JP5123010B2 - Imaging apparatus, imaging method, and program for causing computer included in imaging apparatus to execute imaging method - Google Patents

Description

  The present invention relates to an imaging apparatus, an imaging method, and a program for causing a computer included in the imaging apparatus to execute the imaging method.

Conventionally, in a digital camera or the like, white balance adjustment is performed in order to accurately perform color development under various light sources. As a white balance adjustment method, there is a method in which an image is divided into several blocks and performed based on information (white balance evaluation value) of a plurality of pixels included in each block.
For example, in Patent Document 1, a screen on which a subject is imaged is divided into a plurality of areas, color information of each area is acquired, a light source type is determined from the distribution of color information, and white balance control suitable for the light source type is performed. Is going.
In Patent Document 2, the signal from the image sensor is divided into a plurality of blocks, a color evaluation value group is calculated for each block, and the first color temperature information calculated from a preset white extraction range and the color Based on the second color temperature information and distance information calculated from the evaluation value group and a preset skin detection range, the third color temperature information is calculated to adjust the white balance.
Japanese Patent No. 389834 JP 2004-187147 A

However, as in the inventions described in Patent Documents 1 and 2, when the average value of a plurality of pixels included in each block is used as a reference for white balance adjustment, the average value depends on the state of the pixels included in the block. . Even in an image that captures the same subject, the position and size of the subject change, and the distribution of evaluation values changes as the angle of view changes.
As a result, the evaluation value obtained for each block does not fall within the preset white extraction frame, and the gain is set so that the white extraction block is a light source color and the evaluation value of the white extraction block is white. In the white balance correction processing applied to the light source, there is a problem that the optimum white balance cannot be applied to the actual light source. This problem is caused by a change in the distribution of white balance evaluation values, and is not a problem of the change in the angle of view. Therefore, even if the change in the angle of view is small, white balance adjustment becomes unstable, and accurate color reproduction may not be possible.
The present invention has been made in view of the above circumstances, and stable white even in a scene where white balance is unstable depending on whether or not white can be extracted due to a slight difference in angle of view in still image shooting. An object of the present invention is to provide an imaging apparatus capable of obtaining a balance.

In order to solve the above-described problems, an invention according to claim 1 is directed to an imaging device that converts light incident from an imaging optical system into an electrical signal and outputs the electrical signal, and an imaging signal output from the imaging device. Detection range setting means for setting a detection range for the block, block division means for dividing the detection range set by the detection range setting means into grid blocks, and imaging of each block obtained by the block division means Based on a first white balance evaluation value acquisition means for acquiring an evaluation value for the first white balance from the signal, an evaluation value acquired by the first white balance evaluation value acquisition means, and a preset white extraction range First white extracting means for extracting the white of each block, and a detection range when the number of blocks extracted by the first white extracting means is less than a certain number. And a second white balance evaluation value acquiring means for acquiring an evaluation value for the second white balance from the imaging signal of each change block obtained by changing the detection range by the detection range changing means. An imaging device comprising: a second white extraction unit that performs white extraction of each of the changed blocks based on the evaluation value acquired by the second white balance evaluation value acquisition unit and a preset white extraction range. Features.

According to a second aspect of the present invention, there is provided an imaging step in which the imaging element converts light incident from the imaging optical system into an electrical signal and outputs the electrical signal, and the detection range setting means sets a detection range for the imaging signal. A detection range setting step to set, a block division step in which the block dividing unit divides the detection range into grid-like blocks, and a first white balance evaluation value acquiring unit to evaluate the first white balance from the image pickup signal of each block A first white balance evaluation value acquiring step for extracting a value; and a first white extraction means for extracting white of each block based on a first white balance evaluation value and a preset white extraction range. A white extraction step, a detection range changing step in which the detection range changing means changes the detection range when the number of white extracted blocks is less than a certain number, and each change block in which the detection range has been changed. A second white balance evaluation value acquisition step in which the second white balance evaluation value acquisition means acquires an evaluation value for the second white balance from the image pickup signal of the image, and an evaluation for the second white balance by the second white extraction means. A second white extraction step of performing white extraction of each change block based on a value and a preset white extraction range.

