JP2008067298A - Photography apparatus and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve manipulability and processing precision at the time of preset white balance adjustment. <P>SOLUTION: In a digital camera 10, a manipulation of a cursor key moves a cursor into an achromatic color area on a finder image of a display device 15. Then, when a manipulation of a determination key designates one point on the achromatic color area, color information of a pixel of the designated point is analyzed to extract an area (achromatic color area) with the same color as that of the designated area to obtain the color information of R/G/B color components on the extracted achromatic color area. Each of gain adjustment values of R/G/B is calculated based on the obtained color information. For all pixels constituting image data of the finder image, each gain is adjusted based on each of the calculated gain adjustment values of R/G/B for white balance adjustment. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a photographing apparatus and a program for performing white balance adjustment on image data captured by an image sensor.

  Conventionally, in a photographing apparatus such as a digital camera or a video camera, white balance adjustment is performed on an image captured by an image sensor. White balance adjustment is a process for reproducing an achromatic object as an achromatic color even when shooting under a light source having a different color temperature. The gain of an image signal output from the image sensor is R, Adjustment is made for each of the G and B color components. As white balance adjustment methods, auto white balance, fixed white balance, preset white balance, and the like have been proposed.

  In auto white balance, the color component of an image is determined, the light source is automatically determined, and the color component is adjusted. In the fixed white balance, a light source mode (sunlight, fluorescent light, incandescent light) prepared in advance is set by the user, and color components are adjusted according to the set light source mode. In the preset white balance, a blank sheet or the like is photographed before photographing, the light source state is stored in the camera, and the color components are adjusted based on the stored light source state.

However, auto white balance is sufficiently practical for shooting under a general light source (under a flat light source such as sunlight or fluorescent light), but the situation where the light source changes frequently and the color of the object Appropriate white balance may not be achieved depending on the condition.
In the case of fixed white balance, there is a problem that it cannot be applied to a light source in an intermediate range (for example, a light source intermediate between a fluorescent lamp and a light bulb).
In the case of preset white balance, white paper or the like must be prepared before photographing to perform preset photographing, and the operation is complicated. Further, when the photographer cannot keep close to the place where the light source is shining, for example, it cannot be used for stage photography.

Thus, for example, Patent Document 1 discloses that an achromatic range is specified by capturing a subject assumed to be achromatic in advance in a circular area provided in the center of the finder, and is obtained by shooting. In addition, a technique for performing gain adjustment of color data based on pixel data in a designated achromatic color range is described.
JP 2002-281522 A

  However, in the above-described Patent Document 1, it is necessary to perform preset shooting with a composition different from the actual shooting, that is, with an achromatic color subject placed in the center of the viewfinder before the actual shooting, and the operation is complicated. . In addition, when the achromatic object is smaller than the circular area, there is a problem that the white balance cannot be adjusted with high accuracy because the other color is included although it should have been designated as the achromatic color range. Furthermore, it is necessary to perform preset photography every time the light source changes.

  An object of the present invention is to improve operability and processing accuracy during preset white balance adjustment.

In order to solve the above-mentioned problem, the invention described in claim 1
In an imaging device including an image acquisition unit that converts an optical image of a subject into an electrical signal to acquire image data,
Display means for displaying an image based on the image data acquired by the image acquisition means;
Designation means for arbitrarily designating an achromatic region of the image displayed on the display means;
Extraction means for extracting an achromatic region from the acquired image data based on the designation by the designation means;
An adjustment value calculating means for calculating a gain adjustment value for each color component based on the extracted image data of the achromatic region;
White balance adjustment means for performing white balance adjustment on the acquired image data based on the calculated gain adjustment value;
It is characterized by having.

The invention described in claim 3
A computer used in a photographing apparatus including an image acquisition unit that converts an optical image of a subject into an electrical signal to acquire image data.
Display means for displaying an image based on the image data acquired by the image acquisition means;
Designation means for arbitrarily designating an achromatic region of the image displayed on the display means;
Extraction means for extracting an achromatic region from the acquired image data based on the designation by the designation means;
Adjustment value calculation means for calculating a gain adjustment value for each color component based on the extracted image data of the achromatic region;
White balance adjustment means for performing white balance adjustment on the acquired image data based on the calculated gain adjustment value;
It is a program for making it function as.

