JPH11168749A - Digital camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital camera that properly reproduces white color, even if color temperature of a light source is changed. SOLUTION: In this digital camera 100, a CCD 103 converts an object light into an electrical signal via a lens unit 101, and provides an output of the electrical signal as a color image signal, an A/D converter 106 executes A/D conversion to the color image signal and provides an output of the converted signal as a digital color image signal, and an IPP 107 provides an output of an auto white balance(AWB) evaluation value, in response to luminance data of each color component RGB of the digital color image signal. A CPU 121 references a proper gain under each lighting condition stored in a flash memory 130, calculates a proper gain corresponding to the AWB evaluation value outputted from the IPP 107 within a set color temperature range and sets the calculated proper gain to a white balance adjustment section for conducting the adjustment of the AWB.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a digital camera, and more particularly, to a digital camera having an AWB function.

[0002]

2. Description of the Related Art In a digital camera, white balance adjustment is required to obtain a high quality color image. If this white balance is lost, not only will the captured image look tinted when shooting a white subject, but also the color reproducibility when shooting a general subject will be degraded, and a high quality reproduced image will be obtained. Disappears.

[0003] When the color temperature of the light source changes, the white balance changes. In each case, a white (or achromatic) subject is photographed, and the three primary color signals R, G, and B, which are the photographing signal outputs of the digital camera, are taken. Must be adjusted so that the output ratio becomes 1: 1: 1. This is white balance adjustment, and this adjustment is generally performed by adjusting a variable gain circuit provided on a transmission line for each color signal.

[0004]

However, the conventional digital camera has a problem that if the color temperature of the light source changes, white cannot be reproduced properly.

[0005] The present invention has been made in view of the above problems, and has as its object to provide a digital camera capable of appropriately reproducing white even when the color temperature of a light source changes.

[0006]

Means for Solving the Problems The above-mentioned problems are solved,
In order to achieve the object, a digital camera according to claim 1 converts an object light via an optical system into an electric signal and outputs the same as a color image signal, and an A / D conversion of the color image signal. A / D conversion means for outputting as a digital color image signal, white detection range setting means for setting a color temperature range for which white balance is to be adjusted, and respective color components (RGB) of the digital color image signal. AWB (Auto W
AWB evaluating means for outputting an evaluation value of the digital color image signal, AWB adjusting means for adjusting the gain of at least two colors of the digital color image signal, storage means for storing appropriate gain values under a plurality of lighting conditions, and the storage The AWB is referred to within the color temperature range set by the white detection range setting means with reference to the appropriate gain value stored in the means.
AWB control means for calculating an appropriate gain value corresponding to the AWB evaluation value output from the evaluation means and setting the gain of the AWB adjustment means.

Further, a digital camera according to claim 2 is
An image pickup device that converts subject light via an optical system into an electric signal and outputs the signal as a color image signal, A / D conversion means that A / D converts the color image signal and outputs it as a digital color image signal, A white detection range setting means for setting a color temperature range to be adjusted, and an AWB
A detection luminance range setting unit for setting a luminance range detected by the evaluation unit; and a color component (R) of the digital color image signal within the luminance range set by the detection luminance range setting unit.
AWB (Auto Whi) according to the luminance data of GB
te Balance) AWB evaluation means for outputting an evaluation value, AWB adjustment means for adjusting the gain of at least two colors of the digital color image signal, storage means for storing appropriate gain values under a plurality of lighting conditions, With reference to the appropriate gain value stored in the storage unit, the AW within the color temperature range set by the white detection range setting unit.
AWB control means for calculating an appropriate gain value corresponding to the AWB evaluation value output from the B evaluation means and setting the gain of the AWB adjustment means.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a digital camera according to the present invention will be described below in detail with reference to the accompanying drawings.

[Summary of the Invention] The digital camera according to the present embodiment has an automatic white balance (AWB) adjustment function, and its CPU (AWB control means) has an AWB adjustment value and white extraction setting of the IPP. AWB (Auto White B) output from the circuit (AWB evaluation means)
an appropriate gain value within the set color temperature range is calculated by referring to the appropriate gain value under each lighting condition written in the flash memory (storage means) in the adjustment step based on the evaluation value. , And calculate the appropriate gain as IP
AWB control is performed by setting the white balance adjustment unit (AWB adjustment means) of P. In addition, the digital camera adjustment device calculates a corresponding appropriate gain for each lighting condition based on the AWB evaluation value output from the IPP of the digital camera. This appropriate gain is written to the flash memory of the digital memory. In this specification, the digital camera adjustment system includes the digital camera and the digital camera adjustment device.