According to a third aspect of the present invention, there is provided a program for causing a computer included in the imaging apparatus to execute the method according to the second aspect.

  According to the present invention, the detection range set for the imaging signal output from the imaging device is divided into grid-like blocks, and the white balance evaluation values of the blocks extracted from the blocks are used. In the image processing apparatus that performs white balance adjustment, if the number of white extracted blocks is less than a certain number, the number of divided blocks is changed, or the white balance is adjusted based on the result of white extraction again after changing the detection range. Since adjustment is performed, white balance adjustment with high accuracy is possible.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 is a diagram illustrating an external configuration of an imaging apparatus (hereinafter referred to as a digital camera) according to the present embodiment.
As shown in FIG. 1, a release button (shutter button) 1, a power button 2, and a shooting / playback switching dial 3 are provided on the upper surface side of the digital camera according to the present embodiment. ) Side, a lens barrel unit 4 having a photographing lens system (imaging optical system), a strobe light emitting unit 5, and an optical viewfinder 6 are provided.
On the back side of the digital camera, there are a liquid crystal monitor (LCD display) 7, an eyepiece 8 of the optical viewfinder 6, a wide-angle zoom (W) switch 9, a telephoto zoom (T) switch 10, and a menu (MENU) button 11. , A confirmation button (OK button) 12 and the like are provided. In addition, a memory card storage unit (not shown) for storing a memory card 13 for storing captured image data is provided inside the side surface of the digital camera.

FIG. 2 is a diagram illustrating a system configuration of the imaging apparatus according to the present embodiment.
As shown in FIG. 2, in this digital camera, a subject image incident through a photographing lens system installed in the lens barrel unit 4 is output from a CCD 21 and a CCD 21 as solid-state imaging elements that form an image on a light receiving surface. An analog front end unit (AFE unit) 22 that processes electrical signals (analog RGB image signals) into digital signals, a signal processing unit 23 that processes digital signals output from the AFE unit 22, an SDRAM 24 that temporarily stores data, A ROM 25, a motor driver 26, and the like in which a control program is stored are provided.
The lens barrel unit 4 includes a photographic lens system having a zoom lens, a focus lens, and the like, an aperture unit, and a mechanical shutter unit. Each drive unit (not shown) of the photographic lens system, the aperture unit, and the mechanical shutter unit includes a motor. It is driven by a driver 26. The motor driver 26 is driven and controlled by a drive signal from a control unit (CPU) 231 of the signal processing unit 23.
In the CCD 21, RGB primary color filters as color separation filters are arranged on a plurality of pixels constituting the CCD 21, and an electrical signal (analog RGB image signal) corresponding to the RGB three primary colors is output.

The AFE unit 22 is sampled by a TG (timing signal generation unit) 221 that drives the CCD 21, a CDS (correlation double sampling unit) 222 that samples an electrical signal (analog RGB image signal) output from the CCD 21, and the CDS 222. An AGC (analog gain control unit) 223 that adjusts the gain of the image signal, and an A / D 224 that converts the image signal gain-adjusted by the AGC 223 into a digital signal (RAW-RGB data).
The signal processing unit 23 outputs a screen horizontal synchronization signal (HD) and a screen vertical synchronization signal (VD) to the TG 221 of the AFE unit 22, and is output from the A / D 224 of the AFE unit 22 in accordance with these synchronization signals. A CCD interface (CCD I / F) 232 for capturing RAW-RGB data, a memory controller 233 for controlling the SDRAM 24, and a YUV conversion unit for converting the captured RAW-RGB data into YUV format image data that can be displayed and recorded 234, a resize processing unit 235 that changes the image size according to the size of the image data to be displayed and recorded, a display output control unit 236 that controls the display output of the image data, and the image data is recorded by JPEG formation or the like. Data compression unit 237 for writing image data to the memory card 13 or Based on a media interface (media I / F) 238 that reads image data written in the card 13 and operation input information from the operation unit, system control of the entire digital camera is performed based on a control program stored in the ROM. A control unit 231 is provided.

