JP2002218478A - Method for controlling auto white balance for digital camera and digital camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To satisfactorily control the white balance of each color image signal obtained at the time of performing bracketing photographing. SOLUTION: When a shutter button is pressed down in a bracketing mode (step S36), an object is consecutively and respectively photographed at an exposure value lower than a proper exposure value, the proper exposure value and an exposure value higher than the proper exposure value, and R, G and B signals obtained by the respective photographing are once stored in a memory (step S38, S40 and S42). A signal white balance correction value is next calculated on the basis of the R, G and B signals for the three photographs (step S44). The R, G and B signals for the three photographs are respectively subjected to white balance control based on the white balance correction value (step S46).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic white balance control method for a digital camera and a digital camera, and more particularly to an automatic white balance control method and a digital camera for a digital camera having a bracketing photographing function.

[0002]

2. Description of the Related Art In recent years, there has been proposed a digital camera using a CCD or the like as an imaging device for performing bracketing photography (Japanese Patent Laid-Open No. 11-4380). When the bracketing shooting is instructed, this digital camera does not change the exposure stepwise and shoots a plurality of times. Instead, image data obtained by one shooting is changed by, for example, ± 1 EV by an exposure changing circuit. Image data with different exposures is generated.

[0003]

In the above-mentioned Japanese Patent Application Laid-Open No. 11-4380, there is a description of controlling the white balance at the time of bracketing shooting, but there is no description of how to actually control the white balance. .

The present invention has been made in view of such circumstances, and an automatic white balance control method and a digital camera for a digital camera capable of favorably controlling the white balance of each color image signal obtained during bracketing shooting. The purpose is to provide.

[0005]

In order to achieve the above object, the invention according to claim 1 of the present application is directed to a proper exposure value, an exposure value underexposure than the proper exposure value, and / or an overexposure. In a digital camera having a bracketing shooting function for continuously shooting a subject with a plurality of exposure values including an exposure value, a single white balance correction based on a plurality of color image signals obtained at the time of bracketing shooting A value is obtained, and white balance control is performed on each of the plurality of color image signals based on the white balance correction value.

That is, a plurality of color image signals obtained at the time of bracketing photographing are respectively subjected to white balance control based on the same white balance correction value. Of the color image signal. Accordingly, since the amount of information is larger than when a white balance correction value is obtained based on a specific one color image signal of a plurality of color image signals obtained during bracketing shooting, more appropriate white balance correction is performed. The value can be determined.

According to a second aspect of the present invention, when a single white balance correction value is obtained based on the plurality of color image signals, only a color image signal within a preset luminance range is used. In this case, the white balance correction value is obtained.

That is, a color image signal of a saturated pixel or a color image signal that is too dark and is subjected to reliability in the relationship of S / N is not used in obtaining a white balance correction value.

When a single white balance correction value is obtained based on the plurality of color image signals, a white balance correction value is applied to each of the plurality of color image signals. Calculating a degree of appropriateness for calculating the white balance correction value for each color image signal based on the appropriateness determined for each color image signal. And

That is, a plurality of color image signals are not treated equally when a single white balance correction value is obtained, and the color image signal closer to the proper exposure is related to the calculation of the white balance correction value. Increase the weight for the value.

According to a fourth aspect of the present invention, there is provided a digital camera which captures an image of a subject and outputs a color image signal indicating the subject, a brightness measuring means for measuring brightness of the subject, and a subject measured by the brightness measuring means. First exposure determining means for determining an appropriate exposure value based on the luminance; an appropriate exposure value determined by the exposure determining means; and an exposure value and / or an exposure value underexposed than the appropriate exposure value. Second exposure determining means for determining a plurality of exposure values including an overexposure value, and exposure control means for controlling exposure in the imaging means, wherein the second exposure determining means determines the exposure value during bracketing shooting. Exposure control means for continuously controlling the exposure corresponding to each of the plurality of exposure values obtained, and a plurality of images obtained from the imaging means during the bracketing shooting Seeking a single white balance correction value based on the color image signal, and white balance control means for respectively controlling the white balance of the plurality of color image signals based on the white balance correction value,
It is characterized by having.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an automatic white balance control method for a digital camera according to the present invention;

FIG. 1 is a rear view of a digital camera according to the present invention, and FIG. 2 is a plan view of a mode dial provided on an upper surface of the camera.