  According to the first and third aspects of the present invention, an image based on the image data acquired by the image acquisition unit is displayed by the display unit, and the achromatic region of the image displayed on the display unit by the specifying unit is arbitrarily specified. Then, based on the designation by the designation means, the achromatic region is extracted from the acquired image data, and the gain adjustment value for each color component is calculated based on the extracted achromatic color region image data. Based on the gain adjustment value, white balance adjustment is performed on the acquired image data.

  Accordingly, when an achromatic color area is arbitrarily designated from an image obtained by the image obtaining means displayed on the display means, that is, an image for finder display, a gain adjustment value used for white balance adjustment is calculated from the designated achromatic color area. Therefore, there is no need to perform an operation such as performing preset shooting with a composition different from the actual composition and moving the image capturing apparatus body again at the time of shooting. In addition, since the achromatic region is extracted from the acquired image based on the designation by the designation means, and the extracted achromatic region is used for calculating the gain adjustment value, the achromatic region is set in a predetermined region in the finder. As in the case of preset shooting, the size of the predetermined area of the finder and the size of the achromatic area are different, so that other non-achromatic colors are not included in the pixels for gain calculation. A good white balance can be adjusted.

  According to the second aspect of the present invention, the extracted image data of the achromatic region is stored, and when image data is newly acquired from the image acquisition means, the stored image data of the achromatic region is stored. Based on this, the position of the achromatic region in the acquired image data is specified, a gain adjustment value is calculated based on the image data of the specified achromatic region, and white balance adjustment is performed. Therefore, even if the light source changes during photographing, the white balance can be adjusted in real time and the white balance can be adjusted in real time.

(Embodiment 1)
Hereinafter, the digital camera 10 according to Embodiment 1 of the present invention will be described in detail.
First, the configuration will be described.
FIG. 1 is a block diagram showing a functional configuration of the digital camera 10. As shown in FIG. 1, a digital camera 10 includes a CPU (Central Processing Unit) 11, an input device 12, a RAM (Random Access Memory) 13, a transmission control unit 14, a display device 15, an imaging device 16, a recording device 17, and the like. Each part and each device are connected by a bus 18.

  The CPU 11 reads out a system program stored in the recording device 17, develops it in a work area formed in the RAM 13, and controls each unit according to the system program. Further, the CPU 11 reads out various processing programs such as a main processing program and a white balance processing program stored in the recording device 17 and expands them in a work area, and software processing by cooperation with the expanded programs. Thus, various processes including a main process (see FIG. 4) and a white balance process (see FIG. 5) described later are executed.

Further, the CPU 11 realizes an extraction unit, an adjustment value calculation unit, and a white balance adjustment unit by software processing in cooperation with the extraction program, the adjustment value calculation program, and the white balance adjustment program stored in the recording device 17. .
That is, when the CPU 11 extracts an achromatic region (hereinafter referred to as an achromatic area) from the finder image in the white balance process, the CPU 11 reads the extraction program and points specified in the finder image captured by the imaging device 16. Are extracted as achromatic areas.
Further, when calculating the gain adjustment value in the white balance process, the CPU 11 reads the adjustment value calculation program, and obtains the gain adjustment value for each of the R, G, and B color components based on the image data of the achromatic color area. calculate.
Further, the CPU 11 reads out a white balance adjustment program and obtains it based on the calculated gain adjustment value when performing white balance adjustment on the image data acquired by the imaging device 16 in the main processing and white balance processing. White balance adjustment is applied to the recorded image data.

  The input device 12 includes a power key (not shown), a shutter key K1, and cross keys K2 to indicate the up, down, left, and right directions on the display screen for moving the cursor position on the display screen of the display device 15. K5, and a determination key K6, which is arranged at the center of the cross keys K2 to K5 and designates and sets the content selected by the cursor at that time. The input device 12 also includes a mode switch (not shown) for switching the operation mode of the digital camera 10 such as a shooting mode, an end mode, and a playback mode, and an operation signal corresponding to each key operation or switch operation by the photographer. Is output to the CPU 11. Furthermore, the input device 12 includes a setting key K7 for instructing an achromatic color area setting operation for white balance adjustment, and outputs an operation signal to the CPU 11 in accordance with the operation of the setting key K7 by the photographer.

