JP2000004445A - Camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To apply proper white balance WB adjustment in response to a photographing scene. SOLUTION: Image data which are separated into R, G, B color components at a photographing section 3 and then received are given to a WB circuit 207, where the components are respectively level-converted at prescribed gains kR, kG, kB set by a main body control section 201, resulting in WB adjustment. A WB characteristics setting section 201d revises setting of an allowable gain range (KiL-KiH) (i=R, B) of the R, G color components based on an object distance detected by a range finding section 201a and a luminance of the object detected by a luminance discrimination section 201b and makes setting within the allowable gain range (KiL-KiH). The allowable gain range (KiL-KiH) is set wider as the luminance of the object and the object distance increase (highly possible in outdoor photographing scene). Excess WB adjustment with respect to a color failure scene is prevented by changing the allowable gain range (KiL-KiH) depending on an estimated photographing scene and proper WB adjustment is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera which photoelectrically converts a light image of a subject into image signals of three primary color components, performs predetermined image processing on the image signals, and records the image signals on a recording medium. More particularly, the present invention relates to a white balance adjustment process of an image signal.

[0002]

2. Description of the Related Art In a camera such as a digital camera or a video camera, which photoelectrically converts a light image of a subject into image signals of three primary color components, a white balance of the image signal is usually adjusted. This white balance adjustment adjusts the level ratio of the image signals of the R (red) and B (blue) color components to the image signal of the G (green) color component so that a white object is reproduced in white. However, in general, white balance adjustment (hereinafter, referred to as WB adjustment) in FIG. 14 is performed so that a color-biased subject (for example, a reddish subject) is not excessively corrected and color reproducibility is not impaired. As shown in the processing procedure, the gain for level adjustment with respect to the R and B color components is limited.

That is, in the white balance adjustment, first, an evaluation level V _R for WB adjustment is obtained from an image signal separated and output into R, G, and B color components from an image pickup device such as a CCD (Charge Coupled Device). , V _G , V
_B (for example, the average value of image signals for each of the R, G, and B color components) is calculated, and the level ratio V _R / _R of the R, B evaluation levels V _R , V _{B to} the _G evaluation level VG. V _G , V
_B / V _G is calculated respectively (# 100). Subsequently, the level ratio V _R / V _G is set to a predetermined allowable range (L _R).
~ H _R ) is determined (# 102),
If the level ratio V _R / V _G is not within the allowable range (L _R ~H _R) (NO at # 102), the allowable range of the level ratio V _R / V _G is allowable range (L _R to H _R) The gain k _R for adjusting the level of the R color component is changed so that the maximum value H _R or the minimum value L _R exceeds the value (# 104). That is, if _{H R <V R / V G} , so that the _{V R / V G = H R} , also, if _{V R / V G <L R} , and V _R / V _G = L _R So that the level adjustment gain k for the R color component
_R is changed. On the other hand, if within a predetermined tolerance level ratio V _R / V _G is set in advance _{(L R ~H R) (#} 1
02, YES), the gain k _R for the R color component is not changed.

[0004] Then, whether the level ratio V _B / V _G is in the preset predetermined allowable range (L _B to H _B) is discriminated (# 106), level ratio V _B / V _G if There not within a predetermined allowable range (L _B ~H _B) (at # 106 N
O), as in the case of level ratio V _R / V _G, level ratio V _B
/ V _G so that the maximum value H _B or a minimum value L _B exceeds the allowable range of the predetermined tolerance range (L _B to H _B), the gain k _B is changed for level adjustment for color components of B (#
108). On the other hand, if within a predetermined allowable range signal level ratio V _B / V _G is set in advance, respectively (L _B to H _B) (YES in # 106), the gain k for level adjustment for color components of B _B does not change.

Subsequently, a gain k _R for level adjustment for the R color component is set to a predetermined allowable gain range (K _RL to K _RL ).
K _RH ) is determined (# 110).
If the gain k _R for level adjustment for the color component is not within the allowable gain range (K _{RL to} K _RH ) (NO in # 110), the gain k _R is within the allowable gain range (K _{RL to} K _RH ). The level adjustment gain k _R for the R color component so that the lower limit K _RL or the upper limit K _RH exceeds the allowable range.
Is changed (# 112). That is, if k _R <K _RL, so that the k _R = K _RL, also, if K _RH <k _R, so that the k _R = K _RH, for the level adjustment for the color components of R of gain k _R is changed. On the other hand, if the gain k _R for adjusting the level of the R color component is within the set allowable gain range (K _{RL to} K _RH ) (YES in # 110), the level adjusting gain for the R color component is set. Gain k
_R remains unchanged.

Subsequently, an allowable gain range (K _BL -K _BL) in which a gain k _B for level adjustment for the B color component is set.
K _BH ) is determined (# 114).
If the gain k _BR for level adjustment for the color component is not within the allowable gain range (K _{BL to} K _BH ) (NO in # 114), the gain k _B falls within the allowable gain range (K _{BL to} K _BH ). The gain k _B for adjusting the level of the B color component so that the lower limit value K _BL or the upper limit value K _BH exceeds the allowable range.
Is changed (# 116), and the process ends. That is,
If k _B <K _BL , then k _B = K _BL, and K
If _BH <k _B, so that the k _B = K _BH, gain k _B for level adjustment for the color component of B is changed. On the other hand, if the level adjustment gain k _B for the B color component falls within the set allowable gain range (K _{BL to} K _BH ) (YES in # 114), the level adjustment gain for the B color component is obtained. k _B is not changed.

[0007]

The conventional WB
In the adjustment, the lower limit values K _RL and K _BL and the upper limit values K _RH and K _RH of the gains k _R and k _B for level adjustment for the R and B color components, respectively.
Because K _BH is set in advance fixedly, the lower limit value K _RL so as to correspond to various color light source, K _BL and the upper limit value K _RH,
When trying to set _KBH , the allowable gain range ( _{KRL to} KRL)
_{RH), (K BL ~K BH} ) is widened, color reproducibility with respect to color failure scene is unnatural. That is, for example, an excessive WB adjustment may be performed on a reddish photographing scene such as a sunset scene, resulting in an image in which the atmosphere of the sunset is impaired.

Considering this problem, the allowable gain range (K _RL
ＫK _RH ) and (K _BL ＫK _BH ) may be set to be small. However, in this case, the light source colors to be properly adjusted in WB are limited, and the significance of automatically adjusting WB is lost. However, the operability is significantly reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and estimates a photographing scene (ie, a range of light source colors) based on a subject luminance or a subject distance, and based on the estimated value, an allowable gain range in WB adjustment. To provide a camera that can perform suitable WB adjustment by changing the setting of.

