U.S. patent application number 10/886240 was filed with the patent office on 2004-12-09 for imaging apparatus.
Invention is credited to Nakano, Masaki, Ogino, Hiroyuki, Okada, Masaki, Yamagata, Shigeo.
Application Number | 20040246359 10/886240 |
Document ID | / |
Family ID | 33494392 |
Filed Date | 2004-12-09 |
United States Patent
Application |
20040246359 |
Kind Code |
A1 |
Ogino, Hiroyuki ; et
al. |
December 9, 2004 |
Imaging apparatus
Abstract
Upon detection of the attachment of a recording medium, an image
signal obtained by taking a picture and condition information
representing a condition in which the picture is taken are read out
form a memory in an image pickup apparatus and recorded on the
recording medium. The apparatus is also arranged in such a manner
that the condition information recorded on the recording medium may
be transferred to the memory. With this arrangement, it becomes
possible to process the image signal by using the condition
information stored in the memory, even in a situation in which the
recording medium is detached. Furthermore, it becomes possible to
inherit the condition information even when the recording medium is
exchanged.
Inventors: |
Ogino, Hiroyuki;
(Kanagawa-ken, JP) ; Yamagata, Shigeo;
(Kanagawa-ken, JP) ; Nakano, Masaki;
(Kanagawa-ken, JP) ; Okada, Masaki; (Kanagawa-ken,
JP) |
Correspondence
Address: |
Robin, Blecker & Daley
330 Madison Avenue
New York
NY
10017
US
|
Family ID: |
33494392 |
Appl. No.: |
10/886240 |
Filed: |
July 7, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10886240 |
Jul 7, 2004 |
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08818245 |
Mar 14, 1997 |
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08818245 |
Mar 14, 1997 |
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08440328 |
May 12, 1995 |
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08440328 |
May 12, 1995 |
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08116329 |
Sep 3, 1993 |
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Current U.S.
Class: |
348/333.01 ;
348/E9.052; 386/E5.072 |
Current CPC
Class: |
H04N 9/8205 20130101;
H04N 9/735 20130101; H04N 5/772 20130101; H04N 5/781 20130101 |
Class at
Publication: |
348/333.01 |
International
Class: |
H04N 005/335 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 10, 1992 |
JP |
HEI 04-242077 |
Dec 21, 1992 |
JP |
HEI 04-356252 |
Dec 24, 1992 |
JP |
HEI 04-357632 |
Dec 24, 1992 |
JP |
HEI 04-357634 |
Claims
1. A conversion method characterized by displaying at least one
sensed image; setting a standard data based on the displayed sensed
image; storing the standard data set; and converting another sensed
image based on the standard data stored.
2. A conversion method of claim 1 characterized by that the sensed
image set as said standard data is an image photographing an object
of achromatic color.
3. A conversion method of claim 1 characterized by that the sensed
image set as said standard data is a part of an image photographing
an object of achromatic color.
4. A recording apparatus characterized by having a sensed image
input device for inputting a sensed image; an inputting device of a
standard image for color processing of said sensed image
which-inputs the standard image for color processing of said sensed
image; and a recording device which records an information
corresponding to the standard image for color processing of said
sensed image, connecting it with another sensed image.
5. A recording apparatus of claim 4 characterized by that the
standard image for color processing of said sensed image is an
image photographing an object of achromatic color.
6. A recording apparatus of claim 5 characterized by that the
information corresponding to the standard image for color
processing of said sensed image is a control value of white balance
obtained from the image photographing said object of achromatic
color.
7. A recording apparatus of claim 5 characterized by that the
information corresponding to the standard image for color
processing of said sensed image is a part of the image
photographing said object of achromatic color.
8. A recording apparatus of claim 4 characterized by that said
sensed image is processed based on the information corresponding to
the standard image for color processing of said sensed image.
9. A reproducing apparatus characterized by having a reading out
device which reads an information recorded together with another
sensed image, and corresponding to a standard image for color
processing of sensed image out of a recording medium; and a
reproducing device which reproduces another sensed image based on
the information corresponding to the standard image for color
processing of said sensed image which is read out.
10. A reproducing apparatus of claim 9 characterized by that the
standard image for color processing of said sensed image is an
image photographing an object of achromatic color.
11. A reproducing apparatus of claim 10 characterized by that the
information corresponding to the standard image for color
processing of said sensed image is the control value of white
balance obtained from the image photographing said object of
achromatic color.
12. A reproducing apparatus of claim 10 characterized by that the
information corresponding to the standard image for color
processing of said sensed image is a part of the image
photographing said object of achromatic color.
13. A reproducing apparatus of claim 9 characterized by that said
sensed image is processed based on the information corresponding to
the standard image for color processing of said sensed image.
14. A recording method characterized by: inputting a sensed image;
inputting a standard image for color processing of said sensed
image for inputting the standard image for color processing of said
sensed image; and recording an information corresponding to the
standard image for color processing of said sensed image together
connecting it with another sensed image.
15. A recording method of claim 14 characterized by that the
standard image for color processing of said sensed image is an
image photographing an object of achromatic color.
16. A recording method of claim 15 characterized by that the
information corresponding to the standard image for color
processing of said sensed image is the control value of white
balance obtained from the image photographing said object of
achromatic color.
17. A recording method of claim 15 characterized by that the
information corresponding to the standard image for color
processing of said sensed image is a part of the image
photographing said object of achromatic color.
18. A recording method of claim 14 characterized by that said
sensed image is processed based on the information corresponding to
the standard image for color processing of said sensed image.
19. A reproducing method characterized by that it reads an
information recorded together with another sensed image, and
corresponding to a standard image for color processing of the
sensed image out of a recording medium; and it reproduces another
sensed image based on the information corresponding to the standard
image for color processing of said sensed image which is read
out.
20. A reproducing method of claim 19 characterized by that the
standard image for color processing of said sensed image is an
image photographing an object of achromatic color.
21. A reproducing method of claim 20 characterized by that the
information corresponding to the standard image for color
processing of said sensed image is the control value of white
balance obtained from the image photographing said object of
achromatic color.
22. A reproducing method of claim 20 characterized by that the
information corresponding to the standard image for color
processing of said sensed image is a part of the image
photographing said object of achromatic color.
23. A reproducing method of claim 19 characterized by that said
sensed image is processed based on the information corresponding to
the standard image for color processing of said sensed image.
24. A recording medium recording a program for executing the
recording method of claim 14.
25. A recording medium recording a program for executing the
reproducing method of claim 19.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to imaging apparatus, more
particularly, to a manner of dealing with control data in signal
processing performed in reproducing apparatus or recording
apparatus.
[0003] 2. Description of the Related Art
[0004] Various types of apparatus are known for recording and
reproducing pictures in which the image signals of objects are
produced by a solid-state image sensor such as a CCD, then after
signal-processing these image signals, they are recorded on a
recording medium such as a magnetic tape and a magnetic disk. As an
example, let us take an electronic still camera which records an
object image on a recording medium as a still image. Control of
white balance (hereafter referred to as WB) for color image signals
obtained by taking the picture is an example of signal processing
performed on the image signals depending on the data representing
the condition under which a picture is taken.
[0005] Two known technologies for automatically performing WB
control are an external WB method and an internal WB method called
a TTL (Through the Lens) method.
[0006] In the external WB method, for example, the ratio of the red
(R) component to the blue (B) component is determined for the light
passing through the filters disposed on a front surface of a camera
and the resulting ratio is used as WB data. In the TTL method, on
the other hand, a picture of a reference object is taken before
taking a picture of an actual object and the image signal of the
reference object is sued to perform WB control.
[0007] Comparing these two methods of WB control, the TTL method is
generally more advantageous than the external WB method with regard
to the size and cost of apparatus. In either case, WB control is
carried out on the image signal obtained by taking a picture, and
then the image is recorded on a recording medium as image signals
color signals of which are controlled in gain to a desired
value.
[0008] One possible arrangement is to record the data for use in
signal processing such as WB control on a recording medium together
with normal image signals obtained by taking a picture. This
arrangement is useful to reduce the requirement of memory capacity
of the apparatus and to reduce the processing time required for
taking a picture, because the WB control may be performed when the
picture is reproduced.
[0009] However, in the case of such an electronic still camera in
which the control data is recorded on a recording medium, if the
recording medium is detached from the camera, the WB control data
becomes not available, and thus it becomes impossible to perform WB
control.
[0010] Furthermore, the WB control data associated with even the
same reference object will be different depending on the season and
the time when the WB data is produced, and also depending on the
location where the WB data is produced. As a result, it is very
difficult to make proper utilization of the WB control data which
is recorded on the recording medium.
[0011] On the other hand, while the TTL method has generally an
advantage in the size and cost over the external WB method, in some
cases it is impossible to perform as accurate control as required.
