JP2007053499A - White balance control unit and imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a white balance control unit capable of accurately carrying out correction independently of the transfer efficiency of an imaging element and to provide an imaging apparatus. <P>SOLUTION: A transfer efficiency detecting unit 70 detects the transfer efficiency of a CCD 36. A camera sensitivity detecting unit 72 acquires sensitivity information of the CCD 36. A light source color temperature detection unit 74 acquires color temperature information of a light source calculated by a CPU 10. A drive frequency detection unit 76 acquires a drive pulse frequency of the CCD 36. An enclosure temperature detection unit 78 detects the temperature of an enclosure of a camera 1. A WB integration value correction unit 80 corrects a WB integral value (R/G, B/G) on the basis of the transfer efficiency, the sensitivity, and a driving frequency of the CCD 36, the light source color temperature information, and the enclosure temperature information. An AE/AWB detection circuit 62 calculates color dependent average integral values of the signals by each division area and provides the results to the CPU 10. The CPU 10 discriminates the type of the light source on the basis of the distribution or the like of the R/G and B/G by each division area in the color space to control the gain value (white balance correction value) applied to the R, G, B signals thereby correcting each color signal. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a white balance control device and an imaging device, and more particularly to a technique for performing white balance processing on a color image.

Conventionally, an imaging device (electronic camera, digital camera) using an imaging element using photoelectric conversion such as a CCD (Charge Coupled Device) has been developed. When imaging is performed by an imaging apparatus using a CCD, signal charges are accumulated in each pixel of the CCD according to the exposure time. The signal charge accumulated in each pixel is transferred from the vertical transfer path to the horizontal transfer path and output to the image processing circuit. The signal charges accumulated in each pixel are sequentially transferred through potential wells formed in each transfer element of each transfer path. At this time, since the signal charge remains without being completely transferred to the next transfer element, the signal charge remaining in the transfer element and a signal charge of a different color by the next transfer are mixed to cause color mixing. On the other hand, for example, Patent Document 1 discloses a signal correction device for a distance measuring CCD that corrects distortion of an image signal due to a transfer error and eliminates a distance measurement failure. Further, in Patent Document 2, the total of the vertical transfer remaining amount of each image sensor arranged in the TDI stage direction is obtained in advance from the vertical transfer efficiency of the TDI image sensor, and the output of the TDI image sensor when the sample is imaged by the TDI image sensor. An image processing method for subtracting the sum of the remaining vertical transfer amounts obtained in advance and performing image processing using the subtracted output is disclosed.
JP 7-146139 A JP 2004-295709 A

  By the way, in recent years, the above-described imaging apparatus is provided with a white balance function. When performing white balance, the color information of white or gray is used to estimate the color temperature of the photographing light source and correct the image. However, when pixel-level color mixing occurs as described above, white and gray pixels are mixed, so that white and gray color information serving as a white balance reference is not accurately detected, and accurate white There was a problem that balance correction could not be performed. In addition, color mixture is likely to occur depending on the color temperature of the light source under photographing conditions, which may affect white balance.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a white balance control device and an imaging device capable of accurately performing white balance correction regardless of a change in transfer efficiency of the imaging device. And

  In order to achieve the above object, a white balance control device according to a first aspect includes an integrated value calculating means for calculating an integrated value for white balance adjustment from an image input via an image sensor, and at least a transfer of the image sensor. Detecting means for detecting parameters of the image sensor including efficiency; integrated value correcting means for correcting the integrated value based on the detected parameter; and adjusting white balance based on the corrected integrated value White balance adjusting means.

  According to the white balance control device of the first aspect, it is possible to correct white balance accurately by correcting the integrated value in accordance with the imaging element parameters such as transfer efficiency.

  A white balance control device according to a second aspect is the white balance control device according to the first aspect, wherein the integrated value calculating means calculates a ratio R / G value and a B / G value of the integrated value of the G signal to the integrated value of the R and B signals. The integrated value correction means corrects the R / G value and the B / G value by calculating at least one of the integrated values of R, B, and G. Claim 2 limits the method of correcting the integrated values (R / G value and B / G value).

  According to a third aspect of the present invention, the white balance control device according to the first or second aspect further includes a light source information acquiring unit that acquires light source information under a shooting condition based on the calculated integrated value, and the integrated value correcting unit includes: The color information is corrected based on the light source information.

  According to the white balance control device of the third aspect, the white balance can be accurately corrected by correcting the color information based on the light source information (for example, the color temperature of the light source).

  According to a fourth aspect of the present invention, there is provided a white balance control device comprising: integrated value calculating means for calculating an integrated value for white balance adjustment from an image input via an image sensor; and under a shooting condition based on the calculated integrated value. A light source evaluation value calculating means for calculating a light source evaluation value for determining a light source; a detecting means for detecting a parameter of the image sensor including at least a transfer efficiency of the image sensor; and based on the detected parameter. A light source evaluation value correcting unit that corrects a light source evaluation value and a white balance adjusting unit that adjusts a white balance based on the corrected light source evaluation value are provided.

  According to the white balance control device of the fourth aspect, the light source evaluation value is corrected in accordance with the parameters of the image sensor, whereby the light source under the shooting condition can be accurately determined, and accurate white balance correction can be performed. It can be carried out.

  According to a fifth aspect of the present invention, in the white balance control device according to the fourth aspect, the light source evaluation value correcting unit calculates a difference between integrated values of the G signal and the R signal. The fifth aspect limits the types of light source evaluation values.

  A white balance control device according to a sixth aspect of the present invention is the white balance control device according to the fourth or fifth aspect, further comprising light source information acquisition means for acquiring light source information under a photographing condition based on the calculated integrated value, and the light source evaluation value correction means. Is characterized in that the light source evaluation value is corrected based on the light source information.

  According to the white balance control device of the sixth aspect, the white balance can be accurately corrected by correcting the light source evaluation value based on the light source information (for example, the color temperature of the light source).

  A white balance control device according to claim 7 is an integrated value calculating means for calculating an integrated value for white balance adjustment from an image input via an image sensor, and acquires gray color information from the calculated integrated value. Gray acquisition means, detection means for detecting parameters of the image sensor including at least the transfer efficiency of the image sensor, gray correction means for correcting the color information of the gray based on the detected parameters, White balance adjusting means for adjusting white balance based on the acquired gray color information.