The operation unit SW includes a release button 1, a power button 2, a shooting / playback switching dial 3, a wide-angle zoom switch 9, a telephoto zoom switch 10, and a menu button 11 provided on the external surface of the digital camera (see FIG. 1). The confirmation button 12 and the like, and a predetermined operation instruction signal is input to the control unit 231 by the operation of the photographer.
The SDRAM 24 stores RAW-RGB data captured by the CCD I / F 232, and stores YUV data (YUV format image data) converted by the YUV conversion unit 234, and further stores the data in the data compression unit 237. The compressed image data such as JPEG formation is stored.
YUV of the YUV data is information on luminance data (Y), color difference (difference (U) between luminance data and blue (B) component data, and difference (V) between luminance data and red (R) component data). This is a format that expresses colors.

Next, the monitoring operation and still image shooting operation of the digital camera described above will be described. This digital camera performs a still image shooting operation while performing a monitoring operation as described below in the still image shooting mode.
First, when the photographer turns on the power button 2 and sets the photographing / playback switching dial 3 to the photographing mode (still image photographing mode), the digital camera is activated in the recording mode. When the control unit 231 detects that the power button 2 is turned on and the photographing / playback switching dial 3 is set to the photographing mode, the control unit 231 outputs a control signal to the motor driver 26 to switch the lens barrel unit 4. The camera 21 is moved to a photographing position, and the CCD 21, AFE unit 22, signal processing unit 23, SDRAM 24, ROM 25, liquid crystal monitor 7 and the like are activated.
Then, by directing the photographic lens system of the lens barrel unit 4 toward the subject, a subject image incident through the photographic lens system is formed on the light receiving surface of each pixel of the CCD 21. An electrical signal (analog RGB image signal) corresponding to the subject image output from the CCD 21 is input to the A / D 224 via the CDS 222 and the AGC 223, and is converted into 12-bit (RAW) RGB data by the A / D 224. Convert.

This RAW-RGB data is taken into the CCD I / F 232 of the signal processing unit 23 and stored in the SDRAM 24 via the memory controller 233. The RAW-RGB data read from the SDRAM 24 is input to the YUV conversion unit 234 and converted into YUV data (YUV signal) in a displayable format, and then the YUV data is transferred to the SDRAM 24 via the memory controller 233. Is saved.
The YUV data read from the SDRAM 24 via the memory controller 233 is sent to the liquid crystal monitor 7 via the display output control unit 236, and a captured image (or moving image) is displayed. At the time of monitoring in which a photographed image is displayed on the liquid crystal monitor 7, one frame is read out in a time of 1/30 seconds by thinning out the number of pixels by the CCD I / F 232.
In this monitoring operation, the photographed image (or moving image) is only displayed on the liquid crystal monitor 7 functioning as an electronic viewfinder, and the release button 1 is not yet pressed (including half-pressed). .

By displaying the photographed image on the liquid crystal monitor 7, the composition for photographing a still image can be confirmed. In addition, it can output as a TV video signal from the display output control part 236, and a picked-up image (or moving image) can also be displayed on external TV (television) via a video cable.
Then, the CCD I / F 232 of the signal processing unit 23 calculates an AF (automatic focus) evaluation value, an AE (automatic exposure) evaluation value, and an AWB (auto white balance) evaluation value from the captured RAW-RGB data.