For example, when the object has a large magnitude of vivid color
components, the gain control of the color signals is performed such
that the vivid color components are suppressed, and thus the
reproduction from image signals obtained by taking a picture lacks
vividness in colors.
SUMMARY OF THE INVENTION
[0012] In view of the above, it is an object of the present
invention to solve the above-described problems and to provide an
imaging apparatus in which control data is produced based on state
data with regard to image signals representing the condition under
which a picture is taken, and the resulting control data as well as
image signals obtained by taking the picture is recorded on a
recording medium, whereby it becomes possible to use the control
data more often and it also becomes possible to increase the
recording capacity of image signals.
[0013] To achieve the above object, one aspect of the present
invention provides an imaging apparatus comprising image pickup
means, first memory means capable of storing an image signal
outputted from the image pickup means and condition information
representing a condition in which the image signal is picked up by
the image pickup means, second memory means capable of storing the
image signal outputted from the image pickup means and the
condition information, the second memory means being detachably
attached to the apparatus, and control means for controlling the
condition information so as to be transferred between the first
memory means and the second memory means.
[0014] Additional objects and features of the present invention
will be more readily apparent from the following detailed
description when taken in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a block diagram showing a basic configuration of
an electronic still camera in accordance with first and sixth
embodiments of the present invention;
[0016] FIG. 2 is a schematic representation of a display of a
viewfinder for use in an electronic still camera shown in FIG.
1;
[0017] FIG. 3 shows the appearance of the white balance mode
selection switch for use in an electronic still camera shown in
FIG. 1;
[0018] FIG. 4 is a flow chart of the operation with regard to the
white balance control in an electronic still camera shown in FIG.
1, mainly illustrating the operation of a system controller;
[0019] FIG. 5 is a more detailed flow chart illustrating a routine
of white paper mode setting shown in FIG. 4;
[0020] FIG. 6 is a more detailed flow chart illustrating a setting
mode routine shown in FIG. 5;
[0021] FIG. 7 is a block diagram showing a second embodiment in
accordance with the present invention;
[0022] FIG. 8 is a block diagram showing a configuration of a
camera unit of the second through fifth embodiments in accordance
with the present invention;
[0023] FIG. 9 is a schematic representation illustrating the
process for reading signals in the apparatus shown in FIG. 7;
[0024] FIG. 10 is a block diagram showing third and fifth
embodiments in accordance with the present invention;
[0025] FIG. 11 is a schematic diagram showing multiple picture
reproduction in accordance with the fourth embodiment of the
present invention.
[0026] FIG. 12 is a schematic diagram showing multiple picture
reproduction in accordance with the fifth embodiment of the present
invention;
[0027] FIG. 13 is a schematic diagram showing multiple picture
reproduction in accordance with the fifth embodiment of the present
invention;
[0028] FIG. 14 is a flow chart showing the operation with regard to
white balance correction in accordance with the sixth embodiment of
the present invention;
[0029] FIG. 15 is a block diagram showing a seventh embodiment in
accordance with the present invention;
[0030] FIG. 16 is a schematic diagram showing a configuration of a
color filter arranged with additive complementary colors;
[0031] FIG. 17 is a graph showing an example of white balance
data;
[0032] FIG. 18 is a block diagram showing another configuration in
accordance with the seventh embodiment of the present
invention;
[0033] FIG. 19 is a schematic diagram showing a configuration of a
color filter with RGB arrangement: and
[0034] FIG. 20 is a block diagram showing a further configuration
in accordance with the seventh embodiment of the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0035] Now, a first embodiment of the present invention will be
described below.
[0036] FIG. 1 is a block diagram showing a basic configuration of
an electronic still camera in accordance with the first embodiment
of the present invention.
[0037] In FIG. 1, there are shown a camera lens 1, a motor 2 for
driving the lens 1, a controller 3 of the motor 2 for driving the
lens 1, an element 4 such as a shutter and diaphragm for
controlling the amount of light, and a solid-state image sensor 5
such as a CCD. There are also provided a sample-and-hold circuit 6
for sampling and holding signals outputted from the solid-state
image sensor 5, an analog-to-digital (A/D) converter 7 for
converting the analog output signals from the sample-and-hold
circuit 6 into digital signals, a memory 8 such as DRAM, and a
memory controller 9 for controlling the operation of reading data
from the memory 8 and writing data to the memory 8 and for
controlling the refreshing operation of the DRAM.
[0038] A pulse generator 10 is also provided for generating a
timing signal for use in driving the solid-state image sensor 5, a
sample-and-hold pulse for the sample-and-hold circuit 6, and a
driving pulse for the A/D converter 7. Furthermore, there are
provided a system controller 11 for controlling the operation of
the whole system in the apparatus, and an interface 12 between a
recording medium 13 and a camera body, which will be described
later in more detail. A hard disk is used as the recording medium
13.
[0039] There are also shown a standby switch (SW1) 14 for making a
camera stand by for taking a picture, a picture-shooting switch
(SW2) 15 for commanding the camera to take a picture, an electronic
or optical viewfinder 16 detachably attached to the camera, a white
balance circuit 17 for performing WB adjustment, a WB mode
selection switch 18 for selecting the WB mode, an LED 19 for
indicating that the WB mode is set by the above WB mode selection
switch 18 to a white paper mode which will be described later in
more detail, a white-paper shooting switch 20 for giving the
command to take a picture of white paper so as to obtain the color
temperature information for use in WB control, a medium detector 21
for determining whether the recording medium 13 is attached to the
camera body, a clock device 22 for counting a time and date, and a
location detector 23 for determining where the electronic still
camera is located by means of electromagnetic waves received from
satellites.
[0040] In this embodiment, it is assumed that the WB control is
carried out by the external WB method, and there are further
provided a color sensor 24 for detecting color components in
ambient light so as to obtain WB control data, a transfer switch 26
for transferring the WB control data obtained by taking a picture
of white paper (hereinafter referred to as white paper WB data)
from the hard disk 13 used as a recording medium to the memory 8 in
the camera body, and an image processor 27 for performing the
processing such as white balance correction and gamma correction on
color image signals obtained by taking a picture.
[0041] Now, the signal flow in the electronic still camera in
accordance with the present embodiment of the invention will be
described below.
[0042] When a picture is taken to obtain the signal of an image
(still image), the image sensor 5 outputs the signal, which is
sampled and held by the sample-and-hold circuit 6, thus supplying
the color image signal. Then, the color image signal is converted
into a digital signal by an A/D converter 7.
[0043] The color image signal converted into a digital form is
temporarily stored in memory 8. The image signal stored in the
memory 8 is processed by the image processor 27, and will be
finally recorded on the recording medium 13. There may be various
options regarding when the image processor 27 performs its
operation. This operation timing adaptable for the electronic still
camera of the present embodiment depends on the configuration of
the camera. These include the following options:
[0044] (1) The image signal (data) stored in the memory 8 is read
out and processed by the image processor 27. The resulting signal
is stored again in the memory 8. Then, the image signal stored in
the memory 8 is read out again and recorded on the recording medium
13 via the interface (I/F) 12.
[0045] (2) The image signal stored in the memory 8 is read out and
processed by the image processor 27. Then, the resulting signal is
recorded on the recording medium 13 via the I/F 12.
[0046] (3) The image signal stored in the memory 8 is read out and
directly recorded on the recording medium 13 via the I/F 12. The
image signal is reproduced from the recording medium 13 via the l/F
12 and it is stored in the memory 8 again. Then it is read out
again and processed by the image processor 27. The resulting signal
is re-stored in the memory 8 again. Finally, it is read out again
and recorded on the recording medium 13 again via the I/F 12.
[0047] (4) The image signal stored in the memory 8 is read out and
directly recorded on the recording medium 13 via the I/F 12. The
image signal is reproduced from the recording medium 13 via the I/F
12 and is supplied directly to the image processor 27 so as to
perform the required processing. The processed signal is recorded
again on the recording medium 13 via the I/F 12.
[0048] (5) The image signal stored in the memory 8 is read out and
directly recorded on the recording medium 13 via the I/F 12. The
image signal is reproduced from the recording medium 13 via the I/F
12 and is supplied directly to the image processor 27 so as to
perform the required processing. The processed signal is stored
again the memory 8 and then it is read out again and recorded again
on the recording medium 13 via the I/F 12.
[0049] (6) The image signal stored in the memory 8 is read out and
directly recorded on the recording medium 13 via the I/F 12. The
image signal is reproduced from the recording medium 13 via the I/F
12 and is stored again in the memory 8. Then the signal is read out
again from the memory 8 and is processed by the image processor 27.
The resulting signal is recorded again on the recording medium 13
via the I/F 12.
