7 in operation.
[0117] Step S7: The video output circuit 32 selects the display
mode of the screen in accordance with internal flag information.
Here, when a full screen display is selected as the display mode,
the video output circuit 32 moves to step S8 in operation. On the
other hand, when a nested display is selected, the video output
circuit 32 moves to step S9 in operation. Incidentally, the
microprocessor 34 can rewrite the flag information in this video
output circuit 32 to change the display mode as needed.
[0118] Step S8: The video output circuit 32 reads an image signal
from the memory pointer P1 and sets the signal value in the
scanning position of the display screen 33. After such setting, the
video output circuit 32 moves to step S12 in operation.
[0119] Step S9: Since the nested display is selected here, the
video output circuit 32 determines whether or not the current
scanning position corresponds to the nested screen.
[0120] When the current scanning position does not correspond to
the nested screen, the video output circuit 32 moves to step S8 in
operation to perform the same operation as with full screen
display.
[0121] On the other hand, when the current scanning position
corresponds to the nested screen, the video output circuit 32 moves
to step S10 in operation to perform the processing of the nested
screen.
[0122] Step S10: To perform the processing of the nested screen
here, the video output circuit 32 partially reads an image signal
from the memory pointer P2, and sets the signal value in the
scanning position of the display screen 33.
[0123] Step S11: The video output circuit 32 increments the memory
pointer P2 by the partial amount not read, in preparation for the
next pointer reference.
[0124] Step S12: The video output circuit 32 increments the memory
pointer P1 and the scanning position in preparation for the next
pointer reference.
[0125] Step S13: Here, the video output circuit 32 determines
whether the scanning is completed or not. If the scanning is not
completed, the video output circuit 32 returns to step S7 in
operation to continue scanning the display screen 33. On the other
hand, if the scanning is completed, the video output circuit 32
returns to step S1 in operation to repeat the scanning of the
display screen 33 from the initial position.
[0126] (Effects, Etc. of the First Embodiment)
[0127] As described above, in the first embodiment, the generation
of a monitor-image signal is restarted immediately after the
generation of a still image signal as shown in FIG. 2. In response
to this monitor-image signal, the control image processing part 27
restarts the operation for extracting control data immediately.
Consequently, the control data has high continuity, which can
effectively preclude the problem that a discontinuous change in the
control data causes a delay in subsequent control operations.
[0128] Besides, in the first embodiment, the monitor-image
processing part 26 performs the processing of monitor-image signals
even while a still image signal is processed. It is therefore
possible to display the monitor-image signals even during the still
image signal processing.
[0129] Moreover, in the first embodiment, the operation of the
video output circuit 32 described above makes it possible to
display four types of screens shown in FIGS. 4(a)-(d) on the
display screen 33. In this case, the microprocessor 34 can rewrite
the flag information in the video output circuit 32 to switch these
four types of screens instantaneously.
[0130] In particular, the first embodiment comprises the second bus
20 for exchanging still image signals and the first bus 29 for
exchanging control data, the buses being independent of each other.
This precludes the still image signals and the control data from
conflicting on an identical bus, and makes it possible to perform
the still image processing and the control operations smoothly in
parallel.
[0131] Furthermore, in the first embodiment, the image pickup
operation of the monitor-image signals, the extraction processing
of the control data, the white balance adjustment to the monitor
images, the operation for a focus control, and the operation for an
exposure control are continued even after the release is half
pressed. The control data and the operations can thus be maintained
at high continuity even after the half press. Consequently, it
becomes possible to effectively preclude such adverse effects that
the control operations delay restarting after the half-pressed
state is cleared.
[0132] Now, description will be given of another embodiment.
[0133] <<Second Embodiment>>
[0134] A second embodiment is one corresponding to the inventions
of claims 1 and 6-8.
[0135] FIG. 5 is a diagram showing the configuration of an
electronic camera 11a according to the second embodiment.
[0136] The configuration of the second embodiment is characterized
in that the still image processing part 15, the monitor-image
processing part 26, and the FIFO 28 are omitted from the electronic
camera 11 described above (FIG. 1), and a general-purpose image
processing part 15a is arranged instead.
