|
Digital Camera Patent Abstract
A digital camera including an imaging device, which is adapted to
store electric charges for each spectral color of a plurality of
spectral colors from an object image and output image signals corresponding
to the object image, is provided. The digital camera further includes
a storage time controlling system, which is adapted to control length
of storage time of the electric charges for each spectral color
independently.
Digital Camera Patent Claims
1. A digital camera comprising: an imaging device, which is adapted
to store electric charges for each color component of a plurality
of color components from an object image and outputs image signals
corresponding to the object image; and a storage time controlling
system, which is adapted to control length of storage time of the
electric charges for each color component independently.
2. The digital camera according to claim 1, wherein the plurality
of color components are three primary colors of light.
3. The digital camera according to claim 2, wherein the imaging
device includes a plurality of imaging elements, each of which is
adapted to receive each color component respectively, and the storage
time controlling system is adapted to control the length of the
storage time of the electric charges for each of the imaging elements.
4. The digital camera according to claim 3, wherein the imaging
device is a triple panel imaging device, which includes an optical
system to resolve the object image into the plurality of color components,
and three imaging elements, each of which is adapted to receive
each color component of the resolved plurality of color components.
5. The digital camera according to claim 4, wherein the imaging
element is a charge coupled device.
6. The digital camera according to claim 2, wherein the imaging
device includes a plurality of photo receiving cells, each of which
includes a photo receiving element and a switching element, each
of the photo receiving cells receives each color component, and
the length of the storage time of the electric charges for each
color component is controlled independently by the storage time
controlling system.
7. The digital camera according to claim 6, wherein the photo receiving
cell is a metal-oxide semiconductor.
8. The digital camera according to claim 7, wherein the imaging
device includes a vertical driving system, which is adapted to select
and drive the photo receiving cells that are assigned to each color
component, and a horizontal driving system, which is adapted to
obtain the imaging signals corresponding to each color component.
9. The digital camera according to claim 2, comprising a sensor,
which is adapted to evaluate a color temperature of an external
light, wherein the storage time controlling system is adapted to
control the length of the storage time of the electric charges for
each color component based on the color temperature evaluated by
the sensor.
10. The digital camera according to claim 2, wherein the storage
time controlling system is adapted to control the length of the
storage time of the electric charges for each color component to
be a predetermined length of storage time corresponding to each
of a plurality of light sources with different color temperatures.
11. The digital camera according to claim 2, comprising at least
one of a first operating member, which is adapted to specify a color
component to be adjusted, wherein the storage time controlling system
is adapted to control the length of the storage time of the electric
charges for the color component specified by the first operating
member.
12. The digital camera according to claim 11, comprising a second
operating member, which is adapted to set the length of the storage
time of the electric charges when the color component to be adjusted
is specified by the first operating member.
13. A digital camera comprising: an imaging device, which is adapted
to store electric charges for each color component of a plurality
of color components from an object image and outputs image signals
corresponding to the object image; and a storage time controlling
system, which is adapted to arbitrarily control length of storage
time of the electric charges for each of the plurality of color
components independently based on operations from a user.
14. The digital camera according to claim 13, wherein the plurality
of color components are three primary colors of light.
15. The digital camera according to claim 14, wherein the imaging
device includes a plurality of imaging elements, each of which is
adapted to receive each color component respectively, and the storage
time controlling system is adapted to control the length of the
storage time of the electric charges for each of the imaging elements.
16. The digital camera according to claim 15, wherein the imaging
device is a triple panel imaging device, which includes an optical
system to resolve the object image into the plurality of color components,
and three imaging elements, each of which is adapted to receive
each color component of the resolved plurality of color components.
17. The digital camera according to claim 16, wherein the imaging
element is a charge coupled device.
18. The digital camera according to claim 14, wherein the imaging
device includes a plurality of photo receiving cells, each of which
includes a photo receiving element and a switching element, each
of the photo receiving cells receives each color component, and
the length of the storage time of the electric charges for each
color component is controlled independently by the storage time
controlling system.