[0050] The flow of the signal in WB control, which is one of
characteristic features of the present embodiment, will be describe
next. The image data for one picture obtained by taking a picture
of white paper is stored in the memory 8. Then, the image processor
27 accesses this image data for one picture and extracts portions
of the image data. This extracted data is stored again as white
paper WB data in the memory 8. The extraction method to generate
white paper WB data may be any method by which the total required
amount of information can be reduced. Such methods include (a)
extracting the image data for one line every several lines from the
image data for one picture, (b) extracting only central portion of
the image data, (c) extracting a pixel data every predetermined
constant number of pixels from the whole of the image data for one
picture.
[0051] The white paper WB data obtained in this way is transferred
from the memory 8 to the hard disk 13 via the I/F 12 as will be
described later in more detail. This leads to the reduction in the
amount of the white paper WB data recorded on the hard disk 13,
which further leads to avoidance of the great reduction in
recording capacity for color image signals obtained by taking
actual (usual) pictures.
[0052] When a still image is taken in the white paper mode, the
image signal corresponding to the still image is stored in the
memory 8. The image processor 27 gets this image signal and also
reads the white paper WB data stored in the memory 8 or recorded on
the recording medium 13. Then, the image processor 27 corrects the
white balance of the image signal corresponding to the still image
by using color temperature information which is formed from the
white paper WB data. The timing of correction may be selected from
the options (1)-(6) described above.
[0053] The color sensor (WB) 24 provides its output to the WB
circuit 17, and thus the color temperature information (outside
data) is always available. When a still image is taken in the
automatic mode, this outside data is inputted into the system
controller 11 and further supplied to the image processor 27 via
the memory controller 9. As described earlier, the image processor
27 reads the image signal corresponding to the still image stored
in the memory 8 and corrects its WB by using the outside data. This
timing of correction may also be selected from the options (1)-(6)
described above.
[0054] FIG. 2 shows a display screen of the viewfinder 16 shown in
FIG. 1. In FIG. 2, there are shown LEDs 31, 32, and 33 used for
indication. The LED 31 turns on when the WB mode selection switch
18 is set to the white paper mode. The LED 32 turns on when the WB
mode selection switch 18 is set to the setting mode. The LED 33
turns on when the generation of the white paper WB data has been
completed.
[0055] FIG. 3 shows the appearance of the WB mode selection switch
18. As shown, this switch is of the dial type and the WB control
mode can be set to any one of automatic, manual, white paper, and
setting modes by rotating the dial so that the arrow points the
corresponding position having the mark "AUTO", "MANUAL", "WHITE
PAPER", or "SET". This dial switch functions as a jumping back
switch when the dial switch is switched from the "WHITE PAPER"
position to "SET" position. Thus, the "SET" position cannot be
maintained and the selection will automatically return back to
"WHITE PAPER" unless the operator holds the dial at the "SET"
position.
[0056] In addition to the white paper mode and the automatic mode
described above, the WB control modes also include manual mode as
can be seen. In this manual mode, WB control value is manually set
to any one of four levels, (the number of levels may be less or
more than four), by manual operation means (not shown). When the
dial switch is set to "SET" position, the setting mode is selected
in which information on the color temperature can be generated by
taking a picture of white paper with the operation switch 20 for
taking a picture of white paper. Thus, it is possible to take a
picture of white paper and to generate the information on the color
temperature (white paper data).
[0057] FIG. 4 is a flow chart showing the operation associated with
the white balance control in an electronic still camera shown in
FIG. 1, in which the operation of the system controller 11 is
mainly illustrated. FIG. 5 is a more detailed flow chart
illustrating a routine for setting the white paper mode shown in
FIG. 4. FIG. 6 is a more detailed flow chart illustrating a setting
mode routine shown in FIG. 5. Referring to these flow charts shown
in FIGS. 4-6, the operation with regard to the WB control will be
described below.
[0058] The flow chart of FIG. 4 starts with step S101 when a power
switch (not shown) is turned on. This step S101 determines whether
the hard disk (HDD) 13 is attached or not, judging from the output
of the medium detector 21. If the HDD 13 is not attached, then the
operation moves to step S107 which determines whether the white
paper data is recorded in the memory 8 installed in the camera
body. If there is no white paper data recorded in the memory 8,
then the operation returns to step S101.
[0059] In step S107, if the conclusion is that there exists the
white paper WB data recorded in the memory 8, then the routine
enters into step S108 to wait for the HDD 13 to be attached. After
completion of the attachment of the HDD 13, the HDD 13 is started
up in step S109, and then in step S110, the white paper WB data
stored in the memory 8 is transferred to the HDD 13 via the I/F 12.
After that, in step S111, the HDD 13 is stopped. Then, the routine
proceeds to step S102.
[0060] In the above steps, if the HDD 13 is not attached, this
means that the camera is not in the operation of taking a picture
or otherwise the HDD 13 becomes full of data during operation of
taking a picture and there is no room for further data. In the
latter case, it is possible to directly use the white paper WB data
detected previously. In this case, as will be described later, just
prior to the detachment of the HDD 13, the white paper WB data
recorded on the HDD 13 is transferred to the memory 8. Thus, when
the HDD 13 full of data is detached, the white paper WB data is
always left in the memory 8. In step S110, this white paper WB data
is recorded on a HDD 13 which is newly attached.
[0061] If the conclusion in step S101 is that the HDD 13 is
attached already, or if the HDD 13 has been attached newly, then
decision is made in step S102 whether the WB mode selection switch
18 is set to the white paper mode. If the white paper mode is not
selected, then whether the WB mode selection switch 18 is set to
the automatic mode is determined in step S104. In these steps S102
and S103, the selection of the WB mode selection switch 18 is
definitely determined, that is to say, it is determined which dial
position of "WHITE PAPER", "AUTO", or "MANUAL" is selected. If it
is detected in step S104 that the automatic mode is selected, then
the WB control is set to the automatic mode in step S105. If it is
concluded in step S104 that the automatic mode is not selected,
then it is considered that the dial position is set to "MANUAL" and
in step S105 the WB control is set to the manual mode described
above.
[0062] If it is concluded in step S102 that the WB mode selection
switch 18 is set to the white paper mode, then the routine proceeds
to step S103 in which the white mode setting routine is carried
out.
[0063] As shown in FIG. 5, in step S201 of the white paper setting
routine, it is determined first whether the camera is in usual
operation mode for taking a picture. If the camera is in usual
operation, then the routine waits for completion of the usual
operation. If the camera is not in usual operation or if the usual
operation has been completed, the routine proceeds to step S202 in
which the LED 31 blinks to indicate that the WB mode selection
switch 18 is set to the white paper mode.
[0064] Alternatively, in step S202, the LED 31 may be lit
continuously instead of blinking, or it may be arranged that a
warning sound is generated. Otherwise, the combination of these may
also be possible.
[0065] In a case where the white paper WB data is produced for the
first time by taking a picture of white paper, no white paper WB
data is recorded on the HDD 13 or stored in the memory 8.
Therefore, in step S203, decision is made whether the white paper
WB data exists in the memory 8 or on the HDD 13, and if there
exists no such data, then the routine proceeds to step S204 so as
to perform the setting-mode routine in which the white paper WB
data is surely established.
[0066] On the other hand, if the white paper WB data already exists
in the memory 8 or on the HDD 13, it is possible to perform the WB
control by using this white paper WB data. Thus, except for the
case in which the conclusion in step S206 indicates that the WB
mode selection switch 18 is set to the setting mode, the routine
proceeds to step S207 in which the WB control is set to the white
paper mode, and then the routine returns to the main routine.
[0067] When step S203 concludes that no white paper WB data exists
in the memory 8 or on the HDD 13, or when step S206 concludes that
the WB mode selection switch 18 is set to the setting mode, the
routine enters into step S204 so as to perform the setting-mode
routine.
[0068] In this setting-mode routine, the white paper WB data is
established as will be described in more detail hereinbelow, then
the routine returns to the main routine.
[0069] Referring to the flow chart shown in FIG. 6, the
setting-mode routine will be described. In the first step of the
setting-mode routine, S301, the LED 32 blinks to indicate that the
WB control is in the setting mode. Then, in step S302, the routine
waits for the operation switch 20 used for taking a picture of
white paper to be turned on. In this case, the decision is made in
step S306 whether the white paper WB data exists in the memory 8 or
on the HDD 13.