As shown in FIG. 2, the mode dial 1 is rotated in such a manner that the icons 1A to 1F on the dial match the mark M, so that a continuous shooting / bracketing mode is set.
The photographing mode can be set to one of a manual photographing mode, an automatic photographing mode, a portrait mode, a landscape mode, and a night scene mode. In FIG. 2, the continuous shooting / bracketing mode is set. In the center of the mode dial 1, there is provided a shutter button 2 having a switch S1 which is turned on when pressed halfway and a switch S2 which is turned on when pressed fully.

On the back of the digital camera, as shown in FIG. 1, a viewfinder eyepiece 3, a shift key 4, a display key 5, a shooting mode / playback mode switching lever 6, a cancel key 7, an execution key 8, and a multi-function A cross key 9 and a liquid crystal monitor 52 are provided.

FIG. 3 is a block diagram showing the internal configuration of the digital camera shown in FIG.

In FIG. 1, a photographic lens 10 and an aperture 1
The subject image formed on the light receiving surface of the solid-state imaging device (CCD) 14 through the sensor 2 is converted by each sensor into signal charges of an amount corresponding to the amount of incident light. The signal charge thus accumulated is read out to the shift register by a read gate pulse applied from the CCD drive circuit 16, and is sequentially read out as a voltage signal corresponding to the signal charge by the register transfer pulse. Note that the CCD 14 has a so-called electronic shutter function that can sweep out the stored signal charges by a shutter gate pulse and thereby control the charge storage time (shutter speed).

The voltage signals sequentially read from the CCD 14 are applied to a correlated double sampling circuit (CDS circuit) 18, where the R, G, and B signals for each pixel are sampled and held, and an A / D converter is provided. Added to 20. A
The / D converter 20 converts the R, G, and B signals sequentially applied from the CDS circuit 18 into 10-bit (0 to 1023) digital R, G, and B signals and outputs the digital R, G, and B signals. The CCD drive circuit 16, CDS circuit 18, and A / D converter 20
It is driven in synchronization with a timing signal applied from the timing generation circuit 22.

R output from the A / D converter 18
The G and B signals are temporarily stored in the memory 24, and thereafter, the R, G and B signals stored in the memory 24 are applied to a digital signal processing circuit 26. Digital signal processing circuit 26
Are a synchronization circuit 28, a white balance adjustment circuit 30,
It comprises a gamma correction circuit 32, a YC signal creation circuit 34, and a memory 36.

The synchronizing circuit 28 converts the dot-sequential R, G, B signals read from the memory 24 into a simultaneous signal,
The G and B signals are output to the white balance adjustment circuit 30 at the same time. The white balance adjustment circuit 30 includes R, G, B
Multiplier 30 for respectively increasing and decreasing the digital value of the signal
It comprises R, 30G, and 30B, and the R, G, and B signals are applied to multipliers 30R, 30G, and 30B, respectively. The other inputs of the multipliers 30R, 30G, 30B include:
A white balance correction value (gain value) Rg for white balance control from a central processing unit (CPU) 38;
Gg and Bg are added, and the multipliers 30R, 30G,
30B multiplies each of the two inputs, and outputs the R ′, G ′, and B ′ signals whose white balance has been adjusted by the multiplication to the gamma correction circuit 32. The details of the white balance correction values Rg, Gg, Bg applied from the CPU 38 to the white balance adjustment circuit 30 will be described later.

The gamma correction circuit 32 changes the input / output characteristics so that the R ', G', and B 'signals whose white balance has been adjusted have desired gamma characteristics, and converts the 10-bit signal into an 8-bit signal. And outputs the result to the YC signal creation circuit 34. The YC signal generation circuit 34 generates a luminance signal Y and chroma signals Cr and Cb from the gamma-corrected R, G, and B signals. The luminance signal Y and the chroma signals Cr and Cb (YC signals) are stored in the memory 36 in the same memory space as the memory 24.

The YC signal stored in the memory 36 at the time of photographing is compressed into a predetermined format by a compression / expansion circuit 54, and then recorded on a recording medium such as a memory card by a recording unit 56.