  For example, the cross keys K2 to K5, the enter key K6, and the setting key K7 are provided together with the display screen of the display device 15 on the back of the digital camera 10, as shown in FIG. The keys can be operated.

  In a state where the finder image and the cursor are displayed on the display screen in the display device 15, the cross keys K2 to K5 and the enter key K6 function as designation means. That is, when the cursor is moved by operating the cross keys K2 to K5 and the determination key K6 is pressed, an achromatic region on the finder image can be designated.

  The RAM 13 forms a work area for temporarily storing various programs executed by the CPU 11 and data related to these programs. The RAM 13 forms an area setting memory 131 and a gain adjustment value memory 132.

  The transmission control unit 14 is connected to an external electronic device such as a personal computer via a communication cable or the like, and controls transmission / reception of image data and the like. The connection with the external device may be a wireless connection such as infrared or wireless.

  The display device 15 is configured by a monitor such as an LCD (Liquid Crystal Display), and displays an image to be photographed, a photographed image, and the like on a display screen in accordance with an instruction of a display signal input from the CPU 11.

  FIG. 3 is a diagram illustrating a detailed configuration of the imaging device 16. The imaging device 16 has a function as an image acquisition unit that acquires an image data by converting an optical image of a subject into an electrical signal. Here, the imaging device 16 will be described with reference to FIG.

  The subject image that has passed through the imaging lens 21 is imaged on a CCD (Charge Coupled Device) 23 as an imaging device via a diaphragm mechanism 22. The imaging lens 21 and the diaphragm mechanism 22 are moved by the optical system driving unit 24 for focus adjustment (focus adjustment), and the diaphragm amount is controlled so as to achieve appropriate exposure. For the movement of the imaging lens 21 and the diaphragm mechanism 22, the detection value detected by the sensor unit 25 including a distance measuring sensor and a light quantity sensor is output to the CPU 11 via the bus 18, and the CPU 11 calculates based on the detection value. Driving is performed by outputting a signal indicating the amount of movement of the image pickup lens 21 and the amount of aperture of the aperture mechanism 22 to the optical system drive unit 24.

  When the subject is imaged on the CCD 23, charges corresponding to the amount of incident light are accumulated in the CCD 23. This electric charge is sequentially read out as a voltage signal by a drive pulse signal supplied from the drive circuit 26 and output to the A / D conversion circuit 27. In the A / D conversion circuit 27, the input voltage signal is converted into digital image data (hereinafter referred to as image data), and the converted image data is stored in the buffer register 28.

  The image data stored in the buffer register 28 is subjected to white balance adjustment by software processing in cooperation with the CPU 11 and the program stored in the recording device 17. The image data subjected to the white balance adjustment is converted into a luminance signal and a color difference signal by the signal processing circuit 29 based on a control signal from the CPU 11 and displayed on the display device 15. Further, the image data processed in the signal processing circuit 29 is compressed in the compression / decompression circuit 30 based on a control signal from the CPU 11 and is stored in the photographed image recording area 171 of the recording device 17 shown in FIG. To be recorded.

  Returning to FIG. 1, the recording device 17 includes a non-volatile memory such as a flash memory, and includes a system program corresponding to the digital camera 10, a main processing program that can be executed on the system program, and a white balance processing program. Various processing programs, application programs, and data processed by these programs are recorded. The recording device 17 has a captured image recording area 171 for recording captured image data.

Next, the operation will be described.
FIG. 4 is a flowchart showing main processing executed by the CPU 11 of the digital camera 10. This process is a process realized by software processing in cooperation with the CPU 11 and the main processing program stored in the recording device 17 when the power is turned on by operating the power key of the input device 12.

  First, a mode selection screen for selecting an operation mode is displayed on the display device 15. When the operation mode is selected by operating the cursor keys K2 to K5 and the enter key K6 on the mode selection screen (step S1), setting is performed. The performed operation mode is analyzed (step S2). When the set operation mode is the shooting mode (step S3; YES), the imaging device 16 is controlled and image data for finder display is captured (acquired) (step S4). Like the image data captured in step S4, the image data captured from the imaging device 16 for display on the display device 15 for shooting reference in the shooting standby state is referred to as a viewfinder image.