19. The digital camera according to claim 18, wherein the photo
receiving cell is a metal-oxide semiconductor.
20. The digital camera according to claim 19, wherein the imaging
device includes a vertical driving system, which is adapted to select
and drive the photo receiving cells that are assigned to each color
component, and a horizontal driving system, which is adapted to
obtain the imaging signals corresponding to each color component.
21. The digital camera according to claim 14, comprising at least
one of a first operating member, which is adapted to be operated
by the user and to specify a color component to be adjusted, wherein
the storage time controlling system is adapted to control the length
of the storage time of the electric charges for the color component
specified by the first operating member.
22. The digital camera according to claim 21, comprising a second
operating member, which is adapted to be operated by the user and
to set the length of the storage time of the electric charges when
the color component to be adjusted is specified by the first operating
member.
23. A digital camera comprising: a sensor, which is adapted to
obtain a color temperature of an external light, an imaging device,
which is adapted to store electric charges for each color component
of a plurality of color components from an object image and outputs
image signals corresponding to the object image; and a storage time
controlling system, which is adapted to control length of storage
time of the electric charges for each of the plurality of color
components independently based on the color temperature of the object
image obtained from the sensor so that a white balance of the object
image is controlled.
24. The digital camera according to claim 23, wherein the plurality
of color components are three primary colors of light.
25. The digital camera according to claim 24, wherein the imaging
device includes a plurality of imaging elements, each of which is
adapted to receive each color component respectively, and the storage
time controlling system is adapted to control the length of the
storage time of the electric charges for each of the imaging elements.
26. The digital camera according to claim 25, wherein the imaging
device is a triple panel imaging device, which includes an optical
system to resolve the object image into the plurality of color components,
and three imaging elements, each of which is adapted to receive
each color component of the resolved plurality of color components.
27. The digital camera according to claim 26, wherein the imaging
element is a charge coupled device.
28. The digital camera according to claim 24, wherein the imaging
device includes a plurality of photo receiving cells, each of which
includes a photo receiving element and a switching element, each
of the photo receiving cells receives each color component, and
the length of the storage time of the electric charges for each
color component is controlled independently by the storage time
controlling system.
29. The digital camera according to claim 28, wherein the photo
receiving cell is a metal-oxide semiconductor.
30. The digital camera according to claim 29, wherein the imaging
device includes a vertical driving system, which is adapted to select
and drive the photo receiving cells that are assigned to each color
component, and a horizontal driving system, which is adapted to
obtain the imaging signals corresponding to each color component.
31. The digital camera according to claim 24, wherein the storage
time controlling system is adapted to control the length of the
storage time of the electric charges for each color component to
be a predetermined length of storage time corresponding to each
of a plurality of light sources with different color temperatures.
32. A method for a using digital camera having an imaging device,
which is adapted to store electric charges for each color component
of a plurality of color components from an object image and output
image signals corresponding to the object image, to control length
of storage time of the electric charges for each color component
independently.
33. A program product comprising instructions to use a digital
camera having an imaging device, which is adapted to store electric
charges for each color component of a plurality of color components
from an object image and output image signals corresponding to the
object image, to control length of storage time of the electric
charges for each color component independently.
Digital Camera Patent Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a digital camera capable
of executing a color photographing, and particularly to such a digital
camera having a white balance adjusting function.
[0002] In digital cameras, a color of a captured image may appear
different from an original color of the object depending on a type
of a light source. For example, a color of a white object photographed
under the sun light is different from a color of the object under
fluorescent lamp light. Generally, the latter is slightly greener
than the former.
[0003] In order to avoid the color difference due to a difference
of the light source type, a digital camera is typically provided
with a white balance sensor. With the white balance sensor, a color
of the object, i.e., a color temperature of the object is measured
by a color meter, and corresponding to the thus measured color temperature,
the color image signal obtained from an image capturing element
is processed to adjust the color of the image so that a white object
can be captured as a white image. An example of such technique is
disclosed in Japanese Patent Provisional Publication No. P2004-193715A.