[0137] This general-purpose image processing part 15a contains an
image processing part 16a. This image processing part 16a performs
still image signal processing or signal processing for a monitor
image selectively depending on the type of the image signal (still
image signal, monitor-image signal) designated by the
microprocessor 34.
[0138] Incidentally, since the components and operations are
otherwise the same as in the first embodiment, description thereof
will be omitted here.
[0139] As above, according to the second embodiment, the signal
processing circuits dedicated to monitor-image signals become
unnecessary. This makes it possible to reduce the circuit scale of
the entire electronic camera. As a result, the power consumption of
the electronic camera can be lowered to extend the battery life of
the electronic camera.
[0140] Moreover, since the control image processing part 27
extracts control data even during the signal processing of still
image signals, the control data can be obtained as continuously as
possible. This can improve the problem that a discontinuous change
in the control data causes a delay in control operations.
[0141] Furthermore, in the second embodiment, the image processing
part 16a for performing image processing for general purpose use
and the JPEG compression part 18 and the like for performing signal
processing dedicated to still image signals are configured capable
of independent operations. The image processing part 16a can thus
enter the signal processing of monitor-image signals quickly after
the signal processing of a still image signal shifts to the JPEG
compression part 18 and the like. As a result, it becomes possible
to shorten the interruption of monitor display.
[0142] (Supplemental Remarks on Embodiments)
[0143] Incidentally, in the embodiments described above, regional
images are cut out of the monitor-image signals, and control data
(such as a contrast value, a photometric value, and a white balance
value) is calculated from these regional images. However, the
control data is not limited thereto. For example, the control image
processing part 27 may cut regional images out of the monitor-image
signals and transmit these regional images to the microprocessor 34
as the control data. In this case, the microprocessor 34 performs
operations for a contrast value, a photometric value, a white
balance value, etc. based on the regional images.
[0144] Moreover, in the foregoing embodiments, the control data is
not extracted from the still image signal. However, this is not
restrictive. For example, the control image processing part 27 may
extract control data from the still image signal (see dotted
portions shown in FIG. 2). In this case, the continuity of the
control data can be enhanced further, allowing an additional
improvement to the adverse effect that subsequent monitor display
and still image pickup might get delayed due to a discontinuous
change in the control data.
[0145] Incidentally, the foregoing embodiments have dealt with the
cases where the video output circuit 32 makes a full screen display
and a nested display. However, this is not restrictive. For
example, the video output circuit 32 may arrange two screens on the
display screen 33 for juxtaposed display.
[0146] Moreover, in the foregoing embodiments, the video output
circuit 32 switches the memory pointers P1 and P2 in accordance
with the scanning position of the screen. However, this is not
restrictive. For example, image signals may be read from the two
memory regions 30a and 30b in parallel (as concerns a nested
screen, partial read shall be performed) so that the video output
circuit 32 selects which image signal to display in accordance with
the scanning position.
[0147] By the way, in the present invention, the control data has
high continuity even during the signal processing of the still
image signal. This improves the continuity of the focus control and
the like. Consequently, the next release operation can be accepted
easily even during the signal processing of the still image signal.
In such a case, it is preferable to perform either of the following
operations:
[0148] 1) The still image processing part 15 continues the signal
processing of the still image signal (2D image process in
particular) and captures the released still image signal (at least
temporarily records the same on the image memory) concurrently.
Incidentally, the capture is preferably accompanied with the
real-time processing.
[0149] 2) The still image processing part 15 suspends the signal
processing of the still image signal, captures the released still
image signal (at least temporarily records the same on the image
memory) as an interrupt, and restarts the suspended signal
processing after the completion of the capture. Incidentally, the
capture is preferably accompanied with the real-time
processing.
[0150] These operations can reduce the possibility of missing the
right moment for a valuable shot.
[0151] The invention may be embodied in other specific forms
without departing from the spirit and essential characteristics
thereof. The foregoing embodiments are therefore to be considered
in all aspects as illustrative and not restrictive. The scope of
the invention is indicated by the appended claims rather than by
the foregoing description. All changes which come within the
meaning and range of equivalency of the claims are therefore
intended to be embraced therein.
* * * * *