  According to the white balance control device of the seventh aspect, it is possible to perform accurate white balance correction by correcting gray color information serving as a reference for white balance in accordance with imaging element parameters such as transfer efficiency. .

  The white balance control device according to an eighth aspect of the present invention is the white balance control device according to the seventh aspect, wherein the integrated value calculating means calculates a ratio R / G value and a B / G value of the integrated value of the G signal to the integrated value of the R and B signals. The gray correction unit corrects the R / G value and the B / G value by performing an operation on at least one of R, B, and G values of the gray color information.

  According to the white balance control device of the eighth aspect, the method for correcting the color information (R / G value and B / G value) is limited.

  A white balance control device according to claim 9 further comprises light source information acquisition means for acquiring light source information under shooting conditions based on the calculated integrated value in claim 7 or 8, wherein the gray correction means comprises: The light source evaluation value is corrected based on the light source information.

  According to the white balance control device of the ninth aspect, the white balance correction can be performed accurately by correcting the gray color information based on the light source information (for example, the color temperature of the light source).

  A white balance control device according to a tenth aspect is the invention according to any one of the first to ninth aspects, wherein the parameters of the image sensor include at least one of sensitivity, drive frequency, and temperature of the image sensor. A tenth aspect of the present invention limits the parameters of the imaging device according to the first to ninth aspects.

  An imaging apparatus according to an eleventh aspect includes the white balance control apparatus according to any one of the first to tenth aspects.

  According to the present invention, the WB integrated value, the light source evaluation value, or the gray color information is corrected by the image sensor parameters such as the transfer efficiency, sensitivity, drive frequency, or temperature of the image sensor, and the color temperature of the light source. Accurate white balance correction can be performed.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a white balance control device according to the present invention and an imaging device including the white balance control device according to the present invention will be described with reference to the accompanying drawings. In the following description, an imaging device (digital camera) to which the white balance control device of the present invention is applied will be described as an example. However, the present invention is not limited to a mobile phone, a personal digital assistant (PDA), a PC equipped with the imaging device. It can also be applied to cameras and the like.

  FIG. 1 is a block diagram illustrating a main configuration of an imaging apparatus including a white balance control apparatus according to the first embodiment of the present invention. An imaging apparatus 1 (denoted as camera 1 in the following description) shown in FIG. 1 is a digital camera having functions for recording and reproducing still images and moving images. The operation of the entire camera 1 is a central processing unit (CPU). 10 for overall control. The CPU 10 functions as a control means for controlling the camera system according to a predetermined program, and performs various calculations such as automatic exposure (AE) calculation, automatic focus adjustment (AF) calculation, and white balance (WB) adjustment calculation. Functions as a means. The power supply circuit 12 supplies power to each block of the camera system.

  A ROM (Read Only Memory) 16 and an EEPROM (Electronically Erasable and Programmable Read Only Memory) 18 are connected to the CPU 10 via a bus 14. The ROM 16 stores programs executed by the CPU 10, various data necessary for control, and the like, and the EEPROM 18 stores CCD pixel defect information, various constants / information related to camera operation, and the like.

  A memory (SDRAM, Synchronous Dynamic Random Access Memory) 20 is used as a program development area and a calculation work area for the CPU 10, and is also used as a temporary storage area for image data and audio data. A video random access memory (VRAM) 22 is a temporary storage memory dedicated to image data, and includes an A area 22A and a B area 22B. The memory 20 and the VRAM 22 can be shared.

  The camera 1 is provided with an operation switch group 24 such as a mode selection switch, a shooting button, a menu / OK key, a cross key, and a cancel key. Signals from these various operation switches are input to the CPU 10, and the CPU 10 controls each circuit of the camera 1 based on the input signals. For example, lens drive control, shooting operation control, image processing control, and image data recording / reproduction. Control and display control of the image display device (liquid crystal monitor) 26 are performed.

  The mode selection switch is an operation means for switching between the shooting mode and the playback mode. The shooting button is an operation button for inputting an instruction to start shooting, and includes a two-stroke switch having an S1 switch that is turned on when half-pressed and an S2 switch that is turned on when fully pressed. The menu / OK key is an operation having both a function as a menu button for instructing to display a menu on the screen of the image display device 26 and a function as an OK button for instructing confirmation and execution of selection contents. Key. The cross key is an operation unit for inputting instructions in four directions, up, down, left, and right, and functions as a button (cursor moving operation means) for selecting an item from the menu screen or instructing selection of various setting items from each menu. To do. The up / down key of the cross key functions as a zoom switch at the time of shooting or a playback zoom switch at the time of playback, and the left / right key functions as a frame advance (forward / reverse feed) button in the playback mode. The cancel key is used to delete a desired target such as a selection item, cancel an instruction content, or return to the previous operation state.

  The image display device 26 is composed of a liquid crystal monitor capable of color display. An image display device 26 (referred to as a liquid crystal monitor 26 in the following description) can be used as an electronic viewfinder for checking the angle of view at the time of shooting, and is used as means for reproducing and displaying recorded images. The liquid crystal monitor 26 is also used as a user interface display screen, and displays information such as menu information, selection items, and setting contents as necessary. Instead of the liquid crystal monitor, other types of display devices such as organic EL (electro-luminescence) can be used.

  The camera 1 has a media socket (media mounting portion) 28, and a recording medium 30 can be mounted on the media socket 28. The form of the recording medium 30 is not particularly limited, and various media such as a semiconductor memory card represented by xD-PictureCard (trademark) and smart media (trademark), a portable small hard disk, a magnetic disk, an optical disk, and a magneto-optical disk can be used. Can be used. The media controller 32 performs necessary signal conversion in order to transfer input / output signals suitable for the recording medium 30 mounted in the media socket 28.

  The camera 1 also includes an external connection interface (I / F) unit 34 as communication means for connecting to a personal computer or other external devices. The camera 1 can exchange data with the external device by connecting the camera 1 and the external device using a USB cable (not shown). Of course, the communication method is not limited to USB, and IEEE1394, Bluetooth, and other communication methods may be applied.

  Next, the shooting function of the camera 1 will be described. When the shooting mode is selected by the mode selection switch, power is supplied to the imaging unit including the color CCD solid-state imaging device 36 (hereinafter referred to as CCD 36), and the camera is ready for shooting.