The AF evaluation value is calculated by, for example, the output integrated value of the high frequency component extraction filter or the integrated value of the luminance difference between adjacent pixels. When in the in-focus state, the edge portion of the subject is clear, so the high frequency component is the highest. By using this, at the time of AF operation (focus detection operation), AF evaluation values at each focus lens position in the photographing lens system are acquired, and AF operation is performed with the maximum point as the focus detection position. Is executed.
The AE evaluation value and the AWB evaluation value are calculated from the integrated values of the RGB values in the RAW-RGB data. For example, the screen corresponding to the light receiving surfaces of all the pixels of the CCD 21 is equally divided into 256 areas (blocks) (horizontal 16 divisions and vertical 16 divisions), and an RGB integrated value of each area (block) is calculated.
Then, the control unit 231 reads the calculated RGB integrated value, and in the AE process, calculates the luminance of each area (block) on the screen, and determines an appropriate exposure amount from the luminance distribution. Based on the determined exposure amount, exposure conditions (the number of electronic shutters of the CCD, the aperture value of the aperture unit, the insertion and removal of the ND filter, etc.) are set. In the AWB process, an AWB control value that matches the color of the light source of the subject is determined from the RGB distribution. By this AWB process, white balance is adjusted when the YUV conversion unit performs conversion processing to YUV data. Note that the above-described AE process and AWB process are continuously performed during monitoring.

When the still image shooting operation in which the release button 1 is pressed (half-pressed to fully pressed) is started during the monitoring operation described above, the AF operation and the still image recording process that are the focus position detection operations are performed. .
That is, when the release button 1 is pressed (half-pressed to full-pressed), the focus lens of the photographing lens system is moved by a drive command from the control unit 231 to the motor driver 26, for example, so-called hill-climbing AF A contrast evaluation AF operation is performed.
When the AF (focusing) target range is the entire region from infinity to close, the focus lens of the photographing lens system moves to each focus position from close to infinity or from infinity to close to the CCD I / F 232. The control unit 231 reads out the AF evaluation value at each focus position calculated in step. Then, the focus lens is moved to the in-focus position with the point where the AF evaluation value at each focus position is maximized as the in-focus position, and in-focus.

Then, the AE process described above is performed, and when the exposure is completed, the mechanical shutter unit is closed by a drive command from the control unit 231 to the motor driver 26, and an analog RGB image signal for a still image is output from the CCD 21. Then, as in the monitoring, the A / D conversion unit 224 of the AFE unit 22 converts the data into RAW-RGB data.
The RAW-RGB data is taken into the CCD I / F 232 of the signal processing unit 23, converted into YUV data by the YUV conversion unit 234, and stored in the SDRAM 24 via the memory controller 233. The YUV data is read from the SDRAM 24, converted into a size corresponding to the number of recording pixels by the resizing processing unit 235, and compressed to image data such as JPEG format by the data compression unit 237. The compressed image data such as JPEG format is written back to the SDRAM 24, read out from the SDRAM 24 via the memory controller 233, and stored in the memory card 13 via the media I / F 238.

  In the digital camera configured as described above, in the present invention, the control unit 231 controls the imaging signal output from the CCD 21 serving as an imaging device that converts the light incident from the imaging optical system into an electrical signal and outputs the electrical signal. Sets the detection range, divides the detection range set by the CCD I / F 232 into grid-like blocks, and the control unit 231 evaluates the first white balance based on the imaging signal of each block obtained by the CCD I / F 232. The value is extracted, and the first white extraction of each block is performed based on the first white balance evaluation value and the preset white extraction range. If the number of white extracted blocks is less than a certain number, The CCD I / F 232 changes the number of divisions or the detection range of the grid block based on the new detection range set by the control unit 231. The control unit 231 obtains an evaluation value for the second white balance from the image pickup signal of each block obtained by the division and obtained by the CCD I / F 232, and based on the obtained evaluation value and a preset white extraction range. To extract the white of each changed block.

A first embodiment of the present invention implemented using the above-described digital camera will be described with reference to FIG. FIG. 3 is a flowchart showing a series of processes for white balance correction in the present embodiment.
In step S1, detection processing is performed on the captured image. Here, the detection is to calculate an RGB integrated value from the captured image.
As described above, first, the photographed image is RAW-RGB, and the data before signal processing is stored in the SDRAM 24. This data is read from the SDRAM 24 under the control of the control unit 231 and input to the CCD I / F 232. The CCD I / F 232 includes a detection circuit, and divides the entire screen into grid-like blocks based on a predetermined detection frame size and division number set in advance in the ROM 25. For example, the screen corresponding to the light receiving surfaces of all the pixels of the CCD 21 is equally divided into 256 areas (blocks) (horizontal 16 divisions and vertical 16 divisions). And the RGB integrated value of each area (block) is calculated. The RGB integrated values are output to a register readable by the SDRAM 24 or the control unit 231 (step S1).