Depending on whether a strobe emits light or not, the white balance
is adjusted so that the image of the object shows the object with
appropriate colors.
[0004] When white balance is adjusted in such digital cameras,
gain that is applied to each color component (i.e., RGB: red, green,
and blue) obtained from an imaging element is modified. In this
technique, however, some of the gain to the color components are
required to be increased depending on light sources, and according
to the gained values, noise to the color signals may also increase,
which may deteriorate the total quality of the image.
[0005] In such digital cameras, users are generally allowed to
arbitrarily adjust exposure, however, the users are not allowed
to arbitrarily adjust the gain for the RGB colors, and the users
are allowed to apply a preset white balance to the object image,
but not allowed to adjust the white balance arbitrarily. Therefore,
images appealing in desired colors may not be obtained. For images
that appear in the desired colors, the users are required to modify
attributes of color components by using a program, for example photo
retouching software, on devices such as personal computers after
the image is photographed.
SUMMARY OF THE INVENTION
[0006] Aspects of the present invention are advantageous in that
a digital camera capable of imaging an object with appropriate white
balances is provided. Other aspects of the present invention are
advantageous in that a digital camera capable of allowing a user
to arbitrarily adjust white balances to obtain an image in desired
colors is provided.
[0007] According to some aspects of the present invention, a digital
camera including an imaging device, which is adapted to store electric
charges for each color component of a plurality of color components
from an object image and outputs image signals corresponding to
the object image is provided. The digital camera further includes
a storage time controlling system, which is adapted to control length
of storage time of the electric charges for each color component
independently.
[0008] Optionally, the plurality of color components may be three
primary colors of light.
[0009] Optionally, the imaging device may include a plurality of
imaging elements. Each of the imaging elements may be adapted to
receive each color component respectively. The storage time controlling
system may be adapted to control the length of the storage time
of the electric charges for each of the imaging elements.
[0010] Optionally, the imaging device may be a triple panel imaging
device, which includes an optical system to resolve the object image
into the plurality of color components. Each of the three imaging
elements may be adapted to receive each color component of the resolved
plurality of color components.
[0011] Optionally, the imaging element may be a charge coupled
device.
[0012] Optionally, the imaging device may include a plurality of
photo receiving cells. Each of the photo receiving cells may include
a photo receiving element and a switching element. Each of the photo
receiving cells receives each color component. The length of the
storage time of the electric charges for each color component is
controlled independently by the storage time controlling system.
[0013] Optionally, the photo receiving cell may be a metal-oxide
semiconductor.
[0014] Optionally, the imaging device may include a vertical driving
system, which is adapted to select and drive the photo receiving
cells that are assigned to each color component. The imaging device
may further include a horizontal driving system, which is adapted
to obtain the imaging signals corresponding to each color component.
[0015] Optionally, the digital camera may include a sensor, which
is adapted to evaluate a color temperature of an external light.
The storage time controlling system may be adapted to control the
length of the storage time of the electric charges for each color
component based on the color temperature evaluated by the sensor.
[0016] Optionally, the storage time controlling system may be adapted
to control the length of the storage time of the electric charges
for each color component to be a predetermined length of storage
time corresponding to each of a plurality of light sources with
different color temperatures.
[0017] Optionally, the digital camera may include at least one
of a first operating member, which is adapted to specify a color
component to be adjusted. The storage time controlling system may
be adapted to control the length of the storage time of the electric
charges for the color component specified by the first operating
member.
[0018] Optionally, the digital camera may include a second operating
member, which is adapted to set the length of the storage time of
the electric charges when the color component to be adjusted is
specified by the first operating member.
[0019] According to some aspects of the present invention, a digital
camera including an imaging device, which is adapted to store electric
charges for each color component of a plurality of color components
from an object image and outputs image signals corresponding to
the object image, is provided. The digital camera further includes
a storage time controlling system, which is adapted to arbitrarily
control length of storage time of the electric charges for each
of the plurality of color components independently based on operations
from a user.