  When the finder image is captured, the white balance process shown in FIG. 5 is executed based on the captured finder image (step S5).

  FIG. 5 is a flowchart showing white balance processing executed by the CPU 11 of the digital camera 10. This processing is realized by software processing in cooperation with the CPU 11 and the white balance processing program stored in the recording device 17.

  When the image data of the finder image is captured by the imaging device 16, the finder image is displayed on the display device 15 based on the captured image data (step S101). Next, it is determined whether or not there is data in the area setting memory 131, that is, whether or not data is stored, and if it is determined that no data is stored in the area setting memory 131 (step S102; NO). The process proceeds to step S104. If it is determined that the data is stored in the area setting memory 131 (step S102; YES), it is determined whether or not the setting key K7 for instructing the setting of the achromatic area is pressed, and it is determined that the data is pressed. If so (step S103; YES), the process proceeds to step S104.

  In step S104, the cursor A is displayed on the screen (finder screen) on which the finder image of the display device 15 is displayed. FIG. 2 shows an example of a viewfinder screen displayed in step S104. The cursor A is moved into the achromatic area of the image displayed by at least one operation of the cursor keys K2 to K5 of the input device 12, and a point on the achromatic area is designated by the operation of the decision key K6. Then (step S105), the color information of the pixel at the designated point is analyzed, and an area (achromatic area) having the same color as the designated point is extracted (step S106). Then, the position information of the extracted achromatic color area is stored in the area setting memory 131 (step S107), and overlay processing for performing blinking and contour enhancement is performed on the extracted achromatic color area (step S108). On the finder screen of the display device 15, the extracted achromatic area is displayed in an overlay so as to be distinguishable by blinking or contour enhancement (step S109). FIG. 6 shows an example of the overlay display displayed in step S109 when the achromatic area is designated at the cursor position shown in FIG.

  Next, color information of each of the R, G, and B color components of the extracted achromatic color area image data is acquired, and based on the acquired color information, an adjustment value of each gain of R, G, and B is obtained. The calculated gain adjustment value of each color is written (overwritten) in the gain adjustment value memory 132 (step S111). Then, with respect to all the pixels constituting the image data of the finder image, the white balance adjustment is performed by adjusting the respective gains based on the calculated adjustment values of the respective R, G, and B gains (step S112). ) The adjusted viewfinder image is displayed on the display device 15 (step S113), and the process proceeds to step S6 in FIG.

  The gain adjustment values of the R, G, and B color components calculated in step S110 suppress the gain of the color component protruding from the gray component based on the acquired balance of the respective color components (or increase the gain of the complementary color). ) Is an adjustment value for adjustment. For example, when the color components of the achromatic area are (R: G: B) = (150: 100: 120), respectively, with any color as a reference (here, G is the reference), (R = G = The gain adjustment value of each color is calculated so that B), and the gain adjustment value Δ (R: G: B) = (− 50: 0: −20) is acquired.

  On the other hand, if it is determined in step S103 that the setting key K7 for instructing the setting of the achromatic color area has not been pressed (step S103; NO), the gain adjustment value of each color is read from the gain adjustment value memory 132. Then, with respect to all the pixels constituting the image data of the finder image, white balance adjustment is performed by adjusting the R, G, and B gains based on the read gain adjustment values (step S112). The adjusted viewfinder image is displayed on the display device 15 (step S113), and the process proceeds to step S6 in FIG.

  In step S6 of FIG. 4, it is determined whether or not the shutter key K1 has been pressed. If it is determined that the shutter key K1 has been pressed (step S6; YES), the imaging device 16 is controlled to perform shooting. The captured image data is captured (step S7), the gain adjustment value stored in the gain adjustment value memory 132 is read, and white balance adjustment is performed on the captured image data based on the read gain adjustment value. Then, it is displayed on the display device 15 (step S8), and the image data of the captured image whose white balance has been adjusted is recorded in the captured image recording area 171 of the recording device 17 (step S9). Next, it is determined whether or not mode switching has been instructed by operating a mode switching switch of the input device 12 or the like. If it is determined that mode switching has not been instructed (step S10; NO), the process returns to step S4. . If it is determined that mode switching has been instructed (step S10; YES), it is determined whether or not the mode has been switched to the end mode. If it is determined that the mode has been switched to a mode other than the end mode (step S11; NO), processing is performed. Returns to step S2. If it is determined that the mode has been switched to the end mode (step S11; YES), this process ends.