In step S2, the control unit 231 reads the calculated RGB integrated value, and performs a feature detection process (first white extraction process).
Here, the white extraction process is to extract data at a position considered to be a white pixel (white pixel) from the captured image data, and this process is performed for each of the divided blocks. First, G / R and G / B, which are AWB evaluation values, are calculated for each block from the RGB integrated values acquired in units of blocks. Then, it is determined whether or not the combination of G / R and G / B falls within a preset range. The range in which each block is determined to be a white extraction block is shown in FIG.

FIG. 4 shows two-dimensional color coordinates having G / R as the x-axis and G / B as the y-axis, and the range indicated by the frame 41 is the white extraction range. The frame 41 is set by a plurality of ellipse or circular frames along the black body radiation curve. If G / R and G / B fall within the frame 41, the block is determined as a block in which white pixels exist, that is, a white extraction block, and is stored in the SDRAM 24 (S2).
In the present invention, the number of blocks is counted for the white extraction blocks detected from the detection range in this way, and it is determined whether or not the number of white extraction blocks is equal to or greater than a predetermined reference (step S3). If the number of white extraction blocks is equal to or greater than the predetermined reference (Yes in step S3), the process proceeds to step S4, and the G / R and G / B of each white extraction block is weighted by the corresponding AE evaluation value. G / R and G / B per block are calculated (step S4). The calculation formula is Formula 1.

(Formula 1)

However, WhtAWBR is the AWB evaluation value (G / R) of the white extraction block, WhtAWBB is the AWB evaluation value (G / B) of the white extraction block, WhtAEval is the AE evaluation value of the white extraction block, and WhtCnt Is the number of white extraction blocks, and n is the number of white extraction blocks.
However, when the number of detected white extraction blocks is less than the predetermined number (No in step S3), the process proceeds to step S5, and the detection frame changing process which is a characteristic configuration of the present invention is performed. The detection frame changing process is a process of changing the size and the number of divisions of the detection frame.

5A and 5B are diagrams showing a state before and after the detection frame is changed. FIG. 5A is a diagram showing an example in which the detection frame is shifted in the horizontal direction. FIG. 5B is a diagram in which the detection frame is shifted in the vertical direction. It is a figure which shows an example. In FIG. 5, reference numerals 51a and 52a indicated by thin dotted lines are pre-change detection frames. Reference numerals 51b and 52b indicated by thick solid lines are post-change detection frames.
For example, in step S5, as shown in (a), the post-change detection frame 51b is set to be shifted by a half block in the horizontal direction with respect to the pre-change detection frame 51a. At this time, the left end portion 51L and the right end portion 51R indicated by diagonal lines cannot secure the size of one block by shifting the blocks, so that the detection frame is not included in the post-change detection frame 51b. That is, the detection size after the change is smaller than the detection size before the change.
Alternatively, as shown in (b), the post-change detection frame 52b may be set so as to be shifted by a half block in the vertical direction with respect to the pre-change detection frame 52a. At this time, similarly to the example of (a), the uppermost part 52U and the lowermost part 52B indicated by oblique lines are not included in the post-change detection frame 52b and set the detection frame. Thus, the change form of a divided block is not specifically limited.

After the detection frame changing process, the process proceeds to step S6, and the detection process is performed again.
The control unit 231 reads RAW-RGB from the SDRAM 24 again and inputs it to the CCD-I / F 232. Then, based on the divided blocks of the post-change detection frame, the portion excluding the left and right ends or the upper and lower ends of the entire screen is divided into grid blocks, and the RGB integrated values of the respective areas (blocks) are calculated. The calculated RGB integrated value is output to a register readable by the SDRAM 24 or the control unit 231 (step S6).
In step S7, the RGB integrated value calculated by the control unit 231 is read, and the feature detection process (second white extraction process) is performed again. The specific white extraction processing method is the same as that in step S2, and thus the description thereof is omitted.