[0020] Optionally, the digital camera may have at least one of
a first operating member, which is adapted to be operated by the
user and to specify a color component to be adjusted. The storage
time controlling system may be adapted to control the length of
the storage time of the electric charges for the color component
specified by the first operating member.
[0021] Optionally, the digital camera may have a second operating
member, which is adapted to be operated by the user and to set the
length of the storage time of the electric charges when the color
component to be adjusted is specified by the first operating member.
[0022] According to some aspects of the present invention, a digital
camera including a sensor, which is adapted to obtain a color temperature
of an external light, is provided. The digital camera further includes
an imaging device, which is adapted to store electric charges for
each color component of a plurality of color components from an
object image and outputs image signals corresponding to the object
image. The digital camera further includes a storage time controlling
system, which is adapted to control length of storage time of the
electric charges for each of the plurality of color components independently
based on the color temperature of the object image obtained from
the sensor so that a white balance of the object image is controlled.
[0023] According to some aspects of the present invention, a method
for using a digital camera having an imaging device is provided.
The digital camera is adapted to store electric charges for each
color component of a plurality of color components from an object
image and output image signals corresponding to the object image,
to control length of storage time of the electric charges for each
color component independently.
[0024] According to some aspects of the present invention, a program
product having instructions to use a digital camera including an
imaging device is provided. The digital camera is adapted to store
electric charges for each color component of a plurality of color
components from an object image and output image signals corresponding
to the object image, to control length of storage time of the electric
charges for each color component independently.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0025] FIG. 1 is a perspective view showing a front appearance
of a digital camera according to a first embodiment of the present
invention.
[0026] FIG. 2 is a perspective view showing a rear appearance of
the digital camera according to an embodiment of the present invention.
[0027] FIG. 3 is a block diagram illustrating an electrical configuration
of the digital camera according to the embodiment of the invention.
[0028] FIG. 4 is a diagram illustrating a configuration of an imaging
device of the digital camera according to the embodiment of the
invention.
[0029] FIG. 5 is a flowchart illustrating an automatic white balance
adjusting operation of the digital camera according to the embodiment
of the invention.
[0030] FIG. 6 is a flowchart illustrating a preset white balance
adjusting operation of the digital camera according to the embodiment
of the invention.
[0031] FIG. 7 is a flowchart illustrating a manual white balance
adjusting operation of the digital camera according to the embodiment
of the invention.
[0032] FIG. 8 shows an example of a histogram shown on an LCD (liquid
crystal display) of the digital camera according to the embodiment
of the invention.
[0033] FIG. 9 is a block diagram illustrating an electrical configuration
of the digital camera according to a second embodiment of the invention.
[0034] FIG. 10 is a diagram illustrating a circuitry of an imaging
device of the digital camera according to the embodiment of the
invention.
DETAILED DESCRIPTION OF THE EMBODIMENT
[0035] Referring to the accompanying drawings, a digital camera
according to an embodiment of the invention will be described in
detail.
First Embodiment
[0036] FIG. 1 is a perspective view showing a front appearance
of a digital camera according to a first embodiment of the present
invention. The digital camera 1000 is a digital SLR (single-lens
reflex) camera having interchangeable lenses. On a front surface
of the camera body 1 are provided with a lens mount 2, to which
a photographing lens (not shown) is attached, and a white balance
sensor 3, which is for receiving external light to evaluate color
temperature. On a top surface of the camera body 1, a main switch
4 of a rotary lever, and a shutter button 5 to be pressed for releasing,
an information LCD 6 for monitoring various information, and a mode
dial 7 for setting various photographing modes are arranged. The
shutter button 6 also functions as a photometry switch. In the vicinity
of the shutter button 5 is arranged a front dial 8, which is rotated
for adjusting exposure. Also on the top surface of the camera body
1, RGB adjust buttons 9R, 9G, and 9B for each RGB color.