[0070] If no white paper WB data exists, it is required to newly
produce white paper WB data. Thus, in this case, the routine
returns to step S302 so as to further wait for the operation switch
20 used for taking a picture of white paper to be turned on. On the
other had, if the white paper WB data already exists in the memory
8 or on the HDD 13, this means that the WB mode selection switch 18
is set to "SET" position, that is to say, it is desired to update
the white paper WB data. However, if the operation switch 20 used
for taking a picture of white paper is not turned on for a
predetermined time, the data is not updated. In this case, the
routine proceeds to step S307 so as to determine whether the
counted value of the counter in the system controller 11 reaches a
predetermined value. If the counted value is less than the
predetermined value, the value is incremented in step S308. If the
counted value reaches the predetermined value with no event of
turning-on of the operation switch 20 used for taking a picture of
white paper, then the routine proceeds to step S309 in which the
counter is reset without any new setting of the white paper WB
data, and thus the routine automatically cancels the setting
mode.
[0071] If, in step S302, the operation switch 20 used for taking a
picture of white paper is turned on, the routine proceeds to step
S303 in which a picture of white paper is taken by operating the
image sensor 5 and other required devices so as to produce new
white paper WB data and the resulting data is stored in the memory
8. Further, in step S304, the information on the time and data
obtained from the clock device 22, the information of the location
on the earth obtained from the location detector 23 and the white
paper WB data newly produced, are all together recorded on the HDD
13 via the I/F 12.
[0072] After that, in step S305, the LED 33 turns on to indicate
the completion of taking a picture of white paper. Again in this
step S305, alternatively, the LED 33 may blink instead of
continuously lighting, or it may be arranged that a warning sound
is generated, or the combination of these may also be possible.
[0073] After these steps are completed, the routine passes via step
S309 to step S310 in which the LED 32 used for indication that the
WB control is in the setting mode and the LED 33 used for
indicating the completion of taking a picture of white paper are
both turned off. Then, the routine returns to step S206 in the
white paper mode setting routine. That is to say, the routine
returns to the main routine after the WB control mode is set to the
white paper mode.
[0074] In these steps described above, the WB control mode is
determined. In this situation, by operating the standby switch SW1
(14) and the operation switch SW2 (15) for taking a picture, it is
possible to perform the usual operation for taking a still image in
the specified WB control mode. That is to say, step S112 determines
whether the standby switch SW1 (14) is turned on. If the conclusion
is positive, the routine proceeds to step S113 so as to make the
operation be in the standby mode for taking a picture by operating
autofocussing function and autoirising function.
[0075] In this standby mode, step S114 determines whether the
operation switch SW2 (15) used for taking a picture is turned on.
If the operation switch SW2 is turned on, a still image is taken in
step S116. Step S115 detects the occurrence of turning-off of the
standby switch SW1 (14) before the occurrence of turning-on of the
operation switch SW2 (15) for taking a picture. Upon this
occurrence, the routine returns to step S112. Step S117, determines
whether both of the standby switch SW1 (14) and the operation
switch SW2 (15) for taking a picture are turned off after
completion of taking a still image. If the conclusion is positive,
the routine returns to step S101.
[0076] After the WB control mode has been set as previously
described, step S118 determines whether the HDD 13 is attached to
the camera body. If the HDD 13 is attached, decision is made in
step S119 whether the transfer switch 26 is turned on. If the
conclusion is positive, the routine proceeds to step S120. If the
HDD 13 is not attached, or if the transfer switch 26 is not turned
on, then the routine returns to step S101.
[0077] The transfer switch 26 is operated to transfer the white
paper WB data stored on the HDD 13 to the memory 8 before the HDD
13 is detached for exchange. When the transfer switch 26 is turned
on, decision is made in step S120 whether the white paper WB data
is recorded on the HDD 13. If there is no such data, no operation
occurs and the routine proceeds to step S124. In step S124, when
turning-off of the transfer switch 26 is confirmed, the routine
returns to step S112.
[0078] If step S120 concludes that the HDD 13 has the white paper
WB data, the routine proceeds to step S121 to start up the HDD 13.
Further, in step S122, the white paper WB data recorded on the HDD
13 is transferred to the memory 8 via the I/F 12. After that, in
step S123, the HDD 13 is stopped. Then, in step S124 if turning-off
of the transfer switch 26 is detected, the routine returns to step
S112.
[0079] After the white paper WB data recorded on the HDD 13 which
is going to be detached for exchange is transferred to the memory 8
in the camera body as described above, another HDD is attached.
Then, in steps S107-S111 as described above, the white paper WB
data is automatically transferred to the newly attached HDD. Thus,
the white paper WB data is inherited.
[0080] With the arrangement described above, even in a case where
the HDD 13 is detached, the WB control data stored in the memory 8
can be used to perform the WB control. Besides, the WB control data
can be inherited when the HDD 13 is exchanged. Thus, it becomes
possible to increase the opportunity to use available white paper
WB data and it also becomes possible to increase the possibility of
performing better WB control.
[0081] When the white paper WB data is produced in the WB setting
mode for the above electronic still camera, if a picture of the
white paper is taken with illumination of a fluorescent lamp in a
room, the flicker of the fluorescent lamp may be detected so as to
reduce the influence of the flicker by setting the shutter to the
proper speed depending on the detected flicker. For example, the
shutter speed may be set to an integer multiple of the flicker
cycle. Alternatively, when the flicker cycle is given as a constant
value such as {fraction (1/100)} sec. or {fraction (1/120)} sec.,
the shutter speed may be set to for example {fraction (1/20)}
sec.
[0082] In the embodiment described hereinabove, an HDD is used as a
recording medium. However, alternatively, a semiconductor memory
card or other type magnetic recording medium may be also used in an
imaging apparatus in accordance with the present invention.
[0083] In accordance with the present embodiment of the invention,
as described above, the WB control data is generated from the color
image signal outputted from the image pickup means. When the
attachment of the recording medium is detected, correspondingly the
WB control data is read from the internal memory means and is
recorded on the recording medium. In addition, the WB control data
recorded on the recording medium may be transferred to the internal
memory means. Thus, even if the recording medium is detached, the
WB control data stored in the internal memory means may be used to
perform WB control. Besides, the WB control data may be inherited
when the HDD 13 is exchanged. Thus, it becomes possible to increase
the opportunity to use available white paper WB data and it also
becomes possible to increase the possibility of performing better
WB control.
[0084] When the color image signal outputted from image pickup
means is recorded as WB control data on the recording medium, only
a portion of the color image signal may be recorded as the WB
control data so as to minimize the reduction in the recording
capacity for color image signals for usual pictures.
[0085] Now, a second embodiment of the present invention will be
described hereinbelow.
[0086] In the first embodiment, the WB control data is generated
and recorded together with the image signals. However, in some
cases, as previously described, sufficiently high accuracy control
cannot be achieved. This second embodiment provides an imaging
apparatus which can overcome this disadvantage.
[0087] In this embodiment, an electronic still camera will be taken
again as an example to which the present invention is applied. FIG.
7 shows a video reproducing apparatus in accordance with the second
embodiment of the present invention.
[0088] In FIG. 7, there is shown an HDD 701 which is detachably
attached to the video reproducing apparatus and which is used as a
video recording medium. There are also shown a controller 702 for
controlling the whole of apparatus including the HDD 701, a memory
703 used for storing the video signal read from the HDD 701 under
the control of the controller 702, an adder 704 by which signals
read from the memory 703 are added to each other as described
later, and a luminance signal processing circuit 705 for processing
the signals outputted from the adder 704 so as to produce a
luminance signal Y.
[0089] A color signal processing circuit 706 is also shown in FIG.
7 for producing color signals R.sub.1, G.sub.1, and B.sub.1 from
the video signal provided from the adder 704. A variable gain
amplifier 707 controls the gains of respective color signals
R.sub.1, G.sub.1, and B.sub.1 and outputs the resulting signals R,
G and B. There are also provided a matrix circuit 708 for
performing matrix processing on the color signals R, G, and B so as
to produce color-difference signals R-Y and B-Y, an encoder 709 for
producing a composite video signal from the color-difference
signals R-T, B-Y and the luminance signal Y described above, a D/A
converter 710 for converting the composite video signal to an
analog signal, an adder 711 for adding a synchronizing signal from
the controller 702 to the composite video signal which has been
D/A-converted, a driver 712 which inputs the composite video signal
added with the synchronizing signal and which operates under the
control of the controller 702, a monitor 713 for displaying a video
image under the control of the driver 712, and an operation unit
719 used for operating various switches.
[0090] Furthermore, there are shown a data detection unit 714 which
detects the designation data associated with WB, which will be
described later in more detail, from the signal read from the HDD
701 so as to provide the detected designation data to the
controller 702, a color temperature detection unit 715 for
detecting the color temperature of the video signal from the
previously described color-difference signals R-Y and B-Y under the
control of the controller 702, and a hold circuit 716 for holding
the detected color temperature which is used as the WB control
value for controlling the gain of the variable gain amplifier
707.
[0091] FIG. 8 shows a camera unit for taking a picture of an object
and for recording the image of the object on the HDD 701 previously
described. The HDD 701 is detachably attached to the camera unit.