[0010]

According to the present invention, a light image of a subject is photoelectrically converted into image data of three primary color components by a color image pickup means and taken in, and the image data of the color components are respectively corresponded by white balance adjusting means. In a camera in which the white balance of a captured image is adjusted by amplifying with a predetermined gain within an allowable gain range, a luminance detecting means for detecting the luminance of the subject, and a luminance of the subject detected by the luminance detecting means. Gain range changing means for changing the allowable gain range so that the range becomes narrower as the brightness of the subject increases (claim 1).

According to the above arrangement, the brightness of the subject is detected at the time of photographing, and the allowable gain range (K _1L) for adjusting the white balance with respect to the image data V ₁ , V ₂ , V ₃ of each of the _three primary colors based on the detection result. ~ K _1H ), (K _2L ~
K _2H ) and (K _{3L to} K _3H ) are set. At this time, when the brightness of the subject is large, the shooting scene is assumed to be taken outdoors, and the allowable gain range (K _{iL to} K _iH ) (i = 1, 2, 2)
3) is set narrow, and when the subject brightness is low, the shooting scene may be indoor as well as outdoor.
The allowable gain range (K _{iL to} K _iH ) is set wide.

The image data V ₁ , V ₂ ,
V ₃ is a set allowable gain range (K _{1L to} K _1H ),
Amplification is performed with predetermined gains k ₁ , k ₂ , and k ₃ within (K _{2L to} K _2H ) and (K _{3L to} K _3H ), whereby the white balance of the captured image is adjusted. That is, in a normal shooting scene, the image data V ₁ , V ₂ , and V ₃ of each color component are set such that the average level of each color component is equal (ie, k ₁
V ₁ : k ₂ · V ₂ , k ₃ · V ₃ ≒ 1: 1: 1), and are amplified with predetermined gains k ₁ , k ₂ , k ₃ , and in the color feria scene, the relevant color feria One or two gains k _i (i = 1, 2, 3) are set in the allowable gain range (K _{iL to} K 1) so that the biased color of the scene is not excessively corrected.
_iH ) is set to a lower limit K _iL or an upper limit K _iH ,
Image data V _i of the corresponding color component, the gain K
_iL (or K _iH ), the image data V of other color components
_i is a predetermined gain k _i within an allowable gain range (K _{iL to} K _iH ).
Amplified by

Further, according to the present invention, a light image of a subject is photoelectrically converted into image data of three primary color components by a color image pickup means and taken in, and the white balance adjustment means converts the color component image data within a corresponding allowable gain range. In a camera in which the white balance of a captured image is adjusted by amplifying by a predetermined gain, distance detection means for detecting a distance to the subject, and a distance to the subject detected by the distance detection means. Gain range changing means for changing the allowable gain range so that the range becomes narrower as the distance to the distance increases.

According to the above arrangement, the distance to the subject is detected at the time of photographing, and the allowable gain range (K) for adjusting the white balance with respect to the image data V ₁ , V ₂ , V ₃ of each of the _three primary color components is detected based on the detection result. _{1L ~K 1H), (K 2L} ~K
_2H), are set (K _3L ~K _3H). At this time, when the distance to the subject is large, the shooting scene is assumed to be taken outdoors, and the allowable gain range (K _{iL to} K _iH ) (i = 1,
(2) and (3) are set to be narrow, and when the distance to the subject is small, the photographing scene may be indoor as well as outdoor. Therefore, the allowable gain range (K _{iL to} K _iH ) is set wide.

The image data V ₁ , V ₂ ,
V ₃ is a set allowable gain range (K _{1L to} K _1H ),
Amplification is performed with predetermined gains k ₁ , k ₂ , and k ₃ within (K _{2L to} K _2H ) and (K _{3L to} K _3H ), whereby the white balance of the captured image is adjusted.

Also, according to the present invention, the subject light image is photoelectrically converted into image data of three primary color components by a color image pickup means and taken in, and the white balance adjusting means converts the color component image data into a corresponding allowable gain range. In a camera in which the white balance of a captured image is adjusted by amplifying by a predetermined gain, a luminance detecting means for detecting the luminance of a subject, a distance detecting means for detecting a distance to the subject, the luminance detecting means, Based on the brightness of the subject and the distance to the subject detected by the distance detecting means,
And gain range changing means for changing the allowable gain range so that the range becomes narrower as the luminance of the subject increases and the distance to the subject increases (claim 3).

According to the above arrangement, the luminance of the subject is detected at the time of photographing, and the distance to the subject is detected.
Based on these detection results, allowable gain ranges (K _{1L to} K _1H ), (K _{2L to} K _2H ), (K _{3L to} K _3L ) for image data V ₁ , V ₂ , and V ₃ of each of the _three primary colors are adjusted.
To K _3H ) are set. At this time, when the subject brightness is large and the distance to the subject is large, the shooting scene is assumed to be taken outdoors and the allowable gain range (K _{iL to} K i
_iH ) (i = 1, 2, 3) is set to be narrow, the brightness of the subject is small, and when the distance to the subject is small, the shooting scene may be indoor as well as outdoor.
The allowable gain range (K _{iL to} K _iH ) is set wide.

The image data V ₁ , V ₂ ,
V ₃ is a set allowable gain range (K _{1L to} K _1H ),
Amplification is performed with predetermined gains k ₁ , k ₂ , and k ₃ within (K _{2L to} K _2H ) and (K _{3L to} K _3H ), whereby the white balance of the captured image is adjusted.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A digital camera according to the present invention will be described with reference to the drawings. FIG. 1 is a front view of a digital camera according to the present invention, and FIG. 2 is a rear view of the digital camera. 3 and 4 are a top view and a bottom view, respectively, of the digital camera.

The digital camera 1 comprises a box-shaped camera body 2 and a rectangular parallelepiped imaging section 3. The imaging unit 3 is rotatably mounted on the right side of the camera body 2 when viewed from the front, in a plane parallel to the right side. In the present embodiment, the imaging unit 3 is attached to the right side of the camera body 2, but may be attached to the left side of the camera body 2.

The image pickup unit 3 rotates within a range of approximately ± (90 + α) ° within the side surface of the camera body 2 with reference to the set position in FIGS. 1 and 2 (hereinafter, this position is referred to as a rotation reference position). You can do it. The imaging unit 3 includes a photographing lens including a macro zoom and a CCD (Charge Cou
It has an imaging device including a photoelectric conversion element such as a pled device, and converts an optical image of a subject into an image signal (an image signal composed of a charge signal photoelectrically converted by each pixel of a CCD) and captures the image signal. .

On the other hand, the camera body 2 is provided with an LCD (Liquid
A display unit 10 (see FIG. 2) composed of a Crystal Display).
It has a mounting portion for the memory card 17 (see FIG. 6) and a connection terminal 13 (see FIG. 2) to which a personal computer is externally connected, and mainly performs predetermined signal processing on the image signal captured by the imaging unit 3. Thereafter, processing such as display on the LCD display unit 10, recording on the memory card 17, and transfer to a personal computer is performed.