  The lens unit 38 is an optical unit including a photographing lens 44 including a focus lens 40 and a zoom lens 42, and a diaphragm / mechanical shutter 46. Focusing of the photographic lens 44 is performed by moving the focus lens 40 by the focus motor 40A, and zooming is performed by moving the zoom lens 42 by the zoom motor 42A. The focus motor 40A and the zoom motor 42A are driven and controlled by the focus motor driver 40B and the zoom motor driver 42B, respectively. The CPU 10 controls the focus motor driver 40B and the zoom motor driver 42B by outputting control signals.

  The diaphragm 46 is a so-called turret-type diaphragm, and changes the diaphragm value (F value) by rotating a turret plate in which diaphragm holes of F2.8 to F8 are formed. The diaphragm 46 is driven by an iris motor 46A. The iris motor 46A is driven and controlled by an iris motor driver 46B. The CPU 10 controls the iris motor driver 46B by outputting a control signal.

  The light that has passed through the lens unit 38 forms an image on the light receiving surface of the CCD 36. A large number of photodiodes (light receiving elements) are two-dimensionally arranged on the light receiving surface of the CCD 36, and red (R), green (G), and blue (B) primary color filters corresponding to each photodiode. They are arranged in a predetermined arrangement structure (Bayer, G stripe, etc.). The CCD 36 has an electronic shutter function for controlling the charge accumulation time (shutter speed) of each photodiode. The CPU 10 controls the charge accumulation time in the CCD 36 via a timing generator (TG) 48.

  The subject image formed on the light receiving surface of the CCD 36 is converted into signal charges of an amount corresponding to the amount of incident light by each photodiode. The signal charge accumulated in each photodiode is sequentially read out as a voltage signal (image signal) corresponding to the signal charge based on a drive pulse given from the TG 48 in accordance with a command from the CPU 10.

  The signal output from the CCD 36 is sent to an analog processing unit (CDS / AMP) 50, where the R, G, B signals for each pixel are sampled and held (correlated double sampling processing), amplified, and then A / It is added to the D converter 52. The dot sequential R, G, B signals converted into digital signals by the A / D converter 52 are stored in the memory 20 via the image input controller 54.

  The image signal processing circuit 56 processes the R, G, and B signals stored in the memory 20 in accordance with instructions from the CPU 10. That is, the image signal processing circuit 56 includes a synchronization circuit (a processing circuit that converts a color signal into a simultaneous expression by interpolating a spatial shift of the color signal associated with the color filter array of the single CCD), a white balance correction circuit, It functions as an image processing means including a gamma correction circuit, a contour correction circuit, a luminance / color difference signal generation circuit, etc., and performs predetermined signal processing using the memory 20 in accordance with commands from the CPU 10.

  The RGB image data input to the image signal processing circuit 56 is converted into a luminance signal (Y signal) and a color difference signal (Cr, Cb signal) by the image signal processing circuit 56, and predetermined processing such as gamma correction is performed. Applied. The image data processed by the image signal processing circuit 56 is stored in the VRAM 22.

  When the captured image is output to the liquid crystal monitor 26, the image data is read from the VRAM 22 and sent to the video encoder 58 via the bus 14. The video encoder 58 converts the input image data into a predetermined display signal (for example, an NTSC color composite image signal) and outputs the converted signal to the liquid crystal monitor 26.

  With the image signal output from the CCD 36, image data representing an image for one frame is rewritten alternately in the A area 22A and the B area 22B of the VRAM 22. Of the A area 22A and B area 22B of the VRAM 22, the written image data is read from an area other than the area where the image data is rewritten. In this way, the image data in the VRAM 22 is periodically rewritten, and an image signal generated from the image data is supplied to the liquid crystal monitor 26, whereby the image being captured is displayed on the liquid crystal monitor 26 in real time. . The photographer can check the shooting angle of view from the video (through movie image) displayed on the liquid crystal monitor 26.

  When the shooting button is pressed halfway and S1 is turned on, the camera 1 starts AE and AF processing. That is, the image signal output from the CCD 36 is input to the AF detection circuit 60 and the AE / AWB detection circuit 62 via the image input controller 54 after A / D conversion.

  The AE / AWB detection circuit 62 includes a circuit that divides one screen into a plurality of areas (for example, 8 × 8 or 16 × 16) and integrates RGB signals for each divided area, and provides the integrated value to the CPU 10. . The CPU 10 detects the brightness of the subject (subject brightness) based on the integrated value obtained from the AE / AWB detection circuit 62, and calculates an exposure value (shooting EV value) suitable for shooting. According to the obtained exposure value and a predetermined program diagram, the aperture value and the shutter speed are determined, and the CPU 10 controls the electronic shutter and iris of the CCD 36 to obtain an appropriate exposure amount.

  The AE / AWB detection circuit 62 calculates an average integrated value for each color of the RGB signals for each divided area during automatic white balance adjustment, and provides the calculation result to the CPU 10. The CPU 10 obtains an integrated value of R, an integrated value of B, and an integrated value of G, obtains a ratio of R / G and B / G for each divided area, and calculates R / G and R / G of the values of B / G. The light source type is determined based on the distribution in the color space of the G, B / G axis coordinates, and the gain value (white balance correction value) for the R, G, B signals of the white balance adjustment circuit according to the determined light source type. To correct the signal of each color channel. Details of the white balance adjustment will be described later.

  For example, contrast AF that moves the focus lens 40 so that the high-frequency component of the G signal of the image signal is maximized is applied to the AF control in the camera 1. That is, the AF detection circuit 60 cuts out a signal in a focus target area set in advance in a high-pass filter that passes only a high-frequency component of the G signal, an absolute value processing unit, and a screen (for example, the center of the screen). An area extraction unit and an integration unit that integrates absolute value data in the AF area are configured.

  The integrated value data obtained by the AF detection circuit 60 is notified to the CPU 10. The CPU 10 calculates a focus evaluation value (AF evaluation value) at a plurality of AF detection points while moving the focus lens 40 by controlling the focus motor driver 40B, and sets a lens position where the evaluation value is a maximum as a focus position. decide. Then, the CPU 10 controls the focus motor driver 40B so as to move the focus lens 40 to the obtained in-focus position. The calculation of the AF evaluation value is not limited to a mode using the G signal, and a luminance signal (Y signal) may be used.