Hereinafter, the description will be made in the order of [digital camera], [digital camera adjustment device], and [AWB adjustment].

[Digital Camera] FIG. 1 is a configuration diagram of a digital camera according to the present embodiment. In the figure,
Reference numeral 100 denotes a digital camera. The digital camera 1 includes a lens 101, a mechanical mechanism 102 including an autofocus, a CCD 103, a CDS circuit 104, a variable gain amplifier (AGC amplifier) 105, and an A / D converter 10.
6, IPP107, DCT108, coder 109, M
CC 110, RAM (internal memory) 111, PC card interface 112, CPU 121, display unit 122,
Operation unit 123, motor driver 125, SG (control signal generation) unit 126, strobe 127, battery 12
8, DC-DC converter 129, flash memory 1
30. Also, a PC card 150 that can be detached via the PC card interface 112 is provided.
Is connected.

The lens unit includes a lens 101, a mechanical mechanism 102 including an autofocus (AF), an aperture, and a filter section. A mechanical shutter of the mechanical mechanism 102 performs simultaneous exposure of two fields. A CCD (Charge Coupled Device) 103 converts a video image input via a lens unit into an electric signal (analog image data).
The CDS (correlated double sampling) circuit 104 is a CCD
This is a circuit for reducing noise in the image sensor.

The AGC amplifier 105 corrects the level of the signal that has been correlated double-sampled by the CDS circuit 104. Further, the A / D converter 106 is connected to the AGC amplifier 1
The analog image data input from the CCD 103 via the input device 05 is converted into digital image data. That is, C
The output signal of the CD 103 is supplied to the CDS circuit 104 and the AG
The signal is converted into a digital signal at an optimum sampling frequency (for example, an integer multiple of the subcarrier frequency of the NTSC signal) by the A / D converter 105 via the C amplifier 105.

The digital signal processing unit IPP
(Image Pre-Processor) 107, DCT (Discrete Cos)
ine Transform) 108 and coder (Huffman Enco
A der / Decoder) 109 performs various processing, correction, and data processing for image compression / decompression on the digital image data input from the A / D converter 106 by dividing the digital image data into color difference (Cb, Cr) and luminance (Y). Apply. Image compression / decompression unit 107
Performs, for example, orthogonal transformation, which is a process of JPEG-compliant image compression / decompression, and Huffman encoding / decoding, which is a process of JPEG-compliant image compression / decompression.

Further, an MCC (Memory Card Controlle)
An r) 110 temporarily stores the compressed image and records the image on the PC card 150 via the PC card interface 112 or reads the image from the PC card 150.

The CPU 121 uses a RAM (not shown) as a work area in accordance with a program stored in a ROM (not shown), and in accordance with an instruction from the operation unit 123 or an external operation instruction such as a remote controller (not shown). Controls all operations inside the camera. Specifically, the CPU 1
Reference numeral 21 controls an imaging operation, an automatic exposure (AE) operation, an automatic white balance (AWB) adjustment operation, an AF operation, and the like. The CPU 121 turns ON / OF the AE function, the AWB function, and the AF function in response to a command transmitted from the computer 207 of the digital camera adjustment device 200.
F can be set. The camera power is input to a DC-DC converter 129 from a battery 128, for example, a NiCd, nickel metal hydride, lithium battery, or the like.
It is supplied inside the digital camera.

The display unit 122 is implemented by an LCD, an LED, an EL, etc., and displays photographed digital image data and decompressed recorded image data. The mode display unit displays the status of the digital camera. Is displayed on the screen. In addition, the operation unit 123 is used to select a function, a shooting instruction,
And buttons for externally setting various other settings. In the flash memory 130, an appropriate gain value under each lighting condition for performing AWB adjustment is written.

The digital camera 100 includes a recording mode for recording image data obtained by capturing an image of a subject on a PC card 150, a display mode for displaying an image recorded on the PC card 150, and a digital camera adjustment device 2.
A recording / adjustment mode for writing adjustment data to the flash memory 130 in cooperation with 00 is provided.