After the image data associated with the pictures taken by the
camera unit is recorded on this HDD 701, the HDD 701 is detached
from the camera unit and attached to the video reproducing
apparatus shown in FIG. 7 to reproduce the images. Alternatively,
the camera unit may be arranged in an integral form with the video
reproducing apparatus.
[0092] In FIG. 8, there are shown a controller 720 for controlling
the total system of the camera unit, an optical system 721
including a lens, a diaphragm and the like, an image pickup part
722 including a CCD used as an image sensor. This CCD has color
filters such as those shown in FIG. 9 arranged for each pixel. As
shown, the color filter comprises two types of lines: one comprises
Mg (magenta) and G (green) which are arranged alternatively, and
the other one comprises Cy (cyan) and Ye (yellow) which are
arranged alternatively, wherein the location alternates between Mg
and G line to line to form so-called checkered arrangement with
additive complementary colors.
[0093] There are also shown an A/D converter 723 for performing A/D
conversion on the signal obtained by photoelectric conversion with
the image pickup part 722, and a memory 724 such as a semiconductor
memory for storing image data for one picture in the digital form
obtained by photoelectric conversion with the above CCD.
Furthermore, there is provided an adder 725 which adds the signal
read from the memory 724 to the designation data associated with WB
from the controller 720 and which outputs the resulting signal so
as to record it on the HDD 701. An operation unit 726 is also shown
which has various switches including a designation switch used for
producing designation data.
[0094] Now, the operation in the above arrangement will be
described below.
[0095] In this embodiment, a plurality of pictures are taken with
the camera unit shown in FIG. 8 and a plurality of video signals
thereof are recorded on the HDD 701. One of these video signals is
designated as a reference video signal, which is to be used as
reference to produce the control data for WB control in reproducing
process. Then, the designation data representing the above fact,
the reference video signal, and the location data representing the
location thereof are all together recorded on the HDD 701. As for
the other remaining video signals, the designation data
(corresponding to the location data of the reference video signal)
designating the location of the video signal which is to be used as
the reference video signal to perform WB control when reproducing
it, is recorded together with respective video signal.
[0096] In the above procedure, the signal obtained by taking a
picture for example to a neutral gray reference board or an object
including a large amount of white components is used as the
reference video signal.
[0097] In reproduction, the reference video signal is taken from
the above plurality of video signals and it is reproduced so as to
obtain the WB control data. This control data is used to determine
the gain of the variable gain amplifier 707. When the other video
signals are reproduced, WB control is performed by using this WB
control data.
[0098] Now, detailed descriptions will be given hereinbelow on the
operation of recording and reproducing.
[0099] In the camera unit shown in FIG. 8, the operation unit 726
has a switch 726a used for determining whether the signal which is
about to be obtained by taking a picture is designated as the
reference video signal used as the WB control data in reproduction.
There is also provided a switch 726b which is used, in the case the
switch 726a is set such that the signal which is about to be
obtained by taking a picture is not adopted as the reference video
signal, to designate which of video signals will be used as the
reference video signal. These switches may be set by an operator
before taking a picture of an object. When a video signal is stored
on the HDD 701, the information established by setting these
switches is provided as designation information from the controller
720 to the adder 725, and then this information is recorded on the
HDD 701 when the video signal is recorded. With reference to FIG.
8, when a release switch in the operation unit 726 is operated, the
controller 720 controls the diaphragm in the optical system 721 and
determines the exposure time so as to give a proper exposure to the
CCD in the image pickup part 722. In this way, the optical system
721 and the image pickup part 722 are controlled. Then, the signal
is read from the properly exposed CCD, and the resulting signal is
inputted to the A/D converter 723 in which the electrical signal
corresponding to an individual pixel of the CCD is converted into a
digital signal. The signal corresponding to the pixel of the CCD
from the A/D converter 723 is inputted to the memory 724, and is
stored temporarily in it.
[0100] Then, the signal is transferred from the memory 724 to the
HDD 701. Prior to the reading of a signal from the memory 724, the
controller 720 outputs the designation data which represents
whether the signal being obtained at that time by taking a picture
will be used as the reference video signal in reproduction to
produce the WB control data and which represents the recording area
(location) where the reference video signal to be used in
reproduction is recorded in the case in which the above signal
obtained at that time by taking a picture will not be used as the
reference video signal. This designation data from the controller
720 is recorded on the HDD 701 at the prescribed recording area
(location). Then, the controller 720 controls the memory 724 and
reads the signal stored in the memory 724. Further the controller
720 records this signal on the HDD 701 at the prescribed recording
area via the adder 725.
[0101] As described above, the video signal obtained by taking a
picture with the camera unit is recorded on the HDD 701 together
with the designation data associated with the WB control. Then, the
HDD 701 on which the video signal is recorded is detached from the
camera unit and attached to the video reproducing apparatus shown
in FIG. 7 to reproduce the video signal. Now, this operation will
be described below.
[0102] With reference to FIG. 7, when the operation unit 719 issues
a command to reproduce a certain video signal, the controller 702
reads the signals from the HDD 701. The designation data with
regard to the WB control for the recorded video signals is read
first. This designation data is detected by the data detection unit
714 and is further inputted to the controller 702.
[0103] Then, the controller 702 determines whether the video signal
designated to be reproduced is the reference video signal. If this
signal is designated as the reference video signal, then the data
of this video signal for one frame is read from the HDD 701 and
stored in the memory 703. The location data representing the
recording area of this video signal is stored in the controller
702. Control is performed on the video data for one frame stored in
the memory 703 so that the data corresponding to two lines of the
image sensor in the camera unit may be read out at the same
time.
[0104] More specifically, as shown in FIG. 9, when the first field
is read out, a pair of lines 1 and 2, lines 3 and 4, . . . , or
lines 2n+1 and 2(n+1) are read at the same time, and when the
second field is read out, a pair of lines 2 and 3, lines 4 and 5, .
. . or lines 2n and 2n+1 are read out from the memory 703, and the
signals read out are added to each other with the adder 704. The
output signal of the adder 704 is applied to the luminance signal
processing circuit 705 as well as to the color signal processing
circuit 706. In the luminance signal processing circuit 705, the
luminance signal is generated from the input signals associated
with Mg, G, Cy, and Ye, and the resulting signal is applied to the
encoder 709. On the other hand, the color signal processing circuit
706 generates the signals R.sub.1, G.sub.1, and B.sub.1 from the
input video signal and provides these signals to the variable gain
amplifier 707.
[0105] In this situation, the controller 702 relieves holding
operation of the hold circuit 716 which controls the gain of the
variable gain amplifier 707 so that the output signal of the color
temperature detection unit 715 is directly outputted from the hold
circuit 716. That is to say, when the present video signal is
processed successively after the previous video signal, the latest
output signal which was used to process the previous video signal
is still provided as the output signal from the color temperature
detection unit 715, and this signal is applied as the control input
signal via the hold circuit 716 to the variable gain amplifier 707.
Gain control of the variable gain amplifier 707 is performed on
each amplifier associated with input signals R.sub.1, G.sub.1, and
B.sub.1 depending on each gain control signal.
[0106] Then, the gain-controlled R, G, and B signals are inputted
to the matrix circuit 708 from the variable gain amplifier 707. The
matrix circuit 708 produces the R-Y and B-Y signals by using known
matrix processing and outputs the resulting signals. The R-Y and
B-Y output signals are inputted to the encoder 709 and also to the
color temperature detection unit 715. The color temperature
detection unit 715 performs integration of the R-Y and B-Y input
signals over one field period, and updates via the hold circuit 716
the control signal for the variable gain amplifier 707 every field.
Thus, the gains for R, G, and B signals are controlled so that the
integrated values of R-Y and B-Y signals become nearly zero. That
is to say, a control loop is formed through the variable gain
amplifier 707, the matrix circuit 708, the color temperature
detection unit 715 and the hold circuit 716, and this control loop
functions such that the integrated values taken over a period of
one field on R-Y and B-Y signals become nearly zero. Thus, the WB
control is performed through this control loop.
[0107] The R-Y and B-Y signals as well as the Y signal from the
luminance signal processing circuit 705 are inputted to the encoder
709, which produces the composite video signal. The produced
composite signal is converted into an analog signal with the D/A
converter 710. Then, in the adder 711, the synchronization signal
from the controller 702 is added to the output signal from the D/A
converter 710 and the resulting signal is applied to the driver
712. The driver 712 outputs this signal as the video signal to be
displayed on the monitor 713.
[0108] The operation is performed in a manner described above, when
the video signal read from the HDD 701 is designated by its
associated designation data as the reference video signal. On the
other hand, when the video signal is not designated by its
associated designation data as the reference video signal, the
operation will be performed in such a way as will be described
below.