The image pickup unit 3 has a substantially rectangular parallelepiped shape having substantially the same length as the length of the camera body 2 in the height direction, and having substantially the same size as the width of the camera body 2. The image pickup section main body 3A is provided with a mounting section 3 for mounting the image pickup section 3 to the camera body section 2 on one side surface of the image pickup section main body 3A.
B is protruded.

As shown in FIG. 5, a macro zoom lens 301 and a focus actuator 306 for focusing the zoom macro lens 301 are provided inside the imaging section main body 3A. An imaging circuit 302 including a CCD color area sensor 303 is provided at an appropriate position. Further, a dimming circuit 30 including a dimming sensor 305 that receives reflected light of the flash light from the subject at an appropriate position in the imaging unit 3.
4 are provided. The light control sensor 305 is mounted on the mounting unit 3B.
(See FIG. 3).

On the other hand, as shown in FIG. 2, a side parallel to the back surface of the camera body 2 (the upper side when the image pickup unit 3 is rotated + 90 ° from the rotation reference position) is provided outside the imaging body 3A. A zoom lever 306 for changing the zoom ratio of the macro zoom lens 301 and switching between zoom and macro is provided on the side surface).

The zoom lever 306 is moved in the horizontal direction (the imaging unit 3).
With a lever that can slide in the direction perpendicular to the optical axis of
The zoom ratio of the macro zoom lens 301 is changed by sliding the zoom lever 306 laterally left and right at the zoom position PZ. In addition, the zoom lever 306 is slid rightward beyond the zoom position PZ to set the macro position PM.
Is set, the macro zoom lens 301 is switched to the macro lens. At the macro position PM, an image can be taken as close to the subject as about 50 cm.

As shown in FIG. 1, on the front surface of the camera body 2, a grip 4 is provided at an appropriate position on the left end, and a flash 5 is provided at an appropriate upper portion on the right end. As shown in FIG. 2, on the back of the camera body 2, an LCD display 10 for displaying a captured image on a monitor (corresponding to a viewfinder) and displaying and reproducing a recorded image is provided substantially at the center of the left end. Is provided.

An FL mode setting switch 11 related to flash emission is provided above the LCD display unit 10. The digital camera 1 has two modes related to flash emission: an "automatic emission mode" in which the flash 5 is automatically emitted according to the subject luminance, a "forced emission mode" in which the flash 5 is forcibly emitted regardless of the subject luminance, and the flash 5 Is provided, and each time the FL mode setting switch 11 is pressed, each mode of "automatic flash", "forced flash" and "flash disabled" is cyclically switched. The mode is selected and set.

The digital camera 1 has 1/8 and 1 /
For example, when the compression ratio setting switch 12 is slid to the right, the compression ratio K = 1/8 is set, and when it is slid to the left, the compression ratio K = 1/20. Is set. In the present embodiment,
Although two types of compression ratios K can be selected and set,
Three or more types of compression ratios K may be selectively set.

Further, a recording / reproduction mode setting switch 14 for switching and setting between "recording mode" and "reproduction mode" is provided at the upper right end on the rear surface of the camera body 2. A main switch 16 for turning on a main power supply is provided on the left side of the main switch. The recording mode is a mode in which a photograph is taken, and the reproduction mode is a mode in which a photographed image recorded in the memory card 17 is displayed on the LCD display unit 10.
Is a mode for reproducing and displaying. The recording / reproducing mode setting switch 14 also includes a two-contact slide switch. For example, sliding to the right sets the reproducing mode, and sliding to the left sets the recording mode. The main switch 16 is a push switch. When the switch is pressed in the on state, the power of the digital camera 1 is turned on. When the switch is pressed in the off state, the power is turned off.

As shown in FIG. 3, on the upper surface of the camera body 2, switches 6 and 7 are provided at the approximate center for frame advance when reproducing a recorded image. The switch 6 is a switch (hereinafter, referred to as an UP switch) for performing frame advance in a direction in which the frame number increases, and the switch 7 is a switch (hereinafter, referred to as a DOWN switch) for performing frame advance in a direction in which the frame number decreases. ). Further, the memory card 1 is located on the left side of the switch 7 when viewed from the rear side.
An erase switch 8 for erasing an image recorded in 7 is provided, and a shutter button 9 is provided on the upper right of the switch 6.

As shown in FIG. 6, a battery loading chamber for a power battery E and a memory card 1 are provided on the bottom of the camera body 2.
7 card loading chambers are provided, and the loading ports of both loading chambers are closed by clamshell type lids 15.

FIG. 7 is a block diagram of a control system of the digital camera 1. In the figure, the same members as those shown in FIGS. 1 to 6 are denoted by the same reference numerals.

The macro zoom lens 301 in the image pickup section 3 is provided with an aperture member (fixed aperture) having a fixed aperture amount. A signal processing circuit 307 and a timing generator (TG) 308 are components of the imaging circuit 302. CCD area sensor 303 (hereinafter, CC)
Abbreviated as D303. ) Is an image sensor composed of a CCD color area sensor, which converts the light image of the subject formed by the macro zoom lens 301 into R (red), G (green), B
The image signal is photoelectrically converted into an image signal of a (blue) color component (a signal composed of a signal sequence of pixel signals received by each pixel) and output. The timing generator 308 generates various timing pulses for controlling driving of the CCD 303.

The exposure control in the image pickup unit 3 is performed by adjusting the exposure amount of the CCD 303, that is, the charge accumulation time of the CCD 303 corresponding to the shutter speed, since the stop is a fixed stop. If an appropriate shutter speed cannot be set when the subject brightness is low, the CCD
By adjusting the level of the image signal output from 303, improper exposure due to insufficient exposure is corrected. That is, when the luminance is low, the exposure control is performed by combining the shutter speed and the gain adjustment. The level adjustment of the image signal is performed by the AGC circuit 3 in the signal processing circuit 307 described later.
This is performed in 07b gain adjustment.

The timing generator 308 is based on a reference clock transmitted from the camera
03 is generated. The timing generator 308 is, for example, a timing signal of integration start / end (exposure start / end), a readout control signal (horizontal synchronization signal, vertical synchronization signal, transfer signal, etc.) of a light receiving signal of each pixel.
, And outputs it to the CCD 303.

The signal processing circuit 307 performs predetermined analog signal processing on an image signal (analog signal) output from the CCD 303. The signal processing circuit 307
DS (correlated double sampling) circuit 307a and AGC
(Auto gain control) circuit 307b,
The noise of the image signal is reduced by the CDS circuit 307a, and the level of the image signal is adjusted by adjusting the gain of the AGC circuit 307b. The AGC circuit 3
The gain of 07a is automatically set by the main body control unit 201.