The CPU 38 controls all the circuits based on the input from the camera operation unit 40 including the mode dial 1, the shutter button 2 and the like shown in FIG. 1, and performs auto focus, automatic exposure control, auto white balance, etc. Control. This autofocus control is performed, for example, so that the high-frequency component of the G signal is maximized.
This is a contrast AF for moving the photographing lens 10 to a focusing position via the driving unit 42 so that the high-frequency component of the G signal becomes maximum when the shutter button 2 is half-pressed.

In the automatic exposure control, the R, G, and B signals are fetched up to four times at a predetermined exposure or higher as shown in FIG. 4 and are integrated based on the integrated value of these R, G, and B signals. To obtain the subject brightness (shooting EV value)
The aperture value and shutter speed at the time of shooting are finally determined based on the values.

When the shutter button is fully pressed, the aperture 12 is driven via the aperture drive unit 44 so that the aperture value becomes the above determined aperture value, and the charge accumulation time by the electronic shutter so that the shutter speed becomes the determined shutter speed. Control.

Next, an automatic white balance control method will be described with reference to the flowchart shown in FIG. When the strobe light is emitted from the strobe light 46, white balance correction values Rg, Gg, and Bg for performing a good white balance with respect to the strobe light are added to the white balance adjustment circuit 30. The white balance control when no light is emitted will be described.

First, the photographing EV value obtained when the shutter button is half-pressed is obtained (step S10).

Subsequently, when the shutter button is fully pressed, A /
The R, G, and B signals for one screen output from the D converter 18 are temporarily stored in the memory 24. This one screen is divided into a plurality of areas (8 × 8) and An average integrated value for each color of the R, G, and B signals is determined, and a ratio R / G between the integrated value of the R signal and the integrated value of the G signal, and a ratio B between the integrated value of the B signal and the integrated value of the G signal. / G (Step S
12).

As for R / G and B / G determined for each divided area as described above, the divided area falls within any of the detection frames shown in the graph of FIG. Used to determine if The detection frames such as the shade-cloudy detection frame and the daylight color detection frame in FIG. 6 define the range of the color distribution of the light source type and the like.

The average integrated value of the R, G and B signals for each divided area is calculated by the integrating circuit 48 in FIG.
It is added to the CPU 38. The integrating circuit 48 and C
Multipliers 50R, 50G, and 50B are provided between the PU 38 and the multipliers 50R, 50G, and 50B, and an adjustment gain value for adjusting device variations is added to the multipliers 50R, 50G, and 50B.

Next, the evaluation value of the shade-cloudiness, the evaluation value of the fluorescent lamp (daylight, neutral white-white, warm white) and the evaluation value of the tungsten bulb are expressed by the following formulas.

[0032]

[Equation 1] Evaluation value of shade-cloudiness = F (outdoorness) × F
(Shade-cloudiness) x F (blue sky)

[0033]

[Number 2] daylight evaluation value = F ₁ (indoor-ness) × F (daylight fluorescent lamp likeness)

[0034]

[Equation 3] Evaluation value of day white-white = F ₁ (indoorness) × F
(Lunch white-white fluorescent lighting)

[0035]

[Equation 4] Evaluation value of warm white = F ₁ (likeness of indoor) × F (likeness of warm white fluorescent lamp) × F (skin)

[0036]

Calculated based on the evaluation value of the bulb = F ₂ (indoor likeness) × F (like a bulb) × F (skin).

In the above equation (1), F (outdoor likelihood) is a value of a membership function representing outdoor likelihood using the photographing EV value as a variable as shown in FIG.
It can be obtained based on the photographing EV value acquired in step S10.

Further, F ₁ (indoor likelihood) in Equations (2) to (4) is a membership function representing the likelihood of indoor (fluorescent light) using the shooting EV value as a variable, as shown in FIG. Is the value, and F ₂ in [Equation 5] (indoor likeness)
Is the shooting EV value (numerical value in parentheses) as shown in FIG.
Is a value of a membership function representing indoor (tungsten bulb) likelihood.

F (shade-cloudiness) in the equation (1) is a divided area in which the EV value Evi of the divided area is 12 or less, and which falls within the shade-cloudy detection frame as shown in FIG. Is the value of a membership function that represents shade-cloudiness with the number of variables as a variable, and F (blue sky) is an area where the EV value Evi of the divided area exceeds 12.5,
As shown in FIG. 9, this is a value of a membership function that represents a blue sky with the number of divided areas that fall within the outdoor sunny detection frame as a variable.