[0109] In such a case, it is possible to use the location data
recorded as the designation data representing the recording area
where the reference video signal for the video signal read from the
HDD 701 is recorded. Therefor, the data detection unit 714 detects
this location data. This detected location data representing the
recording area associated with the video signal is compared with
the location data representing the recording area of the video
signal stored in the controller 702, that is to say, the location
data representing the recording area of the reference video signal
which was previously used to perform the WB control. If these data
are identical, the controller 702 makes the hold circuit 716 be in
holding operation so that the hold circuit 716 holds the value
outputted at that time output from the color temperature detection
unit 715 and so that the hold circuit 716 continues to output this
value to the variable gain amplifier 707. That is to say, by using
the same control data without newly re-performing WB control, the
WB control will be maintained on the video signal which is about to
be read out.
[0110] Subsequently, the controller 702 reads the video signal
specified to be reproduced from the HDD 701 and writes it in the
memory 703. In the similar way to the case described above, the
video signal processing is carried out and the driver 712 outputs
the video signal on which the reproduction processing has been
performed. In this processing, as described above, the WB control
is performed without outputting a new signal from the color
temperature detection unit 715 to the variable gain amplifier 707
via the hold circuit 716. However, the existing value which has
been held at the value of the pervious output signal from the color
temperature detection unit 715 is applied to the variable gain
amplifier 707. Thus, the control signal is maintained at the
constant value.
[0111] Now, the operation will be described below for the case
where the location data representing the recording area associated
with the video signal which is going to be used for the WB control
of the video signal to be reproduced is different from the location
data stored in the controller 702 representing the recording area
associated with the reference video signal previously used for the
WB control.
[0112] In this case, the controller 702 maintains therein the
location data representing the recording area of the video signal
used for performing the WB control and the controller 702 reads the
reference video signal recorded in this recording area so as to
write it in the memory 703. Then, the video signal written in the
memory 703 is read out and the WB control is performed on it. That
is to say, this time, the controller 702 relieves the holding
operation of the hold circuit 716. Thus a new color temperature is
detected and the control loop described above becomes in operation
for controlling the variable gain amplifier 707. However, in this
situation, the controller 702 controls the driver 712 so that the
driver 712 becomes in a muting state in which the reproducing video
signal is not provided from the output terminal.
[0113] When the WB control is completed in a manner as described
above, the controller 702 makes the hold circuit 716 be in a
holding operation so as to hold the WB control value at that time.
Then, the video signal specified to be reproduced is read out from
the HDD 701 and written in the memory 703. Then, the signal is read
out from the memory 703 and is reproduction-processed without
updating the WB control data. Furthermore, the controller 701
relieves the muting state of the driver 712 so as to provide the
reproducing video signal from the output terminal.
[0114] When signal processing is performed on the video signal for
the WB control which is carried out prior to performing of the
signal processing on the video signal specified to be reproduced,
portions of the video signal may be used, instead of using all of
one picture data of the video signal.
[0115] Extracting portions from the total video signal may be
carried out when the video signal is transferred from the HDD 701
to the memory 703 or when the video signal is read out form the
memory 703.
[0116] FIG. 10 shows a third embodiment in accordance with the
present invention. The same or similar elements as those in the
case of FIG. 7 are denoted by the same numerals, and these elements
will not be explained again.
[0117] With reference to FIG. 10, the apparatus in accordance with
this embodiment has a computing circuit 717 to which the signal
read out from an HDD 701 is provided. This computing circuit 717
has a variable delay line with the maximum delay time corresponding
to 1 H (horizontal scanning period) of a CCD shown in FIG. 9, and
performs addition between the signals of different lines obtained
from the CCD. There is also provided a memory 718 to which the
composite video signal is inputted from the encoder 709. Write/read
operation to and from the memory 718 is performed under the control
of the controller 702.
[0118] Now, the operation which will be performed when a command is
given to the controller 702 to reproduce a video signal will be
described below. First, before reading the video signal from the
HDD 701, the controller 702 obtains the designation data associated
with the WB control for the video signal from the data detection
unit 714. When the designation data obtained from the data
detection unit 714 designates a signal as a reference video signal
which is recorded in a different area, this designated reference
video signal should be read out first. In this reading process, the
controller 702 sets the delay time of the variable delay line to
1/2 H and reads the video signal from the HDD 701 by extracting
half the horizontal line. The extracted signal is inputted to the
computing circuit 717. The computing circuit 717 performs addition
between the data of different lines and outputs the result to the
color signal processing circuit 706 as well as to the luminance
signal processing circuit 705. In the later processing, the output
signal of the color temperature detecting unit 715 will be held so
as to produce the WB control data, and, however, at this stage, the
output signal of the encoder 709 is not written in the memory
718.
[0119] Then, the controller 702 reads the video signal specified to
be reproduced from the HDD 701 and sets the delay time of the
variable delay line in the computing circuit 717 to 1 H. The
addition processing between different line data is performed on the
video signal read out in this way and the result is outputted.
Furthermore, other processing is performed and the composite video
signal is outputted to the memory 718 form the encoder 709. This
time, the controller 702 controls the memory 718 so that the output
signal of the encoder 709 is written in the memory 718. Thus, the
reproduction-processed video signal is written in the memory
718.
[0120] Then, the controller 702 reads the video signal form the
memory 718. The adder 711 adds this video signal and the
synchronizing signal. Then, the signal is outputted as the
reproducing image signal from the driver 712 to the monitor
713.
[0121] When it is commanded to reproduce another video signal for
which different video signal is designated as the reference vide
signal, the controller 702 continues to read the signal stored in
the memory 718 while the processing is performed to obtain the WB
control data, until new control data is obtained. Then, when the
signal processing on the video signal specified to be reproduced is
performed, the controller updates the contents of the memory 718 so
as to switch the output of the reproducing video signal. In this
way, the reproducing video signal can be switched without giving
strange feeling.
[0122] Now, a fourth embodiment in accordance with the present
invention will be described below.
[0123] In this embodiment, a plurality of video signals which
designate the same reference video signal as the reference video
signal used to perform white balance control are taken into one
group and are reproduced at the same time on the same screen as
shown in FIG. 11. The number of windows (area of sub screen) which
can be displayed at the same time may be selected from 4, 9, 16,
and 25 with a window number selection switch. As an example,
multiple picture reproduction comprising four windows A, B, C, and
D as shown in FIG. 11 will be described below.
[0124] With reference to FIG. 7, in such a multiple picture
reproduction mode, the controller 702 reads the signal from the HDD
701 and the designation data is detected in the data detection unit
714. After the designation data, the reference video signal is read
out, and then a video signal which is designated by the designation
data as that for which the WB control should be performed using the
above reference video signal is transferred to the area in the
memory 703 corresponding to the area A of FIG. 11. When the video
signal is transferred from the HDD 701 to the memory 703, reduction
or partly extracting of the video signal is performed depending on
the number of the multiple reproducing windows. In this example,
after reducing the data to a half for each of H and V directions,
the reduced data is transferred to the memory 703.
[0125] Then, the controller 702 further reads from the HDD 701 the
designated data in a different recording area and retrieves the
video signal included in the same group as that in which the video
signal previously transferred to the memory 703 is included.
[0126] When the video signal reads the designated data of the video
signal included in the same group as a result of the retrieval,
subsequently the data is reduced to 1/2 on this video signal for
both of H and V directions and the reduced data is transferred in
the area of the memory 703 corresponding to the area B of FIG. 11.
Further retrieval is repeated so as to transfer the video signals
included in the same group to the areas corresponding to the areas
C and D, respectively, after performing the data reduction.
[0127] In this way, when these video signals with reduced data size
for four windows having one full screen data size as a whole are
stored in the memory 703, the controller 702 starts to read the
video signals from the memory 703 in a similar manner as in the
above case. In this situation, the period of integration processing
performed in the color temperature detection unit 715 on the R-Y
and B-Y signals provided from the matrix circuit 708 is such a
period during which the reference video signal is read from the
memory 703, that is to say, the period during which the data
corresponding to the area A of FIG. 11 is read out, and thus the
color temperature detection is performed by using only this
reference video signal. Furthermore, the gain control of the
variable gain amplifier 707 is performed via the hold circuit 716.
In this way, when the operation in the control loop is settled, the
controller 702 makes the hold circuit 716 be in holding operation
so that the hold circuit 716 continues to provide the value which
is outputted at this time from the color detection unit 715. Based
on this output value, the WB control is performed and the gain
control of the variable gain amplifier 707 is controlled. Thus, the
driver 712 provides the output reproducing video signals with white
balance, comprising four windows of multiple screens, so as to
display these video signals on the monitor 713 as shown in FIG.
11.