  The shooting button is pressed halfway, AE / AF processing is performed when S1 is turned on, the shooting button is fully pressed, and the shooting operation for recording starts when S2 is turned on. The image data acquired in response to S2 ON is converted into a luminance / color difference signal (Y / C signal) in the image signal processing circuit 56, subjected to predetermined processing such as gamma correction, and then stored in the memory 20. The

  The Y / C signal stored in the memory 20 is compressed according to a predetermined format by the compression / decompression circuit 64 and then recorded on the recording medium 30 via the media controller 32. For example, a still image is recorded in JPEG (Joint Photographic Experts Group) format.

  When the playback mode is selected by the mode selection switch, the compressed data of the last image file (last recorded file) recorded on the recording medium 30 is read. When the file related to the last recording is a still image file, the read image compressed data is decompressed into an uncompressed YC signal via the compression / decompression circuit 64, and then via the image signal processing circuit 56 and the video encoder 58. Are converted into display signals and then output to the liquid crystal monitor 26. As a result, the image content of the file is displayed on the screen of the liquid crystal monitor 26.

  During single-frame playback of still images (including playback of the first frame of a movie), the file to be played can be switched (forward / reverse frame advance) by operating the right or left key of the four-way controller. it can. The image file at the frame-advanced position is read from the recording medium 30, and still images and moving images are reproduced and displayed on the liquid crystal monitor 26 in the same manner as described above.

  When an external display such as a personal computer or a television is connected to the camera 1 via the video input / output terminal 66 in the playback mode, the image data recorded on the recording medium 30 is output by the video output circuit 68. It is processed and displayed on this external display.

  The camera 1 of the present embodiment further includes a transfer efficiency detection unit 70, a camera sensitivity detection unit 72, a light source color temperature detection unit 74, a drive frequency detection unit 76, a case temperature detection unit 78, and a WB integrated value correction unit 80. .

  The transfer efficiency detection unit 70 is a device that detects the transfer efficiency of the CCD 36. Here, a method for calculating the transfer efficiency will be described with reference to FIG. FIG. 2 is a diagram schematically showing a charge transfer path in the CCD 36. As shown in FIG. 2, the CCD 36 forms an image of light that has entered through the photographing lens 30, and an effective pixel area that is used for capturing an image and an invalid area around the effective pixel area that is not used for capturing an image. Are divided into various optical black (OB) regions.

  When a subject (for example, a monochrome chart) is imaged by the camera 1, charges are accumulated in each pixel of the CCD 36. This charge is vertically transferred through the horizontal transfer path 92 after one pixel in the vertical direction is vertically transferred through the vertical transfer path 90. This charge is converted into a voltage by the charge-voltage converter 94 and output to the analog signal processing circuit 42. By repeating this for the number of pixels in the vertical direction, the charges of all the pixels of the CCD 36 are read out.

  The transfer efficiency detection unit 70 acquires the voltage value of one pixel 96B on the OB area side in the boundary area where the effective pixel area changes to the OB area. The voltage value of one pixel 96B on the OB region side corresponds to the amount of charge left during transfer of one pixel 96A on the effective pixel region side. The transfer efficiency detector 70 calculates the transfer efficiency of the CCD 36 based on the voltage values of the pixels 96A and 96B.

  In the present embodiment, the transfer efficiency is not calculated by the transfer efficiency detection unit 70, but the transfer efficiency value is stored in the memory 20 or the like in advance, and the transfer efficiency detection unit 70 acquires the transfer efficiency value. Also good. For example, the memory 20 may store the transfer efficiency for each elapsed time after the power is turned on.

  Returning to the description of FIG. The camera sensitivity detector 72 acquires sensitivity (ISO) information of the CCD 36 set at the time of imaging. The light source color temperature detection unit 74 acquires the color temperature information of the light source calculated by the CPU 10. The drive frequency detector 76 acquires the frequency of the drive pulse output from the TG 48 (drive frequency information of the CCD 36). The case temperature detection unit 78 detects the temperature of the case of the camera 1. In this embodiment, instead of the temperature of the housing of the camera 1, the temperature of the block that processes the analog signal including the CCD 36, the analog processing unit 50, and the A / D converter 52 may be detected. .

  The WB integrated value correction unit 80 is based on the transfer efficiency, sensitivity, drive frequency, light source color temperature information, and housing temperature detected in the above, and white balance (WB) integrated value data (R / G, B / G) is corrected.

  Next, an auto white balance adjustment method according to the present invention will be described. FIG. 3 is a flowchart showing the flow of white balance adjustment processing according to an embodiment of the present invention.

  First, when the shooting button is pressed, the subject is shot. The R, G, and B signals obtained from the CCD 36 at the time of photographing are temporarily stored in the memory 20. The CPU 10 uses the R, G, and B signals stored in the memory 20 to calculate an average integrated value for each color of the RGB signals for each of 256 divided areas in which one screen is divided into 16 × 16, The ratio of the average integrated values of R, G, and B, that is, the ratio of R / G and B / G (WB integrated value) is calculated for each divided area (step S10). The integrated value for WB is corrected by the integrated value correcting unit 80 for WB. A method for correcting the integrated value for WB will be described later.

  The color information for each of the 256 divided areas calculated in this way is distributed in the color space of the R / G and B / G axis coordinates shown in FIG. 4 based on the R / G and B / G values. Can be represented as 256 points.

  Next, the color temperature of the light source is calculated (step S12). The CPU 10 is a set of color information that is close to each other out of 256 pieces of color information distributed in the color space of the R / G and B / G axis coordinates (in the following description, described as “catamari”). The position of the center of gravity is calculated. Then, the color temperature of the color information indicated by the position of the center of gravity of the catamari is detected. The reason why the color information is catalyzed is that the subject is illuminated by a light source having a certain color temperature. Accordingly, a light source type having color information that is most approximate to the color information of the center of gravity position of the catamaria (for example, the blue sky, shade 1 to 4, shown in FIG. 5, daylight color 1 to 4, sunny, day white 1, 2, white 1, 2 , Warm white 1-4, tungsten 1-4, low tungsten, etc.) can be automatically determined.

  Next, the color information after the predetermined color adaptation of the color information on the black body locus corresponding to the color temperature detected in step S12 is set as a target value, and the white balance gain is calculated (step S14). In step S14, color information after chromatic adaptation is set as a target value in order to obtain “original appearance of human” by chromatic adaptation, not the color information itself on the black body locus corresponding to the detected color temperature. The color information after color adaptation at this time can be a value predicted by a color adaptation prediction formula of CIE (International Commission on Illumination), for example.