  On the other hand, if it is determined in step S3 that the set operation mode is not the shooting mode (step S3; NO), processing according to the operation mode is executed (step S12). For example, when the current operation mode is the playback mode, a list of images recorded in the captured image recording area 171 of the recording device 17 is displayed on the display screen, and a captured image selected from the image list is reproduced and displayed. . Processing according to the operation mode is executed until mode switching is instructed by operating the mode selector switch of the input device 12, and when mode switching is instructed by operating the mode selector switch of the input device 12 (step S13; YES), it is determined whether or not the mode has been switched to the end mode. If it is determined that the mode has been switched to a mode other than the end mode (step S14; NO), the process returns to step S2. If it is determined that the mode has been switched to the end mode (step S14; YES), this process ends.

  As described above, in the digital camera 10 according to the first embodiment, the position of the achromatic color area of the finder image displayed on the display device 15 can be arbitrarily specified, and the color information of the specified achromatic color area is included. A gain adjustment value is calculated based on the white balance adjustment. Therefore, there is no need to perform preset shooting with a composition different from the actual one and move the camera body at the time of shooting as before, and it is possible to easily specify points in the achromatic area from the finder image. The operability at the time is improved. In addition, an area of the same color as the point specified on the finder image is extracted as an achromatic color area, and a gain adjustment value is calculated based on the color information of the extracted achromatic color area. It becomes possible.

(Embodiment 2)
Next, Embodiment 2 of the present invention will be described.
In the second embodiment, the white balance process executed in step S5 of the main process described in FIG. 4 and the white balance adjustment process of the captured image executed in step S8 are different from those described in the first embodiment. The configuration of the digital camera 10 according to the second embodiment is substantially the same as that described with reference to FIGS. 1 and 2, but the white balance process (hereinafter referred to as white balance process B) according to the second embodiment is executed on the recording apparatus 17. And a white balance adjustment process B program for the photographed image for executing the white balance adjustment process for the photographed image in the second embodiment (hereinafter referred to as the white balance adjustment process B for the photographed image). Has been. The CPU 11 reads out various processing programs such as the main processing program, the white balance processing B program, and the white balance adjustment processing B program for the captured image stored in the recording device 17 and develops them in the work area. Various processes including a main process (see FIG. 4), a white balance process B (see FIG. 7), and a white balance adjustment process B (see FIG. 8) of a captured image, which will be described later, by software processing in cooperation with the program. Execute.

Further, the CPU 11 performs extraction processing, achromatic color area specifying means by software processing in cooperation with an extraction program, an achromatic color area position specifying program, an adjustment value calculation program, and a white balance adjustment program stored in the recording device 17. An adjustment value calculation unit and a white balance adjustment unit are realized.
That is, when the CPU 11 extracts an achromatic region (hereinafter referred to as an achromatic area) from the finder image in the white balance process B, the CPU 11 reads the extraction program and is specified in the finder image captured by the imaging device 16. An area having the same color as the point is extracted as an achromatic area.
Further, the CPU 11 reads an achromatic color region position specifying program when specifying the achromatic color region position of the image data acquired by the imaging device 16 in the white balance processing B and the white balance adjustment processing B of the captured image, and will be described later. Based on the image data stored in the area image memory 133, the achromatic color region position of the acquired image data is specified.
In addition, when calculating the gain adjustment value in the white balance process B and the white balance adjustment process B of the captured image, the CPU 11 reads the adjustment value calculation program, and based on the image data of the achromatic area, R, G, A gain adjustment value for each color component of B is calculated.
Further, the CPU 11 reads the white balance adjustment program and performs the calculated gain adjustment when performing the white balance adjustment on the image data acquired by the imaging device 16 in the white balance process B and the white balance adjustment process B of the captured image. Based on the value, white balance adjustment is performed on the acquired image data.

  In addition to the area setting memory 131 and the gain adjustment value memory 132, the RAM 13 forms an area image memory 133 as an achromatic color area image storage unit (not shown). Other configurations are the same as those described in the first embodiment, and thus description thereof is omitted. The main process executed when the power is turned on in the digital camera 10 is the same as that described with reference to FIG. Hereinafter, the white balance processing B and the captured image white balance adjustment processing B according to the second embodiment will be described with reference to the drawings.