The light control circuit 304 controls the light emission amount of the flash 5 in flash photography to a predetermined light emission amount set by the main body control unit 201. In flash photography, the reflected light of the flash light from the subject is received by the light control sensor 305 at the same time as the start of exposure, and when the amount of received light reaches a predetermined light emission amount, the light control circuit 304 provides the light in the camera body 2. The light emission stop signal STP is output to the FL control circuit 202 thus set. FL control circuit 202
Stops the light emission of the flash 5 in response to the light emission stop signal STP, whereby the light emission amount of the flash 5 is controlled to a predetermined light emission amount.

A switch group 309 is a group of switches for detecting the set position of the zoom lever 306 of the macro zoom lens 301 and the set position of the image pickup unit 3 in the image pickup direction.

The FL control circuit 202 in the camera body 2 is a circuit for controlling light emission of the flash 5.
The FL control circuit 202 controls the presence / absence of light emission of the flash 5, the light emission amount, the light emission timing, and the like based on the control signal of the main body control unit 201, and emits the light of the flash 5 based on the light emission stop signal STP input from the light control circuit 304. Control the amount.

The reference clock generation circuit 203 is a circuit for generating a reference clock, and the timing control circuit 204 generates a clock CLK for the timing generator 308.
1 and a circuit for generating a clock CLK2 for the A / D converter 205. The reference clock generation circuit 203 and the timing control circuit 204 are driven by the main body control unit 201.
Is controlled by

The A / D converter 205 converts each pixel signal of the image signal input from the imaging section 3 into a 10-bit digital signal. The A / D converter 205 receives each pixel signal (analog signal) based on an A / D conversion clock CLK2 input from the timing control circuit 204.
Into a 10-bit digital signal.

The black level correction circuit 206 corrects the black level of the A / D converted pixel signal (hereinafter referred to as pixel data) to a reference black level. The WB circuit 207 adjusts the white balance of a captured image. Specifically, the level of the pixel data of each of the R, G, and B color components is converted using a level conversion table having the characteristics shown in FIG. The level conversion table is stored in the main body control unit 2.
01 is set for each captured image. The setting of the level conversion table will be described later.

The γ correction circuit 208 corrects the γ characteristics of the pixel data. As shown in FIG. 9, the γ correction circuit 208 has two types of γ correction tables having different γ characteristics, and performs γ correction of the pixel data using the γ correction table. In the γ correction processing, 10-bit pixel data is converted into 8-bit (256 gradations) pixel data. The reason why the pixel data before the γ correction processing is 10-bit data is to prevent the image quality from deteriorating when the γ correction is performed with the highly nonlinear γ characteristic. Also,
The pixel data of each of the R, G, and B color components undergoes a predetermined level conversion in the WB circuit 207, and these pixel data are respectively γ-corrected by a γ correction table.

In FIG. 9, the characteristic is the γ characteristic of γ = 0.45, and the captured image is displayed on the LCD display unit 10 (γ = 2.
2 (having a γ characteristic of 2). The LCD display unit 10 has a function as a view finder, and when the digital camera 1 is in a standby state for release, the CCD 3 is similar to the video camera.
The subject is imaged every 1/30 (second) by 03, and the captured images are sequentially displayed on the LCD display unit 10 on the monitor. In the image processing of the captured image in the monitor display, γ correction is performed according to the characteristics so that the image quality of the monitor image is suitable.

The characteristic is a γ characteristic of γ = 0.55, and a captured image of a standard photographic scene is stored in the memory card 1.
7 is applied to image processing at the time of recording. In the digital camera 1, a personal computer 19 can be connected to an external device, and the captured image recorded on the memory card 17 is normally reproduced on a monitor (having a γ characteristic of γ = 1.8) via the personal computer 19. Since it is considered to be displayed, release the memory card 17
The gamma correction is performed on the captured image instructed to be recorded on the monitor according to the characteristics, so that the image quality of the image reproduced on the monitor becomes suitable.

Returning to FIG. 7, the image memory 209 is a memory for storing the pixel data output from the gamma correction circuit 208. The image memory 209 has a storage capacity for one frame. That is, the image memory 209 has a CCD
When the pixel 303 has n rows and m columns of pixels, it has a storage capacity for pixel data of n × m pixels, and as shown in FIG. 10, each pixel data g (i, j) (i = 1 , 2 ... n, 1,
,... M) are stored at corresponding pixel positions (i, j).

The VRAM 210 is a buffer memory for pixel data reproduced and displayed on the LCD display unit 10. VR
The AM 210 has a storage capacity of pixel data corresponding to the number of pixels of the LCD display unit 10.

In the photographing standby state, each pixel data of an image (live view image) picked up by the image pickup unit 3 every 1/30 (second) is converted into a predetermined signal by the A / D converters 205 to γ correction circuit 208. After the processing, the image data is stored in the image memory 209, transferred to the VRAM 210 via the main body control unit 201, and displayed on the LCD display unit 10. Thus, the photographer can visually recognize the subject image from the image displayed on the LCD display unit 10. Further, in the reproduction mode, the image read from the memory card 17 is subjected to predetermined signal processing by the main body control unit 201 and then transferred to the VRAM 210, and
0 is reproduced and displayed.

The switch group 211 includes an UP switch 6, a D switch
These switches correspond to the OWN switch 7, the erase switch 8, the FL mode setting switch 11, the compression ratio setting switch 12, and the recording / reproducing mode setting switch 14.

The RTC 212 is a clock circuit for managing the shooting date and time. The RTC 212 is driven by a power supply battery (not shown) different from the main power supply battery.

The card I / F 213 is a memory card 17
An interface for writing image data into and reading image data from the memory. Also, communication I / F
Reference numeral 214 denotes an interface compliant with, for example, the RS-232C standard for externally connecting the personal computer 19 so that communication is possible.

The main body control section 201 is composed of a microcomputer, and controls the driving of each member in the image pickup section 3 and the camera main body section 2 so as to totally control the photographing operation of the digital camera 1. The main body control unit 201 includes a distance measuring unit 201a, a luminance determining unit 201b, a shutter speed (SS) setting unit 201c, and a WB characteristic determining unit 201d.