FIG. 2 is a diagram showing an example of a specific configuration of the IPP 107. As shown in FIG. 2, the IPP 107 separates the digital image data input from the A / D converter 106 into R, G, and B color components.
A signal interpolating unit 1072 for interpolating the separated R, G, B image data, a pedestal adjusting unit 1073 for adjusting the black level of each of the R, G, B image data, and each of the R, B images A white balance adjustment unit 1074 for adjusting the white level of the data; a digital gain adjustment unit 1075 for correcting each of the R, G, and B image data with a gain set by the CPU 121; a gamma conversion unit 1076 for performing γ conversion, a matrix unit 1077 for separating RGB image data into color difference signals (Cb, Cr) and a luminance signal (Y), a color difference signal (Cb, Cr), and a luminance signal (Y) And a video signal processing unit 1078 that creates a video signal based on the video signal and outputs the video signal to the display unit 122.

The IPP 107 further includes a Y operation unit 1079 for detecting the luminance data (Y) of each of the R, G, and B image data after the pedestal adjustment by the pedestal adjustment unit 1073.
A BPF 1080 that passes only a predetermined frequency component of the luminance data (Y) detected by the Y operation unit 1079,
An AF evaluation value circuit 1081 that outputs a digital count value corresponding to the luminance data (Y) that has passed through F1080 to the CPU 121 as an AF evaluation value, and a digital count value corresponding to the luminance data (Y) detected by the Y operation unit 1079. A
An AE evaluation value circuit 1082 that outputs to the CPU 121 as an E evaluation value; a Y operation unit 1083 that detects luminance data (Y) of each of R, G, and B image data after gain adjustment by the digital gain adjustment unit 1075; A digital count value corresponding to the luminance data (Y) detected by the Y operation unit 1083 within the luminance range obtained (within the white detection area) is represented by A
An AWB evaluation value / white extraction setting circuit 1084 that outputs to the CPU 121 as a WB evaluation value; a CPU I / F 1085 that is an interface with the CPU 121;
DCTI / F108 which is the interface with
6 and so on.

The above-mentioned white balance adjustment unit 1074
Has multipliers 1074r and 1074b for each of R and B, and R input to each of the multipliers 1074r and 1074b.
R, B set by the CPU 121 to the image data of B
Are multiplied by the respective gain data to adjust the white balance of the image data. The luminance range (white detection area) of the AWB evaluation value / white extraction setting circuit 1084 is C
This is set by the PU 121.

The above-mentioned digital gain adjustment unit 1075
Are the multipliers 1075r, 1075g, 10
75b, and each of the multipliers 1075r, 1075
g, 1075b to the R, G, B image data
The CPU 121 multiplies each of the RGB gain data set by the CPU 121 to adjust the signal level of the RGB image data.

Next, an operation related to AWB control in the digital camera 100 will be described.

The CPU 121 sets the appropriate gain corresponding to the AWB evaluation value fetched from the IPP 107 and stored in the RAM within the color temperature range (white detection area) for which the set white balance is to be adjusted.
The calculation is performed with reference to the appropriate gain under each lighting condition stored in 30. Subsequently, the CPU 121 applies the calculated appropriate gain to the R and B multiplier 1074 of the white balance adjustment unit 1074 for the image data captured and captured.
r and 1074b are respectively multiplied to adjust the signal level of image data to perform AWB control.

Prior to the normal photographing operation, the AWB evaluation value is stored in a (pre-scan) RAM, and the AWB control is performed based on the AWB evaluation value during photographing. Any method may be used in which the AWB evaluation value is fetched in the photographing operation and stored in the RAM, and AWB control is performed at the next photographing based on the fetched AWB evaluation value.

Although the gains adjusted by the white balance adjustment unit 1074 are R and B, the present invention is not limited to this, and the gain of at least two or more combinations of R, G and B is adjusted. May be.

[Digital Camera Adjustment Apparatus] FIG. 3 is a diagram showing an external configuration of a digital camera adjustment apparatus 200 according to the present embodiment. FIG. FIG. 2 is a diagram showing a block configuration of a camera adjustment system 300.

The digital camera adjustment device 200 shown in FIGS. 3 and 4 includes a digital camera supply power supply 201 for supplying power to the digital camera 100 and an adapter 20 for GPIB control of the digital camera supply power supply 201.
2, a monitor 203 for displaying an image captured by the digital camera 100, a vector scope 204 for displaying the amplitude and phase of a color signal (RGB) scanned by the digital camera 100 in a vector form, and a monitor 203 for video signal observation. Waveform monitor 205, transmission type gray scale light source 206, digital camera 10
0, a computer 207 for controlling the above-mentioned measuring instruments (such as the vector scope 204 and the wave form monitor 205), a display 208 for displaying an adjustment menu and the like as a display device of the computer 207, and a GPIBI mounted on the computer 207 main body. / F209,
An adjustment jig main body 210 for fixing the digital camera 100 and connecting signals such as a power supply 201 for digital camera supply, RS-232C, VIDEO, etc., and a filter (W4, C10,
C4, W16, etc.) filter switching device 212 for switching
And a filter (W4, C1) of the filter switching device 212.
0, C4, W16, etc.) in accordance with a command from the computer 207. The light source 206 and the filter switching device 212 implement an illumination unit.