In this way, the number of white extraction blocks detected from within the post-change detection frame is counted, and it is determined whether or not the number of white extraction blocks is equal to or greater than a predetermined reference (step S8). If the number of white extraction blocks is equal to or greater than the predetermined standard (Yes in step S8), the process proceeds to step S4, and the G / R and G / B of each white extraction block is weighted by the corresponding AE evaluation value. G / R and G / B per block are calculated according to Equation 1 (step S4).
On the other hand, when the number of white extraction blocks does not satisfy the predetermined standard (No in step S8), the process proceeds to step S9.

  In step S9, G / R and G / B per block are calculated by weighting the AE evaluation values corresponding to G / R and G / B of all blocks (step S9). The calculation formula is Formula 2.

(Formula 2)

However, AllAWBR is the AWB evaluation value (G / R) of all blocks, AllAWBB is the AWB evaluation value of all blocks (G / B), AllAEval is the AE evaluation value of all blocks, AllCnt is the number of blocks of all blocks, and n is all The number of blocks.
As described above, after correction is made for each area on the color coordinates of G / R, G / B to G / R, G / B per block calculated in step S4 and step S9, G / R is set to Rgain, A white balance correction coefficient with G / B as Bgain is set (step S10).

Here, correction for each area means, for example, in a low color temperature side scene where the G / R value is small and the G / B is large, the G / R is increased to reduce the G / B so that the light source color remains. Processing, or if G / R is larger than a certain value in a scene of a high color temperature with a large G / R value and a small G / B, a limit processing is performed that cuts over a predetermined value of G / R. Is. By this processing, it is possible to obtain a white balance gain considering the color temperature.
Thereafter, white balance correction coefficients Rgain and Bgain are applied to the R and B data of the entire screen (step S11), and a series of white balance correction is completed.
In this way, in the present invention, when the white extraction block is not detected by a predetermined amount, the detection frame is changed and the white extraction process is performed again, so even if white extraction cannot be performed in the detection frame before the change, The possibility that white can be extracted in the detection frame after the change increases. Therefore, even if white extraction cannot be performed due to the change in the ratio of achromatic and chromatic colors in the block due to subtle changes in the angle of view, the white extraction accuracy is increased. The white balance adjustment accuracy can be increased.

A second embodiment of the present invention will be described. In the present embodiment, the contents of the detection frame changing process in step S5 of the first embodiment shown in FIG. 3 are different. Below, it demonstrates centering around the process process of step S5 different from 1st embodiment.
First, similarly to the first embodiment, the processes in steps S1 and S2 are performed, and it is determined in step S3 whether or not the number of white extraction blocks is equal to or greater than a predetermined reference. When the number of white extraction blocks detected in the preset detection frame is less than the predetermined amount (No in step S3), the process proceeds to step S5, and detection frame change processing is performed. In the second embodiment, processing for changing the block size of the detection frame is performed.

FIG. 6 is one example showing the changed detection frame block, and FIG. 7 is another example showing the changed detection frame block. For example, when the number of blocks before the change is horizontal 16 × vertical 16 divisions, the horizontal 2 blocks and the vertical 2 blocks are integrated and changed to horizontal 8 × vertical 8 divisions as shown in FIG. Also, as shown in FIG. 7A, two horizontal blocks are integrated into horizontal 8 × vertical 16 divisions, or as shown in FIG. 7B, two vertical blocks are integrated into horizontal 16 × vertical eight divisions. Also good. Thus, the change form of a divided block is not specifically limited.
Then, detection is performed again based on the changed divided block of the detection frame (step S6). Since the subsequent processing is the same as that of the first embodiment, description thereof is omitted.

  In this way, when white cannot be extracted with the distribution of G / R and G / B diffused on the two-dimensional color coordinates, the block size used for screen division is increased to increase the average for many pixels. Since the diffusion of the distributed G / R and G / B distribution can be suppressed, the possibility that G / R and G / B fall into the white extraction frame shown in FIG. 4 increases. Accordingly, it is possible to perform white balance adjustment with higher accuracy than calculating the white balance gain from the integrated values of all blocks. Also, usually, by increasing the number of block divisions, the number of pixels to be averaged decreases and the white extraction accuracy can be increased. Therefore, according to the present invention, high-accuracy white balance adjustment is performed regardless of the number of white extraction blocks. It can be performed.