The distance measuring section 201a calculates the distance Dv to the subject.
Is to be detected. This distance information is used for setting gains of R and B color components in white balance adjustment described later. The distance measuring unit 201a detects the contrast of an image (live hue image) captured by the CCD 303 in a shooting standby state, and drives the focus actuator 306 such that the contrast is maximized. The distance Dv is detected. This detection processing is periodically performed, for example, in a cycle of one to several seconds. The brightness determination unit 201b calculates the brightness B of the subject.
In addition to detecting v, the brightness of the subject is determined. The brightness determination unit 201b detects the brightness Bv of the subject using the video image and determines the brightness of the subject. That is, as shown in FIG. 10, the luminance determination unit 201b sets the storage area of the image memory 209 to 9
B (1), B (2),... B (9), and the pixels of the G (green) color component included in each block B (r) (r = 1, 2,... 9) Using the data g _G (k, h), each block B (r)
Is calculated as the representative luminance data Bv (r). Specifically, the luminance data Bv (r) of each block B (r) is calculated by calculating the average value of the pixel data g _G (k, h) of the G (green) color component. Then, the brightness Bv of the subject is determined using the nine pieces of brightness data Bv (r), and the brightness is determined. As the luminance Bv of the subject, for example, luminance data Bv (5) of the block B (5) at the center of the screen is adopted as the luminance Bv, or nine luminance data Bv (r) (r = 1, 2,... 9)
Is determined by calculating a weighted average value of.

Each block B is obtained by using pixel data g _R (k, h), g _G (k, h) and g _B (k, h) of each color component of R, G and B.
The luminance data Bv (r) representing (r) may be calculated. That is, R, G, B at each pixel position (k, h)
Pixel data g _R (k, h), g _G (k, h), g _B (k, h)
At a predetermined ratio (eg, g _R : g _G : g _B = 4: 5: 1), and the luminance data Bv (k, k) at the pixel position (k, h) is added.
h) (= 0.4 g _R +0.5 g _G +0.1 g _B ) is calculated,
The luminance data Bv (i) of each block B (i) may be calculated by calculating the average value of the luminance data Bv (k, h).

The shutter speed setting section 201c sets a shutter speed (exposure time of the CCD 303). The shutter speed setting unit 201c has a table in which a plurality of shutter speeds Tv are set in advance, and uses the table based on the determination result of the brightness of the subject by the luminance determining unit 201b.
Set. That is, the shutter speed Tv is initially set to a predetermined value (for example, 1/128 (second)) when the camera is started, and the shutter speed setting unit 201c determines the brightness of the subject determined based on the image captured at the shutter speed Tv. Is too bright, the shutter speed T
v is increased by one step, and when it is too dark, the shutter speed Tv is decreased by one step. Also, the shutter speed T
Similarly, for the next image after the change of v, the brightness of the subject is determined, and the shutter speed Tv is changed based on the determination result. Similarly, the shutter speed setting unit 201c determines the brightness of the subject and sets the shutter speed Tv.
The shutter speed Tv is set appropriately after a certain period of time has been alternately repeated.

The WB characteristic setting section 201d is provided with the WB circuit 20
7 is to set a level conversion table.
Specifically, the respective slopes k _R , k _G , and k _{B of the} three level conversion characteristics shown in FIG. 8 (that is, gains k _R , k _G , and k _B of the respective color components of _R , _G , and _B ) are set. Is what you do.

[0058] In the white balance adjustment, to prevent an unnatural color reproduction due to excessive white-balance adjustment to the captured image of the so-called color failure scene, generally R, B color components gain k _R, certain restrictions on k _B is provided. Now, R, G, the evaluation level V _R for white balance adjustment for each color component of _B, V _G, V B
To the, R for the evaluation level V _G of G, valuation V _R, the level ratio V _R / V _G of V _B of B, V _B / V _G is allowable range of a preset level ratio respectively (L _R ~ H _R ), (L
_{B to} H _B ), the gain k of each of the R and B color components
_R, is k _B is set.

Therefore, the level ratio V _R / V _G is within the allowable range (L
_R to H _R) when the outside, V _R / V _G <L In _R V _R / V _G
= L such that _{R, also, V R / V G> H} R in V _R / V _G
= H _R , the gain k _{R of the R} color component is set, and when the level ratio V _B / V _G is out of the allowable range (L _{B to} H _B ), V _B / V _G <L in such a _{V B / V G = L B} B, also as a V _B / V _G> in _{H B V B / V G =} H B, the gain k _B B color components are set You.

Further, the gains k _R and k _{B of the R} and _B color components determined by the conditions of the allowable ranges of the level ratios V _R / V _G and V _B / V _G are respectively set to the predetermined allowable gain ranges ( K _RL ~K _RH), to fall within the (K _BL ~K _BH),
The gains k _R and k _{B of the} R and B color components are limited. That is, the gain k _{R of the R} color component is within the allowable gain range (K _RL
~ K _RH ), when k _R <K _RL , k _R = K _RL ,
When k _R > K _RH , the gain k of the R color component is set to k _R = K _{RH.
When R} is set and the gain k _{B of the B} color component is out of the allowable gain range (K _{BL to} K _BH ), k _B = K if k _B <K _BL.
If k _B > K _BH , the gain k _{B of the B} color component is set to k _B = K _BH .

In the present embodiment, the allowable gain range is not a fixed range, and the R and B colors are determined based on the subject distance Dv detected by the distance measuring unit 201a and the subject luminance Bv detected by the luminance determining unit 201b. permissible gain range of components (K _RL ~K _RH), so that (K _BL ~K _BH) was determined, to set the level conversion table for white balance adjustment based on the decision value.

As described above, taking into account the subject distance Dv and the subject brightness Bv, the allowable gain ranges (K
( _{RL to} K _RH ) and (K _{BL to} KB _H ) are changed and set in the allowable gain ranges (K _{RL to} K _RH ) of the gains k _R and k _B for the pixel data of the R and B color components in the white balance. ,
When (K _{BL to} K _BH ) is fixedly set, the permissible gain ranges (K _RL to K _R) of the gains k _R and k _B are required to correspond to various light source colors of natural light and artificial light. K _RH ),
(K _{BL to} KB _H ) is widened, and the white balance adjustment for the captured image of the color feria scene becomes improper.
Gain k _R in consideration of this problem Conversely, the allowable range of gain _{k B (K RL ~K RH)} , by setting narrow (K _BL ~K _BH),
This is because there is an inconvenience that the color of the light source for appropriately reproducing colors is limited.

Therefore, in the present embodiment, the object distance D
The shooting scene (that is, the light source color) or the shooting situation is estimated based on v and the subject luminance Bv, and the allowable gain range (K _RL ) of the appropriate gains k _R and k _B is estimated according to the estimation result.
K _RH ) and (K _{BL to} KB _H ).

Table 1 shows the object distance Dv and the object luminance B
v is an example of a table for determining the lower limit values K _RL and K _BL of the permissible gain range, and Table 2 shows the subject distance Dv
7 is an example of a table for determining upper limit values K _RH and K _BH of an allowable gain range based on a subject brightness Bv. Lower limit K _iL and the upper limit value K _iH "i" indicates that subscript is "R" or "B".

[0065] In this embodiment, R, permissible gain range of each color component of B (K _RL ~K _RH), using Table 1, Table 2 in common for setting (K _BL ~K _BH) However, individual tables may be created.