[0037] FIG. 2 is a perspective view showing a rear appearance of
the digital camera according to an embodiment of the present invention.
On a rear surface of the camera body 1 is provided with a main LCD
10 for displaying images captured and various information. Further,
a plurality of mode buttons 11, an exposure adjust button 12, an
AE (automatic exposure) lock button 13, a rear dial 14, and a finder
15 are provided. The mode buttons 11 are for various settings, and
the exposure adjust button 12 is pressed for adjusting exposure.
The AE lock button 13 is pressed for locking exposure. The rear
dial 14 is rotated for adjusting each exposure of the RGB colors.
[0038] FIG. 3 is a block diagram illustrating an electrical configuration
of the digital camera according to the embodiment of the invention.
An image of an object formed through the photographing lens 16,
which is attached to the lens mount 2, is passed through a diaphragm
101 and reflected in a movable half mirror 102, then formed on a
focusing lens 103. The image formed on the focusing lens 103 is
further reflected in a pentaprism 104 and can be observed through
the eyepiece lens 105. The image passed through the movable half
mirror 102 is further reflected by a second mirror 106, and received
in a distance measuring unit 121, which evaluates distance to the
object. The image is then transmitted through a shutter 107, which
opens synchronously to the movable half mirror 102 when the movable
half mirror 102 is uplifted. Finally, the image is received by an
imaging device 20, wherein each of CCD (charge coupled device) element
26, 27, and 28 corresponding to each of the RGB color captures the
image.
[0039] The captured signals for each color are amplified by an
amplifier 111, and converted to digital image signals by an A/D
(analog-to-digital) converter 112. To the digital image signals,
color processing, such as a gamma processing and the like, is applied
in a signal processing circuit 113. The processed image signals
are then compressed by a compressing circuit 114 (or may not be
compressed), and stored in a VRAM (video RAM) 115. A CPU 100 contains
a clock generator 116. Storage time of electric charges in each
CCD element 26, 27, and 28 can be individually set by a CPU 100
controlling R-CCD driver 117, G-CCD driver 118, and B-CCD driver
119 individually through a clock generator 116.
[0040] The CPU 100 uses output of a DC/DC converter 132, which
uses DC/DC converted voltage of a battery 131, as a power source.
When the image is captured, the CPU controls an AF (automatic focusing)
control unit 122, which is provided inside the camera body 1, and
a diaphragm control unit 123, which is provided inside the photographing
lens 16. The CPU 100 further controls a mirror control unit 124
to operate the movable half mirror 102. The distance measuring unit
121 evaluates the distance to the object, and the CPU 100 controls
the shutter control unit 125 to open/shut the shutter 107. The CPU
100 controls the information LCD 6 to display various information
for photographing and the main LCD 10 to display captured images.
The CPU 100 also controls a strobe device controlling unit 134,
which controls the strobe device 133 to emit light.
[0041] The CPU 100 stores color temperature information evaluated
by the white balance sensor 3 and exposure information calculated
by an exposure control unit 109 based on the evaluated value of
a photometer 108, which is arranged in the vicinity of the eyepiece
lens 105, in a ROM equipped to the CPU 100. Further, the CPU 100
stores switch status information of the photometry switch and the
release switch of the shutter button 5. The CPU 100 is also provided
with mode information that is inputted with mode setting members,
for example the mode dial 7 and the mode buttons 11. Furthermore,
the CPU stores information concerning the exposure adjust button
12, when the exposure adjust button 12 is pressed, and information
concerning exposure for each of the RGB colors, when any of the
RGB adjust buttons 9R, 9G, and 9B is pressed. The CPU 100 also stores
information from the front dial 8 and the rear dial 14 when front
dial 8 and the rear dial 14 are rotated.
[0042] The imaging device 20 converts the image of the object through
the photographing lens 16 into digital signals. In the present embodiment,
the imaging device 20 is configured to be a triple-CCD.