Note that F (blue sky) takes a value that acts to decrease the evaluation value of shade-likeness as the number of areas entering the blue sky detection frame increases. Further, the luminance (E
The V value Evi) is given by the following equation:

[0041]

## EQU6 ## Evi = Ev + log ₂ (Gi / 45) where Ev: shooting EV value Gi: calculated based on the average integrated value of G in each area. 45 in the above equation is an appropriate value among the values after A / D conversion.

Similarly, F (daylight-like fluorescent lamp), F (day white-white fluorescent lamp), F (warm white fluorescent lamp), and F (light bulb-like) in Equations (2) to (5) are similarly used. ) Indicates the daylight color detection frame and the daylight white-shown in FIG.
It is a value of a membership function indicating the likelihood of a light bulb / fluorescent lamp shown in FIG. 11 using the number of areas included in the white detection frame, the warm white detection frame, and the tungsten light bulb detection frame as variables.

F (skin) in the equations (4) and (5) is a member representing the skin color shown in FIG. 12 with the number of areas falling within the skin color detection frame shown in FIG. 6 as a variable. This is the value of the ship function. Note that F (skin) acts to lower the evaluation value of the likeness of a light bulb as the number of areas in the skin color detection frame increases. This is because, in a scene with a flesh color, if white balance control is strongly applied to the tungsten bulb color, redness is skipped and the skin becomes whitish, and the complexion is deteriorated.

Now, when the evaluation value of shade-cloudiness, the evaluation value of daylight color, the evaluation value of day white-white, the evaluation value of warm white, and the evaluation value of electric bulb are calculated, of these five evaluation values, It is determined whether or not the maximum value is 0.4 or more (step S16 in FIG. 5). If the maximum value is 0.4 or more, white balance control is performed based on a white balance correction value suitable for the light source color of the evaluation value having the maximum value (step S18).

On the other hand, when the maximum value is less than 0.4,
Daylight (fine) is determined, and white balance control is performed based on a white balance correction value suitable for daylight (step S20).

Here, the white balance correction value is:
The following formula,

[0047]

## EQU7 ## White balance correction value = (auto setting value-fine) .times.evaluation value + fine. However, fine is 1.0. Further, the automatic setting value is prepared in advance for each light source color. The auto-setting values of shade-cloudy, neutral white-white, and tungsten bulb are selected as follows.

(1) When shade-cloudy is selected The number of divided areas falling within the cloudy detection frame shown in FIG. Use the set value. Alternatively, the auto setting value is calculated by increasing the weight of the area having a large number of the two auto setting values.

(2) When Day White-White is Selected The number of divided areas that fall into the day white-white detection frame divided into six areas shown in FIG. Adopt the value. Alternatively, the automatic setting values are calculated by increasing the weight of the six automatic setting values in descending order of the number.

(3) When a Tungsten Light Bulb is Selected The number of divided areas that fall within the tungsten detection frame divided into two areas shown in FIG. 6 is compared, and the auto setting value of the larger number is adopted. Or, for two auto set values,
The auto setting value is calculated by increasing the weight for the area having a large number.

The white balance correction values obtained by [Equation 7] are Rg, Gg, Bg, and the signals to be corrected are R, G, B.
If the correction result of the white balance adjustment circuit 30 is R ', G', B ', then R', G ', B'
Is:

[0052]

R '= Rg × RG ′ = Gg × GB ′ = Bg × B

Next, an automatic white balance control method during bracketing photographing according to the present invention will be described.

First, the icon 1A on the mode dial is set to the mark M (see FIG. 2), the shooting mode is set to the continuous shooting / bracketing mode, and then the execution key 8 is pressed. A display for selecting the exposure fluctuation width as shown in FIG. 1 is displayed. Here, by operating the up and down keys of the cross key 9, the amplitude of the exposure during bracketing shooting is set. Incidentally, as shown in FIG. 1, when the shake width is 0.6, for example, the proper exposure (photographing EV
Value), three bracketing shootings of underexposure and overexposure by ± 0.6 EV from the shooting EV value are performed. When the shake width is 0, the continuous shooting mode is set.

In FIG. 13, when the bracketing mode is set as described above and the shutter button 2 is half-pressed (the switch S1 is turned on), a photographing EV value is obtained. When fully pressed (switch S2 is turned on), bracketing photography is performed (steps S30 to S36).