[0066]

[Table 1]

[0067]

[Table 2]

[0068] Table 1, numerical values in Table 2 for operation on the lower limit value K _iL when allocation and the upper limit value K _iH a preset reference gain (kr fold) the data values for the operation "32" It is a specific example given by the data value. Thus, for example, when the gain of the reference and kr = 1.2 times, Tables 1 and a lower limit value K _iL set by Table 2 and the upper limit value K _iH is respectively "14", "4
0 ”, the set allowable gain range (K _iL to
K _iH ) is ( _{14/32 to 40/32} ) = (0.43 times or more)
1.25 times).

In Tables 1 and 2, for example, the subject brightness B
If v and the subject distance Dv are substantially intermediate values,
Central values of both the table is set as a lower limit value K _iL and the upper limit value K _iH, permissible gain range (K _iL ~K _iH) is (18 (0.56k
r) to 41 (1.28kr)). Also, the subject brightness Bv
And if the object distance Dv is the minimum, the upper left corner of the values in Table 1 and Table 2 are set as the lower limit value K _iL and the upper limit value K _iH,
The allowable gain range (K _{iL to} K _iH ) is (5 (0.16kr) to 49
(1.53kr)), and the allowable gain range is wider on both the upper and lower sides than in the previous example. If the maximum is subject luminance Bv and object distance Dv Conversely, the value of the lower-right corner of Tables 1 and 2 are set as the lower limit value K _iL and the upper limit value K _iH, permissible gain range (K _iL ~K _iH) is (30 (0.94kr)-33 (1.03kr))
Thus, the allowable gain range becomes narrower in the upper and lower sides than in the previous example.

[0070] Table 1 and Table 2, the lower limit value K _iL and the upper limit value K _iH, according to the subject brightness Bv is larger, also larger set according to object distance Dv is larger I am trying to be. This is based on the following reasons.

That is, when the subject distance Dv is a short distance shorter than a predetermined distance, the shooting scene can be either outdoor or indoor. However, when the subject distance Dv is a long distance longer than the predetermined distance, the shooting scene is outdoor. High possibility of shooting scene. In addition, when the subject brightness Bv is medium brightness and low brightness lower than the predetermined brightness, both outdoor and indoor shooting scenes can be considered. However, when the subject brightness Bv is high brightness higher than the predetermined brightness, the shooting scene is outdoors. There is a high possibility of a shooting scene in fine weather or cloudy weather.

If it can be estimated that the scene is taken outdoors,
Since the light source is daylight on sunny or cloudy day, in white balance adjustment for a captured image in such a shooting scene, even if the allowable gain range is narrowed so as to be appropriate for this daylight, color reproduction can be performed. No particular problem is expected. On the other hand, when it is not possible to reliably estimate an outdoor shooting scene and an indoor shooting scene is also conceivable, artificial light such as a fluorescent lamp or tungsten light needs to be considered as a light source, which is appropriate for artificial light. As described above, the allowable gain range needs to be wider than that in the case where the scene is assumed to be an outdoor shooting scene.

Accordingly, when the subject distance Dv is large and the subject luminance Bv is large, the possibility of taking a photographed scene outdoors is high. Therefore, the allowable gain range is narrowed to the necessary minimum range, and the color reproducibility in outdoor photographing is reduced. Is increased, and as the subject distance Dv becomes smaller,
As the subject brightness Bv decreases, the allowable gain range is gradually widened, taking into account the possibility of indoor shooting scenes,
The color reproducibility under artificial light is not reduced. In the tables of Table 1 and Display 2, when the actual shooting scene is an outdoor low-brightness scene, the allowable gain range becomes wider than necessary for the daylight light source. Even if there is, it is not necessary to limit the allowable gain range to an appropriate range under fine weather, so that even if the allowable gain range is widened, no substantial inconvenience occurs.

Returning to FIG. 7, the main body control unit 201 further comprises:
In order to record a captured image, the image processing apparatus includes a filter unit 201e that performs a filtering process and a recorded image generation unit 201f that generates a compressed image. A reproduction image generation unit 201g for generating an image is provided.

The filter unit 201f corrects the high-frequency component of the image to be recorded by a digital filter to correct the image quality related to the outline. The recording image generation unit 201g applies JPEG such as two-dimensional DCT conversion and Huffman coding to the captured image on which the filtering process has been performed by the filter unit 201f.
(Joint Photographic Coding Experts Group) A predetermined compression process is performed to generate image data of a compressed image having the compression ratio K set by the compression ratio setting switch 12. In addition, the reproduced image generation unit 201g includes the memory card 1
Image data is read out from the LCD 7 and a captured image to be reproduced and displayed on the LCD display unit 10 is generated. Since the image recorded on the memory card 17 has been γ-corrected by the γ coefficient for monitoring (= 0.55), if this recorded image is reproduced on the LCD display unit 10 as it is, the γ coefficient and γ for LCD display are displayed. Since the contrast becomes strong and the image quality is strong due to the mismatch with the coefficient (= 0.45), the reproduced image generation unit 201g re-corrects the γ characteristic of the reproduced image when generating an image for reproducing the recorded image.

Therefore, in the recording mode, when the photographing is instructed by the shutter button 9 in the recording mode, the image data taken into the image memory 209 after the photographing is instructed is subjected to the image processing of the contour correction by the filter unit 201f. Is performed, a recorded image generation unit 201g generates a compressed image for image recording, and stores it in the memory card 17 together with index information (information such as a frame number, an exposure value, a shutter speed, and a compression ratio K) on the captured image. .

In the playback mode, when a playback frame is instructed in the playback mode, the main body control unit 201 reads out the image data (compressed data) of the playback frame from the memory card 17, and the playback image generation unit 201g outputs the image data. The image data for display is expanded to generate γ =
After performing γ correction with a γ characteristic of 0.82, the VRAM
The recorded image is transferred to 210 and the recorded image is reproduced and displayed on the LCD display unit 10.

Next, shooting control in the recording mode of the digital camera 1 will be described with reference to the flowcharts shown in FIGS.

The photographing control mainly comprises viewfinder processing, exposure control and image processing. The viewfinder process is a process of displaying a subject image on the LCD display unit 10 so that the photographed content can be visually recognized. In the viewfinder processing, a suitable adjustment of the shutter speed is also performed.

First, the shutter speed Tv is set to the initial value (1
/ 128 (seconds)) (# 2), and γ = 0.45.
After the characteristics (the characteristics in FIG. 9) are set (# 4), the CCD
Exposure of 303 is started (# 6). Then, when a predetermined exposure time (Tv = 1/128 (second)) has elapsed (# 8)
YES), the image signal picked up by the CCD 303 is read (# 10), and predetermined image processing is performed by the signal processing circuit 307 and the A / D converters 205 to γ correction circuit 208 (# 12). Are stored in the image memory 209 (# 14). The image data stored in the image memory 209 is immediately read out to the VRAM 210 and displayed on the LCD display unit 10 as a monitor (# 16).