Then, if the coordinates of the center of gravity position of the R / G, B / G coordinate system are (Xi, Yi) and the coordinates of the target value are (Xj, Yj), the coordinates (Xi, Yi) are the coordinates (Xj, Yj). ) To obtain a white balance gain (WB gain). Now, assuming that the WB gains to be obtained are g _r i and g _b i, g _r i and g _b i can be expressed by the following equations: g _r i = Xj / Xi and g _b i = Yj / Yi.

The R, G, and B gain values (WB correction values) for the R, G, and B signals stored in the memory 20 of FIG. 1 are obtained from the WB gains g _r i and g _b i obtained as described above. The R and B gain values to be added to the R and B signals can be obtained by multiplying the WB gains g _r i and g _b i by the required gain values to be added to the G signal. When the required gain value to be applied to the G signal is 1, the WB gains g _r i and g _b i are the R and B gain values to be applied to the R and B signals as they are.

  Then, the R, G, B signals stored in the memory 20 are corrected by the R, G, B gain values (WB correction values). Thereby, white balance adjustment is performed (step S16).

  In this way, by adjusting the white balance by setting the color from the “light source appearance” to full adaptation as the target value, for example, a white balance adjustment that removes redness a little with a tungsten light source is performed, and it is refreshing. It becomes a natural hue.

  In this embodiment, the color information related to the light source type is obtained from the barycentric position of the catamari in the color space in which the color information of a plurality of divided areas is distributed. However, the present invention is not limited to this, and R / G, B / G color space, blue sky as shown in FIG. 5, shade 1-4, daylight color 1-4, clear, day white 1, 2, white 1, 2, warm white 1-4, tungsten 1-4 Set a detection frame indicating the range of color distribution corresponding to the light source type such as low tungsten, and obtain the number of divided areas where the color information enters each detection frame based on the color information for each divided area, and the luminance of the subject The light source type may be determined based on the level and the number of divided areas included in the detection frame, and the center coordinates of the detection frame corresponding to the light source type may be obtained as color information related to the light source type under the shooting condition.

  Next, a method for correcting the integrated value for WB will be described. FIG. 6 is a graph showing a method for correcting the integrated value of white balance. In FIG. 6, the horizontal axis represents the transfer efficiency of the CCD 36, and the vertical axis represents the integrated value for WB. As indicated by the broken lines L1 and L2 in FIG. 6, when the transfer efficiency of the CCD 36 decreases, pixel mixing occurs at an analog level, so that the integrated value for WB deviates from the case where the transfer efficiency is 100%. In this embodiment, the change in the integrated value for WB is measured in advance for each transfer efficiency of the CCD 36. Based on this measurement result, the WB integrated value correction coefficient 1 for correcting the deviation of the WB integrated value is calculated for each transfer efficiency. This WB integrated value correction coefficient 1 is calculated for each integrated value R / G and B / G. A table (WB integrated value correction coefficient 1 table) in which the relationship between the transfer efficiency and the WB integrated value correction coefficient 1 is recorded is stored in the memory 20.

  FIG. 7 is a graph illustrating a part of the WB integrated value correction coefficient 1 table showing the relationship between the transfer efficiency and the WB integrated value correction coefficient 1. As indicated by the solid line L3 in FIG. 7, the value of the WB integrated value correction coefficient 1 multiplied by the WB integrated value R / G increases as the transfer efficiency decreases. On the other hand, as indicated by a solid line L4 in FIG. 7, the value of the WB integrated value correction coefficient 1 multiplied by the WB integrated value B / G decreases as the transfer efficiency decreases.

  The WB integrated value correcting unit 72 corresponds to the WB integrated values R / G and B / G from the WB integrated value correction coefficient 1 table according to the transfer efficiency of the CCD 36 detected by the transfer efficiency detecting unit 70. The WB integrated value correction coefficient 1 to be selected is selected and multiplied by the WB integrated value. As a result, as shown by solid lines L1 ′ and L2 ′ in FIG. 6, the WB integrated values R / G and B / G are corrected so as to approach the values when the transfer efficiency is 100%.

  Also, the integrated value correction coefficient for WB is set in advance for the sensitivity of the CCD 36, the drive frequency, the color temperature of the light source, and the temperature of the housing. The WB integrated value correction unit 72 selects the corresponding WB integrated value correction coefficient based on the sensitivity of the CCD 36 detected in the above, the drive frequency, the color temperature of the light source, and the temperature of the casing, and the integrated value for WB. Multiply with Thereby, it is possible to correct a deviation in the integrated value for WB due to pixel mixing caused by changes in the transfer efficiency and sensitivity of the CCD 36, the drive frequency, the color temperature of the light source, and the temperature of the housing. In the following description, the WB integrated value correction coefficients set corresponding to the sensitivity of the CCD 36, the drive frequency, the color temperature of the light source, and the temperature of the housing are described as WB integrated value correction coefficients 2 to 5, respectively. .

  The WB integrated value correction coefficient is calculated for each of the two values of the WB integrated values R / G and B / G. For example, at least one of the three values R, G, and B is used. A coefficient to be multiplied by one value may be set.

  Next, the flow of the WB integrated value correction process will be described with reference to the flowchart of FIG. FIG. 8 is a flowchart showing the flow of the correction process of the integrated value for WB.

  First, the transfer efficiency, camera sensitivity, drive frequency, and light source color of the CCD 36 are determined by the transfer efficiency detector 70, camera sensitivity detector 72, drive frequency detector 76, light source color temperature detector 74, and housing temperature detector 78. The temperature and the housing temperature are acquired (step S30). Next, based on the transfer efficiency, camera sensitivity, drive frequency, color temperature of the light source, and housing temperature detected in step S30, the WB integrated value correction to be applied to the WB integrated value R / G and B / G is corrected. Two coefficients 1 to 5 are acquired (step S32 to step S40). Then, as shown in the following formula (1), the WB integrated values R / G and B / G are multiplied by the WB integrated value correction coefficients 1 to 5 to correct the WB integrated values R / G and B / G. (Step S42).

[Corrected WB integrated value (R / G or B / G)] = [WB integrated value (R / G or B / G)] × (WB integrated value correction coefficient 1) × (WB integrated value) Correction coefficient 2) × (WB integrated value correction coefficient 3) × (WB integrated value correction coefficient 4) × (WB integrated value correction coefficient 5) (1)
According to the present embodiment, it is possible to correct the deviation of the integrated value for WB due to pixel mixing caused by the change in transfer efficiency and sensitivity of the CCD 36, the driving frequency, the color temperature of the light source, and the temperature of the housing, and therefore an accurate white Balance control can be performed.