FIG. 5 is a diagram showing the configuration of the computer 207. As shown in FIG. 5, the computer 207 includes an input unit 2071 for giving an operation instruction, a CPU 2072 for controlling the entire computer device, and the CPU 2
RO that stores various control programs for operating 072
M2073 and a RAM 2074 used as a work area of the CPU 2072. The control program includes, for example, an adjustment data creation program for writing adjustment data such as appropriate gain data under each lighting condition into the flash memory 130 of the digital camera 100.

[AWB Adjustment] Next, the digital camera 10
The processing procedure of the AWB adjustment executed in cooperation with the digital camera adjustment apparatus 200 will be described with reference to a flowchart shown in FIG. FIG. 6 is a flowchart showing the procedure of AWB adjustment.

In this AWB adjustment, the light source 20
6 (5100K) is set, and the filter switching device 212 switches filters (W4, C10, C4, W16, etc.) having different characteristics, thereby changing the illumination conditions of the light source 206 and changing the AWB adjustment data. Is calculated.

First, as shown in FIG. 5, the digital camera 100 is connected to the jig main body 2 of the digital camera adjustment device 200.
When the digital camera 100 and the digital camera adjustment device 200 are powered on, the digital camera 100 and the digital camera adjustment device 200 are initialized (steps S1 and P1).
At 08, a display menu as shown in FIG. 7 is displayed on the display 208 (step S2). In the digital camera 100, the adjustment / recording mode is set (Step P2).

Then, in the digital camera adjustment device 200, when the AWB adjustment is selected from the display menu screen (see FIG. 7) of the display 208 (step S).
3), a filter selection screen as shown in FIG. 8 is displayed,
A filter is selected from this selection screen (step S4). Then, the CPU 2072 of the computer 207
Switches the filter of the light source 206 to the selected filter via the control box 211 (step S5).

Subsequently, the CPU 2 of the computer 207
072 is a command indicating the start of AWB adjustment,
The CP of the digital camera 100 is connected via a 32C cable.
It transmits to U121 (step S6). Then, the value of the counter K is set to the initial value "0" (step S7).

Upon receiving this command (step P3), the CPU 121 of the digital camera 100
With the function and the AE function turned on and the AWB function turned off, the multipliers 1074r and 1074b of the white balance adjustment circuit 1074 provide R and B respectively.
The initial value of the gain is set and shooting is performed (step P
4).

At the time of this photographing, the AWB evaluation value circuit 1084 of the IPP 107 outputs the R, G, and B AWB evaluation values within the set luminance range (white detection area) to the CP.
Output to U121. The CPU 121 sets these R,
The AWB evaluation values of G and B are converted to the digital camera adjustment device 200
(Step P5).

The CPU 2072 of the computer 207
When the AWB evaluation values of R, G, and B are received, ΣR, ΣG, and ΣB of the AWB evaluation values of R, G, and B are calculated (step S8). Subsequently, the CPU 2072 determines that
ΣG, ΣB / ΣG are calculated (step S9), and the value of the counter K is incremented by “1” (step S1).
0).

Subsequently, the CPU 2072 determines whether or not ΣR / ΣG
It is determined whether or not ΣB / ΣG is within a specified value (near 1) (step S11). If ΣR / ΣG and ΣB / ΣG are within specified values, the gains of R and B at this time are determined. Is the AWB adjustment gain, and the CPU 12 of the digital camera
1 (step S12). Digital camera 10
When the CPU 121 of 0 receives the R and B AWB adjustment gains, it writes the gain to the flash memory 130 (step P6).

On the other hand, in step S11, {R /}
If G and ΣB / ΣG are not within the specified values (near 1), the process shifts to step S13 to determine whether the value of the counter K, that is, the number of adjustments is larger than the specified number N, and K> N.
If so, it is determined that the digital camera or the environmental condition is abnormal, and the fact is displayed on the display 208,
Notify the operator (step S15).