Subsequently, the brightness data of the captured image is calculated (# 18), and it is determined whether or not the shutter speed Tv is appropriate based on the brightness data (# 20). For the luminance data, the captured image is divided into nine blocks B (1) to B (9) (see FIG. 10), and each block B (r) (r = 1, 2,...).
For each 9), the average value Bv (r) of the pixel data of the G (green) color component included in the block B (r) is calculated. Then, is the nine brightness data Bv (1) to BV (9) a too bright overall imaging image compared respectively with thresholds BV _L threshold BV _H and a low level of a predetermined high level (overexposed ), Whether the captured image is too dark (underexposure) as a whole, or appropriate.

If the captured image is too bright or too dark as a whole, it is determined that the shutter speed Tv is inappropriate (NO in # 20), and the shutter speed Tv is changed by one step according to the brightness of the captured image. (# 22)
Step # to determine whether shutter speed Tv is appropriate
Return to 6. That is, if the captured image is too bright as a whole, the shutter speed Tv is changed to a value smaller by one step, and if the captured image is too dark as a whole, the shutter speed Tv is changed to a value larger by one step. Return to # 6.

Then, the loop of steps # 6 to # 22 is repeated, and when the shutter speed Tv is set to an appropriate value (YES in # 20), whether the shutter button 9 is pressed and the release switch is turned on is determined. It is determined whether or not the release switch has been turned on (NO in # 24), and the flow returns to step # 2 to enter a release standby state (loop of # 6 to # 24).

Since the CCD 303 captures a frame image every 1/30 (second), the processes of steps # 6 to # 24 are performed for each frame image, and the shutter speed Tv is increased by one stage from the initial value. Alternatively, the shutter speed Tv is adjusted at the same time as the viewfinder processing. If the shutter speed Tv is renewed to a large value by the loop process of steps # 6 to # 24 and exceeds 1/30 (second), the process proceeds to step #.
The shutter speed Tv at 22 is fixed at 1/30 (second), and the gain of the AGC circuit 307 b in the signal processing circuit 307 is adjusted.

In the release standby state, when the shutter button 9 is pressed and the release switch is turned on (# 2)
(YES at 4), after a predetermined shutter speed Tv is set (# 26), exposure control is performed (# 28, # 3).
0). When a predetermined exposure time Tv has elapsed and the exposure is completed (YES in # 32), an image signal is read from the CCD 303 (# 32), and the signal processing circuit 307, A / A
Predetermined image processing is performed by the D converters 205 to γ correction circuit 208 (# 34).

Subsequently, predetermined image data for recording is generated by the recording image generating section 201f (# 36), and this image data is transferred to the memory card 17 to record a captured image (# 38). Then, the photographing operation is completed by recording the image data on the memory card 17, and the process returns to step # 2 to perform the next photographing.

Next, the white balance adjustment processing according to the present invention will be described with reference to the flowchart of FIG.

Note that this white balance adjustment processing
Each time an image is captured by the CCD 303, the main body control unit 20
1, a level conversion table for the WB circuit 207 is created based on the gains k _R and k _B of the R and G color components set in this process. When the camera is started, a level conversion table based on preset gain initial values k _R0 , k _G0 , and k _B0 is set in the WB circuit 207, and white balance processing of the first captured image is performed using this level conversion table. Done.

First, an image is picked up by the CCD 303, and the picked-up image is converted into A / D converters 205 to γ correction circuit 2.
08, the image memory 2
09, the subject distance Dv and the subject brightness Bv are detected using the captured image (# 40, # 4).
2).

Subsequently, evaluation levels V _R , V _G , V for adjusting the gain of the image of each color component of R, G, B are obtained.
With _B is calculated, R for the evaluation level V _G of R, valuation V _R of G, level ratio V _R / V _G of V _B, V _B
/ V _G is calculated respectively (# 44). The evaluation levels V _R , V _G , and V _B are, for example, the average values of the output levels of all the pixels constituting the image of each of the R, G, and B color components.

[0091] Then, whether the level ratio V _R / V _G is in the preset predetermined allowable range (L _R to H _R) is determined (# 46), level ratio V _R / V _G Is within the allowable range (L _R
If not entered to H _R) in (# 46 NO), the maximum value H _R or minimum L _R exceeds the allowable range of the level ratio V _R / V _G is allowable range (L _R to H _R) Thus, the gain k _R for the R color component is changed (# 48). That is, if _{H R <V R / V G} , so that the _{V R / V G = H R} , also, if _{V R / V G <L R} , and V _R / V _G = L _R Thus, the gain k _R for the R color component is changed. On the other hand, if within a predetermined tolerance level ratio V _R / V _G is set in advance (L _R ~H _R) (with # 46 YE
S) The gain k _R for the R color component is not changed.

[0092] Then, whether the level ratio V _B / V _G is in the preset predetermined allowable range (L _B to H _B) is discriminated (# 50), level ratio V _B / V _G If There not within a predetermined allowable range (L _B to H _B) (NO at # 50), as in the case of level ratio V _R / V _G, level ratio V _B / V _G is the predetermined allowable range ( L _B to H _B) the allowable range so that the maximum value H _B or a minimum value L _B exceeds the gain k _B is changed with respect to the color component of B (# 52). On the other hand, if within a predetermined allowable range signal level ratio V _B / V _G is set in advance, respectively (L _B to H _B) (YES at # 50), the gain k _B is not changed for the color component of B .

[0093] Subsequently, the above Table 1, is set the lower limit value K _iL and the upper limit value K _iH permissible gain range on the basis of the object distance Dv and the subject luminance Bv (K _iL ~K _iH) using the table shown in Table 2 Is performed (# 54). Further, it is determined whether or not the gain k _R for the R color component falls within the set allowable gain range (K _{RL to} K _RH ) (# 56), and the gain k _R for the R color component is set to the allowable gain range. (K _RL ~K _RH) (NO at # 56) had unless contained, the gain k _R is permissible gain range (K _RL ~K _RH) the permissible gain range limit values K _RL or the upper limit value K _RH exceeds the The gain k _R for the R color component is changed such that That is,
If k _R <K _RL , then k _R = K _RL and K
If _RH <k _R, so that the k _R = K _RH, the gain k _R is changed for the color components of R. On the other hand, the allowable gain range ( _KRL to _KRL) in which the gain kR for the _R color component is set.
K _RH ) (YES in # 56), the gain k _R for the R color component is not changed.