[0128] Furthermore, when a command is given to the controller 702
to switch the reproducing signals, the controller 702 retrieves a
video signal in different recording areas again and transfers the
reference video signal to the memory 703 so as to update the video
signal in the area corresponding to the area A. Then, retrieval is
continued for the video signal in the HDD 701 so as to successively
transfer the data to the areas B, C, D. After that, the video
signals are successively read out from the memory 703 so as to make
reproduction of multiple pictures.
[0129] If the retrieval is completed for all recording areas in the
HDD 701 during the retrieval of the video signals, in other words,
before the transfer of the video signals to all the areas A, B, C,
and D of FIG. 11 is completed, the controller 702 writes gray level
signals in the remaining areas.
[0130] As described above, reproduction of multiple pictures is
done with video signals belonging to a group in which all video
signals designate the same reference video data as the video signal
to determine the WB control data. In this reproduction, the
reference video signal which was designated for the picture in the
first window is used to perform WB control. The control data
obtained in this way is held and this same control data is further
used for other pictures in multiple windows.
[0131] When more large number of multiple windows such as 16 and 25
windows is selected in the multiple picture reproduction, one full
screen data of a video signal for performing the WB control is
stored in the memory 703 without performing any data reduction, or
a predetermined data size of video signal is stored in the memory
703. Then, this video signal is read out from the memory 703 so as
to determined the WB control data and the resulting WB control data
is held. After that, the video signals for a desired number of
windows are stored in the memory 703 after performing data
reduction. These stored video signals are read out so as to
generate reproducing video signals. In this way, good WB control
can be achieved even in multiple picture reproduction with a large
number of windows.
[0132] A fifth embodiment of the present invention will be
described below.
[0133] In this embodiment, when a picture is taken, the designation
data described above associated with the WB is not recorded.
However, when reproduction is performed, the selection is made for
each of video signals to be reproduced whether the video signal
itself is designated as the reference video signal or another video
signal is designated as the reference video signal. The selection
switch for this purpose is provided in the operation unit 719. In
this embodiment, the circuit is configured as shown in FIG. 10.
[0134] When a video signal is specified to be reproduced with the
operation unit 719 and this video signal itself is designated as
the reference video signal, this video signal is read out from the
HDD 701 and the color temperature is detected in a similar manner
as in the cases described above, and further the control loop
described above is established so as to determine the WB control
data. Thus, the reproducing video signal on which WB control is
performed using this control data is obtained.
[0135] As long as the WB control is performed through the control
loop, the video signal which was previously processed and has been
stored in the memory 718 shown in FIG. 10 is continuously read out
and displayed on the monitor 713.
[0136] Next, the operation will be described below in the case
where the WB control data is obtained from the specified reference
video signal and reproducing processing is carried out based on
this control data.
[0137] When the operation unit 719 commands the controller 702 to
reproduced multiple pictures as shown in FIG. 12, the controller
702 reads video signals from the HDD 701 and performs reproduction
processing on these signals in a manner as described above. Thus,
WB control and other required processing are performed on the video
signals and these video signals are written in the memory 718. In
this writing process, after data reduction is performed on the
signals outputted from the encoder 709 depending on the number of
windows for reproduction of multiple pictures, the reduced video
signals are stored in the memory 718. With reference to FIG. 12, as
an example, reproduction of multiple pictures comprising 25 windows
will be described below, although the number of the windows is not
limited to 25. In this case, the signal to be written in the memory
718 is reduced to {fraction (1/25)}, and then the reduced signal is
written. In this writing process, the signal is stored in the area
designated by "1" located on the top and left side in FIG. 12,
which is one of 25 divided areas from a full screen.
[0138] Then, another video signal is read out from the HDD 701. WB
control through the WB control loop is performed on this video
signal, and then data reduction is carried out and the reduced
video signal is stored in the area of the memory 718 shown as "2"
in FIG. 2. In a similar manner, video signals are successively
stored in the memory 718 at the areas corresponding to those areas
denoted by "3"-"25" as shown in FIG. 12. In this way, each of video
signals for 25 windows is subjected to WB control and data
reduction, then written in the memory 718.
[0139] When all of 25 windows are written, the controller 702 reads
data from the memory 718 and outputs it. These signals are provided
as multiple picture video signals comprising 25 windows to the
monitor 713 from the driver 712 via the D/A converter 710. At this
stage, watching the screen of the monitor 713, the operator
designates a reference video signal to be used to obtain the WB
control data. This can be done by specifying the number denoting
any of the 25 divided areas. Alternatively, the desired area may be
selected with a mouse.
[0140] After designating the reference video signal, the operator
selects a video signal from 25 windows to be displayed by using the
control data obtained from this reference video signal. When the
controller 702 receives this command via the operation unit 719,
the controller reads the reference video signal again from the HDD
701 and performs WB control on this video signal in a manner as
described above. After completion of WB control, the controller 702
makes the hold circuit 716 be in holding operation so as to hold
the output of the color temperature detection unit 715. At this
time, the processed reference video signal is not written in the
memory 718.
[0141] Then, the video signal selected to be reproduced is read out
from the HDD 701 and processed. In this processing, by using the WB
control data obtained by processing the reference video signal, the
gain control is performed for each of R, G, and B signals, and then
the controlled video signal is stored in the memory 718. When one
screen of data is written, the data is read out and displayed on
the monitor 713.
[0142] As described above, a reference video signal to be used to
obtain the WB control data is selected from video signals displayed
in multiple windows, then based on the WB control data obtained by
processing the selected signal, the reproduction processing is
performed on the video signal which is selected to be reproduced.
Then, this video signal is displayed on the monitor 713. In this
example, the reference video signal is processed again after
multiple window reproduction. Instead, the controller 702 may store
the control data for each of the video signals obtained when
displaying them in multiple windows so as to use the stored control
data. That is to say, the control data corresponding to the
selected reference video signal is retrieved from the control data
stored in the controller 702 for each of the video signals and the
obtained control data is used to control the gain of R, G, B
signals for the video signal selected to be reproduced.
[0143] A way to select a reference video signal by using a small
size window inserted in a full screen as in FIG. 13 will be
described next.
[0144] With the operation unit 719, the above-mentioned
reproduction processing is performed picture by picture. An
operator watches these pictures on the monitor 713. At this stage,
the operator can designate a video signal reproduced on the monitor
713 as a reference video signal to be used to obtain control data.
This designation can be done by operating the WB selection switch
provided on the operation unit 719. If this WB selection switch is
operated, the control data used for processing this video signal
displayed on the monitor 713 is held in the hold circuit 716.
Furthermore, data is written in the memory 718 so that the video
signal reproduced at that time on the screen may be displayed in
the small window denoted by A in FIG. 13.
[0145] Subsequently, when another video signal is newly selected to
be reproduced, this selected video signal is signal-processed using
the control data for the video signal displayed in the small window
area A, then the selected video signal is stored in the memory 718.
Then, the signal is read out from the memory 718, and thus the
monitor output is obtained. In this case, reading from the memory
718 is done so that the reproducing signal may be displayed in the
area denoted by B in FIG. 13. Display on the monitor 703 is done
such that the video signal used to obtain the control data is
displayed in the small window area A, and the video signal which is
WB-controlled by suing the control data obtained from the video
signal displayed in the small area is displayed in the area B.
[0146] When another video signal is further newly selected to be
reproduced, the selected video signal is displayed in the area B.
When another different video signal is designated as the signal
used to obtain the control data, this newly designated video signal
is displayed in the small window area A instead of the previous
one, and the control data is also replaced with the new control
data obtained from this new video signal.
[0147] In each of the above embodiments, WB control is performed by
using the integrated value of the color difference signals.
However, WB control method is not limited to that. It may also be
performed by using R, G, B signals.
[0148] The recording medium for recording the video signals is not
limited to a hard disk, however, another medium such as a memory
card, a magnetic sheet, a magnetic tape, and an optical disk may
also be used.
[0149] In accordance with the second embodiment of the invention,
as described above, WB control in reproduction of a video signal is
performed by using control data obtained from a reference video
signal designated when the video signal is recorded. Thus, an image
of an object even having a large magnitude of color-difference
components may be reproduced with good WB control under the same
color temperature, by designating the video signal as the reference
video signal which is obtained by taking a picture of an object
having a small magnitude of color difference such as a white
object. In this way, high accuracy WB control is possible in
reproduction and even an object having a large magnitude of color
difference components may be reproduced without any loss of
vividness in color.
[0150] In the arrangement according to the third embodiment of the
invention, as described above, when video signals recorded on a
recording medium are reproduced, an arbitrary video signal may be
designated as a reference video signal to obtain WB control data.
As a result of this, even video signals for which high accuracy WB
control would be impossible by themselves may be reproduced with
good enough WB control. In particular, if a picture of a colorless
object such as white paper is taken with illumination of the same
light source as that with which pictures of usual objects are
taken, ideal WB control is possible in reproduction-processing of
these usual objects by designating the above video signal of white
paper as the reference video signal.