In this bracketing photographing, step S
An aperture value and a shutter speed for obtaining an appropriate exposure are determined based on the photographing EV value acquired in step S32, and an aperture value and a shutter speed for underexposure and overexposure that are equal to or smaller than the appropriate exposure by a predetermined exposure swing width. To determine.

Then, images are sequentially taken in the order of underexposure, proper exposure, and overexposure, and the raw R, G, and B signals obtained by these three times of imaging are temporarily stored in the memory 24 (step). S38 to S42).

Next, a white balance correction value is calculated based on the three R, G, and B signals stored in the memory 24 (step S44).

In this case, for each divided area obtained by dividing one screen into 64 (= 8 × 8), the color information (R
/ G, B / G), and at the same time, the digital value (0 to 255) of the average luminance is calculated for each divided area. Then, as shown in FIG. 14, the digital value of the average luminance of the divided area is a bright divided area having a digital value larger than a preset upper limit value, and a dark divided area having a digital value smaller than a preset lower limit value. Color information is not used as white balance information. The bright divided area may contain saturated pixels in the divided area, and correct color information may not be obtained. Further, the dark divided area may cause a problem of CCD linearity. This is because correct color information may not be obtained due to noise or noise.

That is, the color information of the divided area in which the digital value of the average luminance of the divided area is within the range between the lower limit and the upper limit is used for calculating the white balance correction value. In a scene with many dark areas, data shot in over can be effectively used, and in a scene with many bright areas, data shot in under can be effectively used.

The upper limit value and the lower limit value are optimally set in accordance with the number of pixels in the divided area. The smaller the number of pixels in the divided area, the closer the upper limit value becomes to 255 and the lower limit value becomes 0. Is set to approach.

As described above, at the time of bracketing photographing, a single white balance correction value is obtained by using the color information of the divided areas of three images of the same scene with different exposures. If there is no digital value of the average luminance of the area exceeding the upper limit value or lower than the lower limit value, information three times as large as usual can be obtained, and the light source type can be accurately determined. The method of calculating the white balance correction value based on the color information of each divided area is as follows.
Since it has been described in detail with reference to the flowchart of FIG. 5 and the like, the description is omitted here.

Returning to the flowchart of FIG. 13, the white balance correction value obtained in step S44 is added to the white balance adjustment circuit 30 (see FIG. 3).
R obtained at the time of underexposure stored in the memory 24,
The G and B signals are applied to a white balance adjustment circuit 30 via a synchronization circuit 28, where the white balance is adjusted. Similarly, the white balance of the R, G, and B signals acquired at the time of proper exposure and at the time of overexposure is adjusted based on the same white balance correction value as described above (step S46).

Thereafter, the R, G, and B signals whose white balance has been adjusted are subjected to gamma correction and YC conversion and stored in the memory 36. Then, three images of underexposure, proper exposure and overexposure are displayed on the liquid crystal screen of the liquid crystal monitor 52 based on the YC signal stored in the memory 36 (step S48).

The photographer presses the execution key 8 when recording these three images, and presses the cancel key 7 when not recording (step S50). When the execution key 8 is pressed, the three YC signals stored in the memory 36 are compressed into a predetermined format and recorded on a recording medium such as a memory card (step S52).

In this embodiment, a single white balance correction value is obtained by treating the data of three images equally. However, the white balance correction value is calculated by weighting each of the three images. You may ask for it. For example, a divided area (effective divided area) in which the average luminance digital value falls within the range from the lower limit to the upper limit described in FIG.
The larger the number of images, the more likely it is that the image was captured with a more appropriate exposure. Therefore, the weight related to the calculation of the white balance correction value based on that image is increased, and conversely, the effective division area The smaller the number of images, the more likely it is that the image was captured with inappropriate exposure. Therefore, a smaller weight is assigned to the value related to the calculation of the white balance correction value based on the image. This weighting coefficient includes 0 depending on the degree of inappropriate exposure or the like. In this case, data of an image captured with the inappropriate exposure is not used for white balance.

In this embodiment, the type of the light source is specified, and the white balance correction value suitable for the specified light source type is obtained. However, the method of obtaining the white balance correction value is not limited to this. For example, the white balance correction value may be obtained using the Evans principle that the average of the colors of the entire screen becomes gray. Further, the number of sheets during bracketing shooting is not limited to this embodiment.