Subsequently, it is determined whether or not the gain k _B for the B color component falls within the set allowable gain range (K _{BL to} K _BH ) (# 60), and the gain k _BR for the B color component is determined. critical value K but unless within the allowable gain range (K _BL ~K _BH) of (NO at # 60), the gain k _B exceeds the permissible gain range of allowable gain range (K _BL ~K _BH)
The gain k _B for the color component of _B is changed so as to become _BL or the upper limit value K _BH (# 62), and the process ends. That is, if k _B <K _BL , the gain k _B for the B color component is set so that k _B = K _BL, and if K _BH <k _B , k _B = K _BH. Is changed. On the other hand, if the gain k _B for the B color component is within the set allowable gain range (K _{BL to} K _BH ) (YES in # 60), B
The gain k _B for the color component is not changed.

As described above, in the white balance adjustment in the WB circuit 207, the photographic scene is estimated based on the subject distance Dv and the subject brightness Bv. Gain k for component
_R, permissible gain range of _{k B (K RL ~K RH)} , (K BL ~
K _BH ) is narrowed to a range where white balance can be adjusted with respect to daytime light, and when it is necessary to consider indoor shooting scenes, the allowable gain ranges of the gains k _R and k _B for the R and G color components are required. Since (K _{RL to} K _RH ) and (K _{BL to} KB _H ) are made wider, it is possible to reduce color reproduction errors due to white balance adjustment. In particular, at least in an outdoor shooting scene, a suitable white balance adjustment can be reliably performed even in a color feria scene.

In the above embodiment, the object distance Dv and the object brightness Bv
Had been to set the lower limit value K _iL and the upper limit value K _iH permissible gain range (K _iL ~K _iH) in combination bets, based on one of the subject distance Dv or subject brightness Bv as a simple method permissible gain range (K _iL ~K _iH) lower limit K _iL and the upper limit value K _iH of Te may be set to. That is, set in Tables 1 and 2, for example, the middle row the lower limit value K _iL and the upper limit value K _iH permissible gain range on the basis of the object luminance Bv using data (third row) (K _iL ~K _iH) For example, using the data in the center column (third column) and the allowable gain range (K _iL to
Lower limit K _iL and the upper limit value K _iH of K _iH) may be set.

In the above embodiment, the digital camera has been described. However, the present invention is not limited to the digital camera, but can be applied to a video camera.

[0098]

As described above, according to the present invention,
The subject light image is photoelectrically converted into image data of the three primary color components by the color image pickup means, and is captured. The image data of each color component is amplified by a predetermined gain within a corresponding allowable gain range, thereby whitening the captured image. In a camera whose balance is adjusted, at least one of the subject brightness and the subject distance is detected, and based on these detection results, the subject brightness or the subject distance increases, or both the subject brightness and the subject distance increase. (Ie, as the possibility of an outdoor shooting scene increases), the allowable gain range is changed and set so that the range becomes narrower. WB adjustment with few errors is possible without excessive WB adjustment and unnatural color reproduction It made.

[Brief description of the drawings]

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

FIG. 2 is a rear view of the digital camera according to the present invention.

FIG. 3 is a top view of the digital camera according to the present invention.

FIG. 4 is a bottom view of the digital camera according to the present invention.

FIG. 5 is a diagram showing a schematic structure in an imaging unit.

FIG. 6 is a diagram showing a state in which a lid of a power battery and a memory card are opened.

FIG. 7 is a block diagram of a digital camera according to the present invention.

FIG. 8 is a diagram illustrating characteristics of a level conversion table.

FIG. 9 is a diagram showing γ characteristics of a γ correction table.

FIG. 10 is a diagram showing a storage position of each pixel data in an image memory.

FIG. 11 is a flowchart illustrating shooting control in a recording mode.

FIG. 12 is a flowchart illustrating shooting control in a recording mode.

FIG. 13 is a flowchart illustrating white balance adjustment processing.

FIG. 14 is a flowchart showing a conventional white balance adjustment process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Digital camera 2 Camera main body 201 Overall control part 201a Distance measuring part (distance detecting means) 201b Luminance determining part (luminance detecting means) 201c Shutter speed setting part 201d WB characteristic setting part (gain range changing means) 201e Filter part 201f Recording Image generation unit 201g Reproduction image generation unit 202 FL control circuit 203 Reference clock generation circuit 204 Timing control circuit 205 A / D converter 206 Black level correction circuit 207 WB circuit (white balance adjustment means) 208 γ correction circuit 209 Image memory 210 VRAM 211 switch group 212 RTC 213 card I / F 214 communication I / F 3 imaging unit 301 macro zoom lens 302 imaging circuit 303 CCD area sensor (color imaging unit) 304 dimming circuit 305 dimming sensor 30 Focus actuator 307 Signal processing circuit 307a CDS circuit 307b AGC circuit 308 Timing generator 309 Switch group 4 Grip unit 5 Flash 6 UP switch 7 DOWN switch 8 Erase switch 9 Shutter button 10 LCD display unit 11 FL mode setting switch 12 Compression rate setting switch 13 Connection terminal 14 Recording / playback mode setting switch 15 Lid 16 Main switch 17 Memory card

Continued on the front page F term (reference) 5C021 PA17 RB00 RB03 XA03 5C055 BA05 EA02 EA05 GA00 HA14 5C065 AA01 BB02 CC01 DD01 GG15 GG50 5C066 AA01 CA05 EA14 GA01 GA05 GB01 JA01 KA12

Claims (3)

[Claims] 1. A subject light image is photoelectrically converted into image data of three primary color components by a color image pickup means and taken in.
In a camera in which the white balance of a captured image is adjusted by amplifying image data of color components by a predetermined gain within a corresponding allowable gain range by a white balance adjusting unit, a luminance detecting unit that detects luminance of a subject. Gain range changing means for changing the allowable gain range such that the range becomes narrower as the brightness of the subject increases based on the brightness of the subject detected by the brightness detection means. Camera. 2. A subject light image is photoelectrically converted into image data of three primary color components by a color image pickup means and taken in.
Distance detection means for detecting the distance to a subject in a camera in which the white balance of a captured image is adjusted by amplifying image data of color components by a predetermined gain within a corresponding allowable gain range by a white balance adjustment means. And a gain range changing means for changing the allowable gain range based on the distance to the subject detected by the distance detecting means so that the range becomes narrower as the distance to the subject increases. A camera characterized by the following. 3. A subject light image is photoelectrically converted into image data of three primary color components by a color image pickup means and taken in.
In a camera in which the white balance of a captured image is adjusted by amplifying image data of color components by a predetermined gain within a corresponding allowable gain range by a white balance adjusting unit, a luminance detecting unit that detects luminance of a subject. A distance detecting means for detecting a distance to the subject; and a luminance of the subject based on the luminance of the subject and a distance to the subject detected by the luminance detecting means and the distance detecting means. A camera comprising: gain range changing means for changing the allowable gain range so that the range becomes narrower as the size increases.