[0151] In the arrangement according to the fifth embodiment, a
reference video signal and other video signals are displayed in
multiple window areas, thus it is possible to make quick retrieval
or checking on video signals which are obtained by taking their
pictures under similar conditions.
[0152] Now, a sixth embodiment in accordance with the present
invention will be described hereinbelow.
[0153] In automatic WB control method according to the first
embodiment described earlier, when a picture is taken of a distant
object with a lens having a large focal length, there may be
difference in light source between the location of a camera and the
location of the object. In such a case, in the arrangement with the
external sensor described above, because the color of light in the
outside is measure at the location of the camera, WB correction on
the object is impossible. On the other hand, in the TTL method
described earlier, the color of the object itself leads to large
influence. For example, in some cases where an enlarged picture is
taken of a monochromatic object with a lens having a large focal
length, the color correction is performed on the color of the
object itself and no WB correction occurs on the object.
[0154] With the imaging apparatus according to this embodiment,
wrong automatic WB correction can be avoided even in the case of
the long focal length, which will be described in more detail
hereinbelow.
[0155] In this embodiment, an electronic still camera will also be
taken as an example to which the present invention is adapted. The
circuit configuration shown in FIG. 1 is used in the embodiment.
With reference to the flow chart shown in FIG. 14, WB control in
accordance with this embodiment will be described next.
[0156] First, in step S141, decision is made whether a switch SW1
(14) is on, and if the conclusion is positive, the routine proceeds
to step S142 in which the color is measured with a color sensor 24.
Further, in step S143, decision is made whether a switch SW2 (15)
is on, and if the conclusion is positive, the routine proceeds to
step S144, and if the conclusion is negative, the routine returns
to step S141. In step S144, the focal length of the camera lens 1
is locked and this focal length is read with a system controller
11, and then the routine proceeds to step S145.
[0157] In step S145, depending on the focal length obtained in step
S144, the system controller 11 modifies the color data obtained in
step S142, and then the routine proceeds to step S146. In step
S146, the system controller 11 controls a memory controller 9 so as
to perform WB correction on the taken image with an image processor
27. Finally, an actual picture is taken.
[0158] In arrangement with the external sensor, when the measured
value with the color sensor 24 is near to the daylight color, the
color data is not modified even if the focal length changes, and in
other cases, the color data is limited or modified depending on the
change in focal length. In the TTL method, when the measured color
value is near to that of color of light source such as daylight, a
lamp, and a fluorescent lamp, the color data is not modified
regardless of the change in the focal length, and in other cases,
the color data is limited or modified depending on the change in
the focal length. In the case of hybrid method, the color measured
with the color sensor 24 is compared with the color measured with
TT1. When both measured values are similar to each other, the color
data is not modified even if the focal length changes, and in other
cases, the color data is limited or modified depending on the
change in the focal length.
[0159] In the arrangement in accordance with this embodiment, the
color data is modified depending on the focal length of the camera
lens so as to avoid the wrong WB correction occurring in particular
when the focal length is large. Thus, good WB is always achieved in
reproduction of pictures.
[0160] A seventh embodiment in accordance with the present
invention will be described hereinbelow.
[0161] In addition to the problems described above in the
arrangement with the external sensor or TT1, there are possible
problems as described below.
[0162] In the external WB method, the accuracy of WB control is
influenced by the ambient colors and also by the fact that the
direction of the light source illuminating an object is not always
constant. As a result, the perfect WB reproduction is
impossible.
[0163] In the TTL method, when a picture is taken in a situation
where the color temperature of the light source changes quickly
with time as in the case a picture is taken in the natural light in
the morning or evening, WB control data obtained by taking a
picture of a reference reflection board may be different from that
which would be obtained at the real time when an actual still
picture is taken, and thus there may exist large errors in WB
control in which the error may increase with time.
[0164] There will be described hereinbelow an imaging apparatus
according to this embodiment, which provides a solution to the
above problems.
[0165] FIG. 15 is a block diagram showing a configuration of an
electronic still camera in accordance with this embodiment. In FIG.
15, there are shown a camera lens 151, an image sensor 152 such as
a CCD, an A/D converter 153 for converting the output signals
provided from each pixel of the image sensor 152 into a digital
signal, an RGB processing circuit 155 for processing the digital
pixel data from the output of the A/D converter 153 so as to obtain
RGB digital data, a recording medium 156 for recording the RGB
digital data from the output of RGB processing circuit 155, and a
dating circuit 157 for providing time data representing a date and
time.
[0166] FIG. 16 shows a color filter arranged in front of the image
sensor 152. As shown, this filter comprises Mg (magenta), G
(green), Cy (cyan), and Ye (yellow) disposed for each pixel in
additive complementary color arrangement.
[0167] The operation will be described next.
[0168] Before an actual still picture is taken, a picture of a
neutral gray reference reflection board is taken and this image is
recorded on the recording medium 156 as WB control data together
with the time data given from the dating circuit 157. In a case
where a plurality of pictures are taken with illumination from the
same light source (such as studio illumination and flash lamp)
under the same condition, the above WB control data may be used in
reproduction for all of these still pictures. In this case, the
time data may be used to determine which WB control data should be
used.
[0169] On the other hand, in a case where the condition of the
light source changes quickly with time (as in the case a picture is
taken in the natural light in the morning or evening), after the
last still picture is taken, a picture of the reference reflection
board is taken again to produce the WB control data and the WB
control data is recorded together with the time data.
[0170] FIG. 17 shows WB control data in a 2-dimensional fashion
wherein the levels of R (red) and B (blue) are represented by
horizontal and vertical axes, respectively. In FIG. 17, the color
temperature goes down to the right and down, and goes up to the
left and up.
[0171] As an example, let us take the case where the color
temperature of the light source decreases with time as in the
evening. In FIG. 17, "WB1" denotes the WB control data which was
obtained by taking a picture of the reference reflection board
before actual pictures were taken. "WB2" denotes the WB control
data which was obtained by taking a picture of the reference
reflection board at the time the color temperature decreased after
actual pictures were taken. The still pictures which were taken
between two measurements of the WB control data exist between "WB1"
and "WB2" in FIG. 17.
[0172] When the pictures are reproduced, the WB control data WB1
and WB2 are determined judging from the time data, and points
between two WB1 and WB2 are selected by proper computation. Then,
these selected points are used as the WB control data so as to
achieve better WB control. On the hand, when it is desired to
preserve the effect of the "bright colors of the sunset" and to
shift the colors toward the amber-based colors, similar processing
is performed between WB2 and WB0 which is on the extension of the
segment of the line with WB1 and WB2 so as to achieve the above
purposed.
[0173] To obtain the WB control data, it is not necessary to use
all pixel data comprising a full size picture. Instead, for
example, it may be good enough to record just data associated with
8.times.8 pixels in a central part of a picture for this purpose.
Alternatively, the average value of R and B data corresponding to
about 10 pixels in a central part of a picture may be used to
achieve this purpose.
[0174] In each case, management on the WB control data may be done
by using ID data such as a frame number instead of the time data.
In this case, the dating circuit 157 is not required. It should be
understood that the frame number or other similar data is also
herein denoted by the term "time data".
[0175] In the embodiments described above, it has been assumed that
the image sensor 152 is provided with color filters disposed in the
additive complementary color arrangement and there is provided the
RGB processing circuit 155. However, the average values of Ye, Cy,
and G data in a central part of a picture may be directly recorded
as WB control data preserving additive complementary colors. Then,
when the picture is reproduced, the R and B values may be
calculated from these data as follows: R.dbd.Ye-G, B.dbd.Cy-G. (It
should be noted that the above equations do not include
coefficients.) In this case, the circuit may be configured as shown
in FIG. 18, wherein a switch 160 (multiplexer) is provided for
switching the signals.
[0176] When the image sensor 152 uses the color filters arranged
with RGB primary colors as shown in FIG. 19, the RGB processing
circuit 155 is not required both in taking a picture and in
obtaining WB control data. In this case, the circuit may be
configured as shown in FIG. 20.
[0177] With the arrangement in accordance with this embodiment, the
WB control data is detected and recorded together with the time
data. Furthermore, when the WB control data is required to be
detected in reproduction, the still picture is identified by using
the time data, and the WB adjustment can be accurately performed by
using the corresponding WB control data.
[0178] Moreover, in another aspect of this embodiment, the WB
control data are detected before and after taking pictures, and the
obtained WB control data are recorded together with the time data.
These two WB control data can be used to perform proper WB
adjustment for a plurality of the still pictures which were taken
with illumination of a light source changing with the time between
these WB control data.
* * * * *