[0043] FIG. 4 shows a diagram illustrating a configuration of the
imaging device 20 of the digital camera according to the embodiment
of the invention. On an optical axis of the photographing lens 16
is provided a dichroic prism, which includes three prisms. Each
prism of the three prisms is hereinafter referred to as a B-prism
21, R-prism 22, and G-prism 23, respectively. The B-prism 21, the
R-prism 22, and the G-prism 23 are formed with transparent resin
or glass. The B-prism 21 is coated with B reflective dichroic filter
24 that reflects blue light in a side direction, and the R-prism
22 is coated with R reflective dichroic filter 25 that reflects
red light in another side direction. The G-prism 23 is not provided
with reflective dichroic filter, and green light entered in the
G-prism 23 is transmitted to the back of the G-prism 23. An end
surface of each prism is provided with a CCD element, i.e., an end
surface of the B-prism 21 is provided with a CCD element (hereinafter
referred to as a B-CCD 26), and end an surface of the R-prism 22
is provided with an R-CCD 27, and an end surface of the G-prism
23 is provided with a G-CCD 28.
[0044] As shown in the arrows and the dotted lines in FIG. 4, the
light of the object image is entered through the photographing lens
16, and the blue light is reflected by the reflective dichroic filter
B and received by the B-CCD 26. Similarly, the red light is reflected
by the reflective dichroic filter R and received by the R-CCD 27.
The green light is transmitted through the G-prism 23, and received
by the G-CCD 28. Thus, the light of the object image is resolved
into three colors, which are red, green, and blue, and received
by the respective CCD, and output as digital signals corresponding
to each color.
[0045] Methods to adjust exposure and white balance will be described
below.
[0046] Adjusting exposure is conducted in a known method. That
is, when the exposure adjust button 12 is pressed, the CPU 100 enters
an exposure adjusting mode. In the exposure adjusting mode, when
the front dial 8 is rotated, the CPU 100 drives controlling units,
for example the diaphragm control unit 123 and the shutter control
unit 125, to adjust exposure for amount corresponding to the rotation
of the front dial 8 and controls the light of the object image that
reaches to the imaging device 20. Thus, the amount of electric charges
to be stored in each of the RGB-CCDs 26, 27, and 28 is controlled,
and signal levels to be output from the imaging device 20 is adjusted.
[0047] Adjusting white balance is conducted based on setting of
a white balance mode with the front dial 8 and the mode buttons
11. In this embodiment, automatic white balance mode, preset white
balance mode, and manual white balance mode are provided as the
white balance mode.
[0048] In the automatic white balance mode, the white balance is
adjusted based on the color temperature of a light source that is
evaluated by the white balance sensor 3. The automatic white balance
mode starts when the user specifies the mode by operating the mode
dial 7. In S101, as seen in the flowchart in FIG. 5, the CPU 100
recognizes the white balance mode is the automatic white balance
mode. In S102, the CPU 100 obtains the evaluated color temperature
of the light source from the white balance sensor 3. In S103, the
CPU 100 refers to a reference table, which has been created and
stored in a memory, based on the color temperature. The reference
table contains ratios of storage times for electric charges corresponding
to each color component to be stored in the RGB-CCDs 26, 27, and
28. In S104, the CPU 100 controls the storage time for each of the
RGB-CCDs 26, 27, and 28 individually. In S105, each of the RGB-CCDs
26, 27, and 28 respectively output image signals. With the above
process, the image signals obtained from the R-CCD 27, G-CCD 28,
and B-CCD 26 are processed by some of the units, for example the
signal processing circuit 113, and the output image is represented
to be adjusted to the color temperature of the light source.