On the other hand, if K> N is not satisfied, step S
14, the R and B gains are calculated so that ΣR / ΣG and ΣB / ΣG are close to 1, and the calculated R and B gains and the C value of the digital camera indicate that photography should be performed again.
It is sent to the PU 2072 (step S14). In response, the CPU 121 of the digital camera 100 applies the calculated R and B gains to the white balance adjustment circuit 107.
4 is set to the multiplier 1074r and the multiplier 1074b,
Photographing is performed (step P4), and the AWB evaluation value is transmitted again (step P5). And the CPU of the computer
2072 calculates ΣR, ΣG, ΣB (step S8), calculates ΣR / ΣG, ΣB / ΣG (step S9), increments the value of the counter K by “1” (step S10), and sets ΣR / ΣG and ΣB / Σ
This processing (steps S14, P4, P5, S8,...) Is performed up to the specified number N until G falls within the specified value (near 1).
S9, S10, S11, S13) are repeated.

The above processing (steps S4 to S1)
4. Steps P3 to P6) are performed using filters W4 and W4.
Performed for each of C10, C4, W16, and AWB under each lighting condition
The adjustment gain is written to the flash memory 130.

In the above-described processing, when the number of adjustments is larger than the specified number, it is determined that the digital camera or the environmental condition is abnormal, and the display 20 is notified of the abnormality.
8 is displayed to notify the operator, but when the adjustment time exceeds a predetermined time, it may be determined that the digital camera or the environmental condition is abnormal.

As described above, in the digital camera 100 according to the present embodiment, the CCD 103 converts the subject light into an electric signal via the lens unit 101 and outputs it as a color image signal. A
The A / D converter 106 performs A / D conversion and outputs the digital color image signal as a digital color image signal. The IPP 107 outputs an AW corresponding to luminance data of each color component (RGB) of the digital color image signal.
A CPU (Auto White Balance) evaluation value is output, and the CPU 121 refers to the appropriate gain value under each lighting condition stored in the flash memory 130 and outputs the A value output from the IPP 107 within the set color temperature range.
An appropriate gain value corresponding to the WB evaluation value is calculated, and the calculated appropriate gain is set in the white balance adjustment unit 1074 to perform the AWB adjustment. Can be reproduced.

The digital camera 10 according to the present embodiment
0, the CCD 103 is the lens unit 101
The object light is converted into an electric signal through the interface and output as a color image signal, and the color image signal is converted into an A / D converter 10
6 and outputs the digital color image signal as a digital color image signal. The IPP 107 generates an AWB (Auto White Balance) corresponding to the luminance data of each color component (RGB) of the digital color image signal within the set luminance range.
e) The evaluation value is output, and the CPU 121 refers to the appropriate gain value under each lighting condition stored in the flash memory 130 and corresponds to the AWB evaluation value output from the IPP 107 within the set color temperature range. The appropriate gain value to be calculated is calculated, and the calculated appropriate gain is used as the white balance adjustment unit 1.
Since AWB adjustment is performed by setting to 074, even if the color temperature of the light source changes, white can be properly reproduced, and the calculation time can be shortened.

[0045]

According to a first aspect of the present invention, there is provided a digital camera which converts an object light passed through an optical system into an electric signal and outputs it as a color image signal, and an A / D converter for converting the color image signal into an A / D signal.
A / D that converts and outputs as digital color image signal
Conversion means, white detection range setting means for setting a color temperature range to be adjusted for white balance, and AWB (Auto White Bal) for each color component (RGB) of the digital color image signal in accordance with the luminance data of each color component.
Ance) AWB evaluation means for outputting an evaluation value, AWB adjustment means for adjusting the gain of at least two colors of the digital color image signal, storage means for storing appropriate gain values under a plurality of illumination conditions, and storage means With reference to the stored proper gain value, the AW output from the AWB evaluation means within the color temperature range set by the white detection range setting means.
AWB control means for calculating an appropriate gain value corresponding to the B evaluation value and setting the gain of the AWB adjustment means is provided, so that even if the color temperature of the light source changes, white is appropriately reproduced. It is possible to do.

The digital camera according to claim 2 is
An image sensor that converts subject light via an optical system into an electric signal and outputs the signal as a color image signal;
A that outputs a digital color image signal after A / D conversion
/ D conversion means, white detection range setting means for setting a color temperature range to be adjusted for white balance, detection brightness range setting means for setting a brightness range detected by the AWB evaluation means, and detection brightness range setting means. Within the set luminance range, AWB (Auto White Ba) according to the luminance data of each color component (RGB) of the digital color image signal.
said AWB evaluation means for outputting an evaluation value;
AWB adjusting means for adjusting the gain of at least two colors of the digital color image signal, storage means for storing appropriate gain values under a plurality of lighting conditions, and white gain by referring to the appropriate gain values stored in the storage means. Within the color temperature range set by the detection range setting means, A
Calculate an appropriate gain value corresponding to the WB evaluation value and calculate the AWB
AWB control means for setting the gain of the adjustment means is provided, so that white can be properly reproduced even if the color temperature of the light source changes, and the calculation time can be reduced. It becomes possible.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a digital camera according to an embodiment.