  In the present embodiment, the WB integrated values R / G and B / G are multiplied by the WB integrated value correction coefficients 1 to 5, but the present invention is not limited to this. As shown in Equation (2), the correction value of the WB integrated value corresponding to the transfer efficiency and sensitivity of the CCD 36, the drive frequency, the color temperature of the light source, and the temperature of the housing (respectively, the integrated value correction values 1 to 5 for the WB are ) May be added to the integrated values R / G and B / G for WB. As a method for correcting the integrated value for WB, either addition, subtraction, multiplication or division may be used.

[Corrected WB integrated value (R / G or B / G)] = [WB integrated value (R / G or B / G)] + (WB integrated value correction value 1) + (WB integrated value) Correction value 2) + (WB integrated value correction value 3) + (WB integrated value correction value 4) + (WB integrated value correction value 5) (2)
Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 9 is a block diagram illustrating a main configuration of an imaging apparatus including a white balance control apparatus according to the second embodiment of the present invention. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 9, the imaging apparatus (camera) 1 of the present embodiment includes a light source evaluation value correction unit 82 and a light source determination unit 84. The light source evaluation value correction unit 82 includes the transfer efficiency and sensitivity of the CCD 36 detected by the transfer efficiency detection unit 70, the camera sensitivity detection unit 72, the drive frequency detection unit 76, the light source color temperature detection unit 74, and the housing temperature detection unit 78. The light source evaluation value is corrected based on the drive frequency, the color temperature information of the light source, and the housing temperature. Here, the light source evaluation value is, for example, a difference between integrated values of R and B (B−R) or (R−B). In addition to the above, as the light source evaluation value, for example, R / G and B / G and color difference signals (BY, RY, and GY) can be used. The light source determination unit 84 determines the type of light source based on the light source evaluation value corrected by the light source evaluation value correction unit 98.

  FIG. 10 is a graph showing a method for correcting the light source evaluation value. In FIG. 10, the horizontal axis represents the light source evaluation value of the CCD 36, and the vertical axis represents the brightness. As shown in FIG. 10, when the transfer efficiency of the CCD 36 is lowered, pixel mixing occurs at an analog level, so that the light source evaluation value is deviated from the case where the transfer efficiency is 100%.

  In this embodiment, the change in the light source evaluation value is measured in advance for each transfer efficiency of the CCD 36. Based on this measurement result, a light source evaluation value correction coefficient 1 for correcting the deviation of the light source evaluation value is calculated for each transfer efficiency. A table (a light source evaluation value correction coefficient 1 table) in which the relationship between the transfer efficiency and the light source evaluation value correction coefficient 1 is recorded is stored in the memory 20.

  FIG. 11 is a graph illustrating a part of the light source evaluation value correction coefficient 1 table showing the relationship between the transfer efficiency and the light source evaluation value correction coefficient 1. In the example shown in FIG. 10, the light source evaluation value decreases due to a decrease in the transfer efficiency of the CCD 36, and the fluorescent lamp light source may be erroneously recognized as a tungsten light source. Therefore, as shown in FIG. 11, the value of the light source evaluation value correction coefficient 1 multiplied by the light source evaluation value increases as the transfer efficiency decreases.

  The light source evaluation value correction unit 82 selects the light source evaluation value correction coefficient 1 from the light source evaluation value correction coefficient 1 table according to the transfer efficiency of the CCD 36 detected by the transfer efficiency detection unit 70 and multiplies the light source evaluation value by the light source evaluation value. To do. Thereby, as shown in FIG. 10, the light source evaluation value is corrected so as to approach the value when the transfer efficiency is 100%.

  The light source evaluation value correction coefficient is also set in advance for the sensitivity of the CCD 36, the driving frequency, the color temperature of the light source, and the temperature of the housing. The light source evaluation value correction unit 82 selects a corresponding light source evaluation value correction coefficient based on the sensitivity of the CCD 36 detected above, the drive frequency, the color temperature of the light source, and the temperature of the housing, and multiplies it with the light source evaluation value. . Thereby, it is possible to correct the deviation of the light source evaluation value due to the pixel mixing caused by the change in the transfer efficiency and sensitivity of the CCD 36, the driving frequency, the color temperature of the light source, and the temperature of the housing. In the following description, the light source evaluation value correction coefficients set corresponding to the sensitivity of the CCD 36, the driving frequency, the color temperature of the light source, and the temperature of the housing are described as light source evaluation value correction coefficients 2 to 5, respectively.

  Next, the flow of light source evaluation value correction processing will be described with reference to the flowchart of FIG. FIG. 12 is a flowchart showing the flow of the light source evaluation value correction process.

  First, the transfer efficiency, camera sensitivity, drive frequency, and light source color of the CCD 36 are determined by the transfer efficiency detector 70, camera sensitivity detector 72, drive frequency detector 76, light source color temperature detector 74, and housing temperature detector 78. The temperature and the housing temperature are acquired (step S50). Next, light source evaluation value correction coefficients 1 to 5 are acquired based on the transfer efficiency, camera sensitivity, drive frequency, color temperature of the light source, and housing temperature detected in step S50 (steps S52 to S60). ). Then, as shown in the following formula (3), the light source evaluation value is multiplied by the light source evaluation value correction coefficients 1 to 5 to correct the light source evaluation value (step S62).

(Corrected light source evaluation value) = (light source evaluation value) × (light source evaluation value correction coefficient 1) × (light source evaluation value correction coefficient 2) × (light source evaluation value correction coefficient 3) × (light source evaluation value correction coefficient 4) × (Light source evaluation value correction coefficient 5) (3)
According to the present embodiment, it is possible to correct the deviation of the light source evaluation value due to the pixel mixture caused by the change in the transfer efficiency and sensitivity of the CCD 36, the driving frequency, the color temperature of the light source, and the temperature of the housing, and therefore accurate light source determination Therefore, accurate white balance control can be performed.

  In the present embodiment, the light source evaluation value is multiplied by the light source evaluation value correction coefficients 1 to 5, but the present invention is not limited to this. For example, as shown in the following equation (4): The correction value of the light source evaluation value (respectively, the light source evaluation value correction values 1 to 5) corresponding to the transfer efficiency and sensitivity of the CCD 36, the driving frequency, the color temperature of the light source, and the temperature of the housing may be added to the light source evaluation value. Good. As a method for correcting the light source evaluation value, either addition, subtraction, multiplication or division may be used.