[0049] In the preset white balance mode, the white balance is adjusted
based on a setting selected by the user among different preset color
temperature settings depending on color temperatures of light sources,
which are for example a filament lamp, a fluorescent lamp, and the
sun. FIG. 6 is a flowchart illustrating the preset white balance
adjusting operation of the digital camera according to the embodiment
of the invention. In S201, the CPU 100 recognizes the white balance
mode is in the preset white balance mode. In S202, the CPU 100 obtains
the color temperature of the light sources that is specified by
an operation of the user with the front dial 8 and the mode buttons
11. In S203, the CPU 100 refers to the reference table, which has
been created and stored in a memory, for a ratio of storage time
for charges to be stored in each of the RGB-CCDs 26, 27, and 28
based on the color temperature. In S204, the CPU 100 controls the
storage time for each of the RGB-CCDs 26, 27, and 28 individually,
similarly to S104 in the automatic white balance mode. In S205,
each of the RGB-CCDs 26, 27, and 28 respectively output image signals.
With the above process, the output image is represented to be adjusted
to the color temperature of the light source.
[0050] In the manual white balance mode, the white balance is adjusted
manually by the user operating the front dial 8 and the mode buttons
11. FIG. 7 is a flowchart illustrating a manual white balance adjusting
operation of the digital camera according to the embodiment of the
invention. In S301, the CPU 100 recognizes the white balance mode
is in the manual white balance mode. In S302, the CPU 100 obtains
information indicating any of the RGB adjust buttons 9R, 9G, and
9B has been pressed. In S303, the CPU further obtains information
indicating that the rear dial 14 has been rotated. In S304, the
CPU controls the storage time of the CCD that corresponds to the
color specified by the button being pressed for the amount corresponding
to the rotation of the rear dial 14. For another color components,
the CPU repeats S302, S303, and S304. In S305, each of the RGB-CCDs
26, 27, and 28 respectively output image signals. With the above
process, the output image is represented to be in the white balance
adjusted manually.
[0051] When the white balance is adjusted manually, a histogram
window 10a to indicate the spectral distribution of the RGB may
be shown on the main LCD 10. FIG. 8 shows an example of the histogram
overlaid on the main LCD of the digital camera according to the
embodiment of the invention. With this configuration, the user is
allowed to view the histogram of each RGB that corresponds to the
rotation amount of the rear dial 14, and to adjust the white balance
for desired amount. Thus, noise to color signals that is conventionally
increased by increasing gain values can be limited even when the
white balance is manually adjusted.
Second Embodiment
[0052] FIG. 9 is a block diagram illustrating an electrical configuration
of a digital camera according to a second embodiment of the invention.
An appearance of the digital camera in the second embodiment is
similar to the appearance shown in the first embodiment (see FIGS.
1 and 2). In this embodiment, the configuration corresponding to
the configuration of the first embodiment is referred to by the
same reference numbers, and description of those are omitted. In
the second embodiment, an imaging device 20A includes a single MOS
(CMOS: Complementary Metal-Oxide Semiconductor). FIG. 10 is a diagram
illustrating a circuitry of an imaging device of the digital camera
according to the embodiment of the invention. In the MOS, each photo
receiving cell CELL includes a photo diode PD and a vertical transistor
(i.e., a V-MOS) as a switching device to output the electric charges
stored in the photo diode PD, and a plurality of the photo receiving
cells CELL are aligned in matrix. In a photo receiving path of each
photo diode PD is inserted any one of red color filter, green color
filter, and blue color filter (not shown). With these filters, each
photo receiving cell CELL is assigned to receive and capture the
corresponding color of light. In this embodiment, adjoining four
photo receiving cells CELL, which are two green receiving cells
(hereinafter referred to as G-cells), one red receiving cell (hereinafter
referred to as R-cell), and one of blue receiving cell (hereinafter
referred to as B-cell), are configured to be in a unit, and a plurality
of units are aligned in matrix.