It is a figure which shows the external appearance structure of an imaging device. It is a figure which shows the system configuration | structure of an imaging device. It is a flowchart showing a series of processes of white balance correction. It is a figure explaining a white extraction range. It is a figure which shows the mode before and after the change of a detection frame, (a) is a figure which shows the example which shifts a detection frame to a horizontal direction, (b) is a figure which shows the example which shifts a detection frame to a vertical direction, and changes it It is. It is a figure which shows the block of the detection frame changed. (A), (b) is a figure which shows the block of the changed detection frame.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Release button, 2 ... Power button, 3 ... Shooting / playback switching dial, 4 ... Lens barrel unit, 5 ... Strobe light emitting unit, 6 ... Optical viewfinder, 7 ... LCD monitor, 8 ... Eyepiece lens unit, 9 ... Wide angle side Zoom switch, 10 ... Telephoto zoom switch, 11 ... Menu button, 12 ... Confirm button, 13 ... Memory card, 21 ... CCD, 22 ... AFE section, 221 ... TG, 222 ... CDS, 223 ... AGC, 224 ... A / D conversion unit, 23 ... signal processing unit, 231 ... control unit, 232 ... CCD I / F, 233 ... memory controller, 234 ... YUV conversion unit, 235 ... resize processing unit, 236 ... display output control unit, 237 ... data compression unit 238 ... Media I / F, 24 ... SDRAM, 25 ... ROM, 26 ... Motor driver, SW ... Operation unit, 41 ... Frame, 51a ... Detection frame before change 51b ... after change detection frame, 51L ... left end, 51R ... right end, 52a ... pre-change detection frame, 52 b ... post-change detection frame, 52U ... upper portion, 52B ... lower end

Claims (3)

  An imaging device that converts light incident from the imaging optical system into an electrical signal and outputs the signal as an imaging signal, a detection range setting unit that sets a detection range for the imaging signal output from the imaging device, and the detection range setting Block dividing means for dividing the detection range set by the means into grid blocks, and a first white balance for obtaining an evaluation value for the first white balance from the image pickup signal of each block obtained by the block dividing means Evaluation value acquisition means; first white extraction means for extracting white of each block based on the evaluation value acquired by the first white balance evaluation value acquisition means and a preset white extraction range; and A detection range changing means for changing a detection range when the number of blocks extracted by one white extraction means is less than a certain number; and the detection range changing means. Obtained by second white balance evaluation value acquisition means for acquiring an evaluation value for the second white balance from the imaging signal of each change block obtained by changing the detection range, and the second white balance evaluation value acquisition means An imaging apparatus comprising: a second white extraction unit configured to perform white extraction of each change block based on an evaluation value and a preset white extraction range.   An imaging step in which the image sensor converts light incident from the imaging optical system into an electrical signal and outputs the signal as an imaging signal, a detection range setting step in which the detection range setting unit sets a detection range for the imaging signal, and a block division unit Divides the detection range into grid-like blocks, and first white balance evaluation value acquisition means for extracting the first white balance evaluation value from the imaging signal of each block by the first white balance evaluation value acquisition means And a first white extraction step in which the first white extraction means performs white extraction of each of the blocks based on a first white balance evaluation value and a preset white extraction range, and a white extracted block Detection range changing step in which the detection range changing means changes the detection range when the detection range is less than a certain number, and the second white from the imaging signal of each change block in which the detection range is changed A second white balance evaluation value acquisition step in which the lance evaluation value acquisition unit acquires an evaluation value for the second white balance, and a second white extraction unit acquires a second white balance evaluation value and a preset white extraction And a second white extraction step of performing white extraction of each of the changed blocks based on a range. The program for making the computer with which an imaging device is provided perform the method of Claim 2 .

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