[0068]

As described above, according to the present invention, the white balance correction value is fixed at the time of bracketing photographing, so that the white balance of each frame does not change. Since a single common white balance correction value is obtained based on an image signal, the amount of information is smaller than when a white balance correction value is obtained from a specific one color image signal of a plurality of color image signals. In many cases, a more appropriate white balance correction value can be obtained.

[Brief description of the drawings]

FIG. 1 is a rear view of a digital camera according to the present invention.

FIG. 2 is a plan view of a mode dial provided on the upper surface of the digital camera shown in FIG.

FIG. 3 is a block diagram showing an internal configuration of the digital camera shown in FIG.

FIG. 4 is a diagram used to explain a method of obtaining a shooting EV value;

FIG. 5 is a flowchart used to explain an automatic white balance control method;

FIG. 6 is a graph showing a detection frame indicating a range of a color distribution such as a light source type.

FIG. 7 is a graph showing a membership function representing outdoorness;

FIG. 8 is a graph showing a membership function representing shade-cloudiness.

FIG. 9 is a graph showing a membership function representing a blue sky;

FIG. 10 is a graph showing a membership function representing indoorness.

FIG. 11 is a graph showing a membership function indicating the likeness of a light bulb and a fluorescent light.

FIG. 12 is a graph showing a membership function representing a skin color.

FIG. 13 is a flowchart used to describe an embodiment of an automatic white balance control method during bracketing shooting;

FIG. 14 is a diagram used to explain a difference in digital value of average luminance in divided areas of three images obtained during bracketing shooting;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Mode dial, 2 ... Shutter button, 8 ... Execute key, 9 ... Cross key, 10 ... Photo lens, 12 ... Aperture, 1
4: solid-state imaging device (CCD), 24, 36: memory, 2
6 Digital signal processing circuit, 30 White balance adjustment circuit, 30R, 30G, 30B Multiplier, 38 Central processing unit (CPU), 48 Integration circuit

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] January 22, 2001 (2001.1.2)
2)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] FIG.

[Correction method] Change

[Correction contents]

FIG. 13

Continued on the front page F term (reference) 2H002 DB02 DB17 EB09 GA06 GA33 HA01 JA07 5C022 AA13 AB12 AB17 AB31 AC03 AC31 AC42 AC69 5C065 AA03 BB02 BB48 CC01 DD02 GG30 GG32 5C066 AA01 CA08 EA14 GA01 GA05 KE03 KE11 KM07

Claims (4)

[Claims] 1. A bracketing system for continuously photographing a subject with a plurality of exposure values including an appropriate exposure value, an exposure value that is underexposed than the appropriate exposure value, and / or an exposure value that is overexposed. In a digital camera having a shooting function, a single white balance correction value is obtained based on a plurality of color image signals obtained during bracketing shooting, and the plurality of color image signals are respectively determined based on the white balance correction values. An automatic white balance control method for a digital camera, wherein white balance control is performed. 2. When a single white balance correction value is obtained based on the plurality of color image signals, the white balance correction value is calculated using only a color image signal within a predetermined luminance range. 2. The method according to claim 1, wherein the automatic white balance control is performed. 3. An appropriateness for calculating a white balance correction value for each of the plurality of color image signals when obtaining a single white balance correction value based on the plurality of color image signals. And weighting a value associated with the calculation of the white balance correction value for each color image signal based on the appropriateness determined for each color image signal. White balance control method for digital cameras. 4. An image pickup means for picking up an image of a subject and outputting a color image signal indicating the subject, a luminance measuring means for measuring the luminance of the subject, and an appropriate exposure value based on the luminance of the subject measured by the luminance measuring means. A first exposure determining means for determining; an appropriate exposure value determined by the exposure determining means;
An exposure value underexposure than the proper exposure value and / or
Or, a second exposure determining means for determining a plurality of exposure values including an overexposure exposure value, and an exposure controlling means for controlling exposure in the imaging means, wherein the second exposure determining means at the time of bracketing shooting Exposure control means for continuously controlling the exposure corresponding to each of the plurality of exposure values determined in accordance with the above, and a single white balance based on a plurality of color image signals obtained from said imaging means during said bracketing shooting And a white balance control means for obtaining a correction value and performing white balance control on each of the plurality of color image signals based on the white balance correction value.