[0053] Gates of the V-MOSes are respectively connected to each
of R-vertical shift register 201, G-vertical shift register 202,
and B-vertical shift register 203. The gates are opened and each
of the photo receiving cells corresponding to each color component
are vertically sequentially selected and activated based on vertical
start pulses R-VSP, G-VSP, and B-VSP, which are supplied to each
vertical RGB shift register 201, 202, and 203, in synchronization
to a vertical clock V-CLK. Thus, each photo receiving cell CELL
stores the electric charges generated by the photo diode PD during
a period since the V-MOS is turned off and until the V-MOS is turned
on again. Drains of each V-MOS are respectively connected to outputs
for each color R-OUT, G-OUT, and B-OUT through horizontal transistors
H-MOSes. Gates of the H-MOSes are respectively connected to each
of R-horizontal shift register 204, G-horizontal shift register
205, and B-horizontal shift register 206. The gates are opened and
each of the photo receiving cells corresponding to each color component
are horizontally sequentially selected and activated based on horizontal
start pulses R-HSP, G-HSP, and B-HSP, which are supplied to each
RGB horizontal shift register 204, 205, and 206, in synchronization
to the horizontal clock H-CLK.
[0054] The vertical and horizontal RGB shift registers 201-206
are controlled respectively by R-MOS driver 117A, G-MOS driver 118A,
and B-MOS driver 119A, which are controlled by the clock generated
by the clock generator 116. The CPU 100 controls the RGB-MOS drivers
117A, 118A, and 119A based on the white balance mode set by the
user with the front dial 8 and the mode buttons 11.
[0055] As described above, the timing to activate the V-MOSes of
each RGB receiving cells can be controlled by controlling the RGB
vertical shift registers 201, 202, and 203. Thus, the storage time
for electric charges in the photo diodes PD in each cell can be
controlled. Therefore, when the timing to activate the V-MOSes is
delayed, the storage time of the photo diodes PD becomes longer,
and when the timing to activate the V-MOSes is forwarded, the storage
time becomes shorter. The timing can be adjusted independently for
R, G and B, by each of the RGB shift registers 201, 202, and 203,
therefore, the storage time for the photo receiving cells of one
color does not affect to the storage time of the photo receiving
cells of another colors. Thus, noise to color signals output from
the V-MOSes can be controlled without increasing noise levels.
[0056] It should be noted that, also in the second embodiment,
the white balance can be adjusted following any of the processes
shown in the flowcharts in FIGS. 5-7 based on the mode, which is
one of the automatic white balance mode, the preset white balance
mode, and the manual white balance mode, set by the user, similarly
to the first embodiment. However, it should be noted in the second
embodiment, for controlling the storage time of each image signal
for each RGB color, the storage time of each V-MOS for each RGB
color is independently controlled. Also it should be noted that,
the CCD in FIGS. 5-7 in the first embodiment is respectively replaced
with MOS. With this configuration, the noise to color signals that
is conventionally increased by increasing gain values can be limited
even when the white balance is manually adjusted, and images with
appropriate white balance can be obtained. It should be noted in
the second embodiment that the imaging device includes one imaging
element, thus, it is advantageous to provide a downsized digital
camera and to reduce production cost.
[0057] In the above-described embodiments, the white balance is
adjusted in the manual white balance mode by pressing any one of
the RGB adjust buttons 9R, 9G, and 9B to specify the color components
to be adjusted and simultaneously rotating the rear dial 14. However,
the invention is not limited to such configuration. The color components
to be adjusted may be specified by pressing one exposure adjust
button sequentially to switch from one of the RGB to another. In
this case, one exposure adjust button is required, and three of
the RGB adjust buttons 9R, 9G, and 9B may not be required, therefore,
the number of buttons required for the camera may be reduced. Optionally,
the color components to be adjusted may be specified by operations
to one dial, or by operations based on a display shown on one of
the LCDs. It should be noted the arrangement of the RGB prisms 21,
22, and 23 of the imaging device 20 is not limited to the arrangement
described in the first embodiment. The G-prism 23 may be provided
with a reflective dichroic filter and arranged to the upfront, or
the R-prism 22 may be arranged to the upfront.
[0058] The present disclosure relates to the subject matter contained
in Japanese Patent Application No. 2004-323177, filed on Nov. 8,
2004, which is expressly incorporated herein by reference in its
entirety. |