(Corrected light source evaluation value) = (light source evaluation value) + (light source evaluation value correction value 1) + (light source evaluation value correction value 2) + (light source evaluation value correction value 3) + (light source evaluation value correction value 4) + (Light source evaluation value correction value 5) (4)
Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 13 is a block diagram illustrating a main configuration of an imaging apparatus including a white balance control apparatus according to the third embodiment of the present invention. In the following description, the same components as those in the first and second embodiments are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 13, the imaging apparatus (camera) 1 of this embodiment includes a target coordinate correction unit 86 and a target coordinate determination unit 88. The target coordinate correction unit 86 includes the transfer efficiency and sensitivity of the CCD 36 detected by the transfer efficiency detection unit 70, the camera sensitivity detection unit 72, the drive frequency detection unit 76, the light source color temperature detection unit 74, and the housing temperature detection unit 78. The R / G and B / G color coordinates are corrected based on the drive frequency, the light source color temperature information, and the housing temperature. Based on the R / G, B / G color coordinates corrected by the target coordinate correcting unit 86, the target coordinate determining unit 88 is a gray coordinate (R / G, B / G) = (white balance reference). 1,1) is determined.

  FIG. 14 is a graph showing a target coordinate correction method. In FIG. 14, the horizontal axis represents the transfer efficiency of the CCD 36, and the vertical axis represents gray coordinates (R / G, B / G). As shown in FIG. 14, when the transfer efficiency is 100%, coordinates (R / G, B / G) = (1, 1) are set as gray target coordinates. However, when the transfer efficiency of the CCD 36 is lowered, pixel mixing occurs at an analog level, so that the target coordinates are shifted as compared with the case where the transfer efficiency is 100%.

  In this embodiment, the change in target coordinates is measured in advance for each transfer efficiency of the CCD 36. Based on this measurement result, a gray correction coefficient 1 for correcting the deviation of the target coordinates is calculated for each transfer efficiency. A table (gray correction coefficient 1 table) in which the relationship between the transfer efficiency and the gray correction coefficient 1 is recorded is stored in the memory 20.

  FIG. 15 is a graph illustrating a part of the gray correction coefficient 1 table showing the relationship between the transfer efficiency and the gray correction coefficient 1. In the example shown in FIG. 14, the target coordinate B / G (solid line L5) is increased and the target coordinate R / G (solid line L6) is decreased due to a decrease in the transfer efficiency of the CCD 36. Therefore, as indicated by the solid line L7 in FIG. 15, the value of the gray correction coefficient 1 multiplied by the target coordinate B / G decreases as the transfer efficiency decreases. On the other hand, as indicated by the solid line L8 in FIG. 15, the value of the gray correction coefficient 1 multiplied by the target coordinate R / G increases as the transfer efficiency decreases.

  The target coordinate correction unit 86 selects the gray correction coefficient 1 from the gray correction coefficient 1 table according to the transfer efficiency of the CCD 36 detected by the transfer efficiency detection unit 70, and the corresponding CPU 10 divides the image in the image. Multiply with the R / G coordinates and B / G coordinates calculated for each region. As a result, as shown by solid lines L5 ′ and L6 ′ in FIG. 14, the target coordinates R / G and the target coordinates R / G and the values (R / G, B / G) = (1, 1) when the transfer efficiency is 100% are approached. B / G is corrected.

  In FIG. 14, the solid lines L5 ′ and L6 ′ indicating the corrected target coordinates are shown apart from each other for easy viewing, but actually, the solid lines L5 ′ and L6 ′ are both of the G ratio. The correction is preferably made so that the value is a straight line of 1.0.

  Also, gray correction coefficients are set in advance for the sensitivity of the CCD 36, the drive frequency, the color temperature of the light source, and the temperature of the housing. The coordinate correction unit 86 selects the corresponding gray correction coefficient based on the sensitivity of the CCD 36 detected in the above, the drive frequency, the color temperature of the light source, and the temperature of the casing, and selects the R / G coordinate and the B / G coordinate. Multiply. Thereby, it is possible to correct a shift in target coordinates due to pixel mixing caused by a change in transfer efficiency, sensitivity, drive frequency, light source color temperature, and housing temperature of the CCD 36. In the following description, the gray correction coefficients set corresponding to the sensitivity of the CCD 36, the drive frequency, the color temperature of the light source, and the temperature of the housing are described as gray correction coefficients 2 to 5, respectively.

  Next, the flow of target coordinate correction processing will be described with reference to the flowchart of FIG. FIG. 16 is a flowchart showing a flow of target coordinate correction processing.

  First, the transfer efficiency, camera sensitivity, drive frequency, and light source color of the CCD 36 are determined by the transfer efficiency detector 70, camera sensitivity detector 72, drive frequency detector 76, light source color temperature detector 74, and housing temperature detector 78. The temperature and the housing temperature are acquired (step S70). Next, based on the transfer efficiency, camera sensitivity, drive frequency, color temperature of the light source, and housing temperature detected in step S70, the gray correction coefficients 1 to 5 are 2 for R / G and B / G. Acquired one by one (step S72 to step S80). Then, as shown in the following formulas (5) and (6), the R / G coordinates and the B / G coordinates are multiplied by the gray correction coefficients 1 to 5 to correct the target coordinates (step S82).

(Gray correction value) = (Gray correction coefficient 1) × (Gray correction coefficient 2) × (Gray correction coefficient 3) × (Gray correction coefficient 4) × (Gray correction coefficient 5) (5)
(Corrected R / G coordinate and B / G coordinate) = (R / G coordinate and B / G coordinate) × (gray correction value of R / G coordinate and B / G coordinate) (6)
According to the present embodiment, it is possible to correct a deviation in target coordinates due to pixel mixing caused by a change in transfer efficiency and sensitivity of the CCD 36, a driving frequency, a color temperature of a light source, and a temperature of a housing, and therefore, accurate white balance control. It can be performed.