FIG. 2 is a diagram illustrating an example of a specific configuration of the IPP of FIG. 1;

FIG. 3 is a diagram showing an external configuration of a digital camera adjustment device according to the present embodiment.

FIG. 4 is a configuration diagram of a digital camera adjustment system according to the present embodiment.

FIG. 5 is a diagram showing a configuration of a computer of FIG.

FIG. 6 is a flowchart illustrating a processing procedure of AWB adjustment.

FIG. 7 is a diagram showing a display menu.

FIG. 8 is a diagram showing a selection menu.

[Explanation of symbols]

REFERENCE SIGNS LIST 100 Digital camera 101 Lens 102 Mechanical mechanism including autofocus 103 CCD (charge coupled device) 104 CDS (correlated double sampling) circuit 105 Variable gain amplifier (AGC amplifier) 106 A / D converter 107 IPP (Image Pre-Processor) ) 108 DCT (Discrete Cosine Transform) 109 Coder (Huffman Encoder / Decoder) 110 MCC (Memory Card Controller) 111 RAM (Internal Memory) 112 PC Card Interface 121 CPU 122 Display Unit 123 Operation Unit 125 Motor Driver 126 SG Unit 127 Strobe 128 Battery 129 DC-DC converter 130 Flash memory 150 PC card 200 Digital camera adjustment device 201 Digital camera supply power supply 202 Adapter 203 Monitor 204 Vector Corp 205 Waveform monitor 206 Light source 207 Computer 208 Display 209 GPIBI / F 210 Adjusting jig body 211 Control box 212 Filter switching device 1071 Color separation unit 1072 Signal interpolation unit 1073 Pedestal adjustment unit 1074 White balance adjustment unit (white balance adjustment unit) 1075 Digital gain adjustment unit 1076 γ conversion unit 1077 matrix unit 1078 video signal processing unit 1079 Y operation unit 1080 BPF 1081 AF evaluation value circuit 1082 AE evaluation value circuit 1083 Y operation unit 1084 AWB evaluation value circuit 1085 CPU I / F 1086 DCTI / F 1075r, 1075g, 1075b Multiplier 2071 Input unit 2072 CPU 2073 ROM 2074 RAM

Claims (2)

[Claims] 1. An imaging device that converts subject light via an optical system into an electric signal and outputs the signal as a color image signal, and an A / D that A / D converts the color image signal and outputs it as a digital color image signal. Conversion means; white detection range setting means for setting a color temperature range to be adjusted for white balance; and each color component (RGB) of the digital color image signal,
AWB (Auto) corresponding to the luminance data of each color component
AWB that outputs an evaluation value (White Balance)
Evaluation means; AWB adjustment means for adjusting the gain of at least two colors of the digital color image signal; storage means for storing appropriate gain values under a plurality of illumination conditions; and proper gain values stored in the storage means And calculating an appropriate gain value corresponding to the AWB evaluation value output from the AWB evaluation means within the color temperature range set by the white detection range setting means, and adjusting the gain of the AWB adjustment means. A digital camera comprising: AWB control means for setting. 2. An image pickup device for converting subject light via an optical system into an electric signal and outputting the same as a color image signal, and an A / D for converting the color image signal into an analog signal and outputting the digital image signal as a digital color image signal. Conversion means; white detection range setting means for setting a color temperature range to be adjusted for white balance; detection brightness range setting means for setting a brightness range detected by AWB evaluation means; and setting by the detection brightness range setting means. Within the specified brightness range,
AWB (Auto White Ba) corresponding to luminance data of each color component (RGB) of the digital color image signal
(Lance) the AWB evaluation means for outputting an evaluation value; AWB adjustment means for adjusting the gain of at least two colors of the digital color image signal; storage means for storing appropriate gain values under a plurality of lighting conditions; With reference to the appropriate gain value stored in the storage means, an appropriate gain value corresponding to the AWB evaluation value output from the AWB evaluation means is calculated within the color temperature range set by the white detection range setting means. And AWB control means for setting a gain of the AWB adjustment means.