  In the present embodiment, the gray correction coefficients 1 to 5 corresponding to the R / G coordinate and the B / G coordinate are multiplied. However, the present invention is not limited to this. For example, the following formula ( 7) As shown in FIG. 7, correction values of R / G coordinates and B / G coordinates corresponding to the transfer efficiency and sensitivity of the CCD 36, the driving frequency, the color temperature of the light source, and the temperature of the casing (gray correction values 1 to 5, respectively) May be added to the R / G coordinate and the B / G coordinate. As a method for correcting the R / G coordinate and the B / G coordinate, either addition / subtraction / multiplication / division may be used.

  (Corrected R / G coordinates and B / G coordinates) = (R / G coordinates and B / G coordinates) + (Gray correction value 1) + (Gray correction value 2) + (Gray correction value 3) + (Gray Correction value 4) + (Gray correction value 5) (7)

1 is a block diagram illustrating a main configuration of an imaging apparatus including a white balance control device according to a first embodiment of the present invention. The figure which shows typically the transfer route of the electric charge in CCD36 8 is a flowchart showing a flow of white balance adjustment processing according to an embodiment of the present invention. The graph which shows typically distribution of the integrated value for WB in R / G and B / G color space Graph showing the locus of black body color change in R / G and B / G color spaces Graph showing how to correct the white balance integrated value A graph illustrating a part of a WB integrated value correction coefficient 1 table showing a relationship between transfer efficiency and WB integrated value correction coefficient 1 Flowchart showing the flow of correction processing for integrated value for WB The block diagram which shows the main structures of an imaging device provided with the white balance control apparatus which concerns on the 2nd Embodiment of this invention. Graph showing correction method of light source evaluation value A graph illustrating a part of a light source evaluation value correction coefficient 1 table showing a relationship between transfer efficiency and light source evaluation value correction coefficient 1 Flow chart showing the flow of light source evaluation value correction processing The block diagram which shows the main structures of an imaging device provided with the white balance control apparatus which concerns on the 3rd Embodiment of this invention. Graph showing target coordinate correction method A graph illustrating a part of a gray correction coefficient 1 table showing a relationship between transfer efficiency and gray correction coefficient 1 Flow chart showing the flow of target coordinate correction processing

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Imaging device (camera), 10 ... Central processing unit (CPU), 12 ... Power supply circuit, 14 ... Bus, 16 ... ROM, 18 ... EEPROM, 20 ... Memory (SDRAM), 22 ... VRAM, 24 ... Operation switch group , 26 ... Image display device (liquid crystal monitor), 28 ... Media socket, 30 ... Recording medium, 32 ... Media controller, 34 ... External connection interface (I / F) section, 36 ... CCD, 38 ... Lens unit, 40 ... Focus Lens: 42 ... Zoom lens, 44 ... Shooting lens, 46 ... Aperture / mechanical shutter, 48 ... Timing generator (TG), 50 ... Analog processing unit (CDS / AMP), 52 ... A / D converter, 54 ... Image input controller 56 ... Image signal processing circuit, 58 ... Video encoder, 60 ... AF detection circuit, 62 ... AE / A B detection circuit, 64 ... compression / decompression circuit, 66 ... video input / output terminal, 68 ... video output circuit, 70 ... transfer efficiency detection unit, 72 ... camera sensitivity detection unit, 74 ... light source color temperature detection unit, 76 ... drive frequency detection , 78 ... Case temperature detection unit, 80 ... WB integrated value correction unit, 82 ... Light source evaluation value correction unit, 84 ... Light source determination unit, 86 ... Coordinate correction unit, 88 ... Target coordinate determination unit, 90 ... Vertical transfer , 92... Horizontal transfer path, 94... Charge-voltage converter, 96 A... One pixel on the effective pixel area side of the boundary changing from the effective pixel area to the OB area, 96 B... OB area changing from the effective pixel area to the OB area 1 pixel on the side

Claims (11)

Integrated value calculating means for calculating an integrated value for white balance adjustment from an image input via the image sensor;
Detecting means for detecting parameters of the image sensor including at least transfer efficiency of the image sensor;
Integrated value correction means for correcting the integrated value based on the detected parameter;
White balance adjustment means for adjusting white balance based on the corrected integrated value;
A white balance control device comprising: The integrated value calculating means calculates a ratio R / G value and B / G value of the integrated value of the G signal to the integrated value of the R and B signals,
2. The integrated value correcting unit corrects the R / G value and the B / G value by performing an operation on at least one of the integrated values of R, B, and G. White balance control device. Further comprising light source information acquisition means for acquiring light source information under shooting conditions based on the calculated integrated value;
The white balance control apparatus according to claim 1, wherein the integrated value correction unit corrects the color information based on the light source information. Integrated value calculating means for calculating an integrated value for white balance adjustment from an image input via the image sensor;
A light source evaluation value calculating means for calculating a light source evaluation value for determining a light source under a photographing condition based on the calculated integrated value;
Detecting means for detecting parameters of the image sensor including at least transfer efficiency of the image sensor;
Light source evaluation value correction means for correcting the light source evaluation value based on the detected parameter;
White balance adjusting means for adjusting white balance based on the corrected light source evaluation value;
A white balance control device comprising:   The white balance control device according to claim 4, wherein the light source evaluation value correction unit calculates a difference between integrated values of the G signal and the R signal. Further comprising light source information acquisition means for acquiring light source information under shooting conditions based on the calculated integrated value;
6. The white balance control device according to claim 4, wherein the light source evaluation value correcting unit corrects the light source evaluation value based on the light source information. Integrated value calculating means for calculating an integrated value for white balance adjustment from an image input via the image sensor;
Gray acquisition means for acquiring gray color information from the calculated integrated value;
Detecting means for detecting parameters of the image sensor including at least transfer efficiency of the image sensor;
Gray correction means for correcting the gray color information based on the detected parameters;
White balance adjustment means for adjusting white balance based on the acquired gray color information;
A white balance control device comprising: The integrated value calculating means calculates a ratio R / G value and B / G value of the integrated value of the G signal to the integrated value of the R and B signals,
8. The gray correction unit corrects the R / G value and the B / G value by performing an operation on at least one of R, B, and G values of the gray color information. The white balance control device described. Further comprising light source information acquisition means for acquiring light source information under shooting conditions based on the calculated integrated value;
9. The white balance control apparatus according to claim 7, wherein the gray correction unit corrects the light source evaluation value based on the light source information.   10. The white balance control device according to claim 1, wherein the parameter of the image sensor includes at least one of sensitivity, drive frequency, and temperature of the image sensor. 11.   An imaging apparatus comprising the white balance control device according to claim 1.

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