  First, the white balance process B will be described. FIG. 7 is a flowchart illustrating white balance processing B executed by the CPU 11 of the digital camera 10 according to the second embodiment. This process is a process realized by a software process in cooperation with the CPU 11 and the white balance process B program stored in the recording device 17 in step S5 of FIG.

  When the image data of the finder image is captured by the imaging device 16, the captured image data is displayed on the display device 15 (step S201). Next, it is determined whether or not there is data in the area setting memory 131, that is, whether or not data is stored. If it is determined that no data is stored in the area setting memory 131 (step S202; NO). The process proceeds to step S204. If it is determined that data is stored in the area setting memory 131 (step S202; YES), it is determined whether or not the setting key K7 for instructing the setting of the achromatic color area is pressed, and it is determined that the data is pressed. If so (step S203; YES), the process proceeds to step S204.

  In step S204, the cursor A is displayed on the screen (finder screen) on which the finder image of the display device 15 is displayed. When the cursor A is moved into the achromatic area by operating at least one of the cursor keys K2 to K5 of the input device 12, and a point on the achromatic area is designated by operating the decision key K6 (step S205). Then, the color information of the pixel at the designated point is analyzed, and an area (achromatic area) having the same color as the designated point is extracted (step S206). Then, the position information (coordinate information in the finder image) of the extracted achromatic area is stored in the area setting memory 131 (step S207), and the extracted achromatic area image data (achromatic area image) is the area. It is stored in the image memory 133 (step S208).

  Next, overlay processing is performed on the extracted achromatic area to perform blinking and contour enhancement (step S209), and the extracted achromatic color area can be identified by blinking and contour enhancement on the finder screen of the display device 15. Is displayed in an overlay (step S210).

  Next, the respective color information of the R, G, and B color components of the achromatic area in which the position information is stored in the area setting memory 131 is acquired, and based on the acquired color information, the R, G, and B color components are acquired. An adjustment value of each gain is calculated (step S211), and each gain is adjusted based on the calculated R, G, and B gain adjustment values for all the pixels constituting the image data of the finder image. Thus, white balance adjustment is performed (step S212), the adjusted viewfinder image is displayed on the display device 15 (step S213), and the process proceeds to step S6 in FIG.

  The gain adjustment values for the R, G, and B color components calculated in step S211 suppress the gain of the color component protruding from the gray component (or increase the gain of the complementary color) based on the acquired balance of the respective color components. ) Is an adjustment value for adjustment. For example, when the color components of the achromatic area are (R: G: B) = (150: 100: 120), respectively, with any color as a reference (here, G is the reference), (R = G = The gain adjustment value of each color is calculated so that B), and the gain adjustment value Δ (R: G: B) = (− 50: 0: −20) is acquired.

  On the other hand, if it is determined in step S203 that the setting key K7 for instructing the setting of the achromatic color area has not been pressed (step S203; NO), the achromatic color area image stored in the area image memory 133 is displayed. Based on the image data of the finder image captured by the imaging device 16, the position of the achromatic area is specified (step S214). For example, the position of the achromatic color area is specified by performing pattern matching on the image data captured from the imaging device 16 using the achromatic color area image read from the area image memory 133 as a reference pattern.

  Next, the position of the specified achromatic area and the position information in the area setting memory 131 are compared to determine whether or not they match, and if they match (step S215; YES), The process proceeds to step S209, the processes from step S209 to step S213 are executed, and the process proceeds to step S6 in FIG. If it is determined that the position of the specified achromatic area does not match the position information in the area setting memory 131 (step S215; NO), the position information in the area setting memory 131 is the information on the position specified in step S214. (Step S216), the process proceeds to step S209, the processes from step S209 to step S213 are executed, and the process proceeds to step S6 in FIG.

  Next, the white balance adjustment process B of the captured image will be described. FIG. 8 is a flowchart showing white balance adjustment processing B of a captured image executed by the CPU 11 of the digital camera 10 according to the second embodiment. This process is a process realized by software processing in cooperation with the CPU 11 and the white balance adjustment processing B program for the captured image stored in the recording device 17 in step S8 of FIG.

  When the image data of the photographed image is captured by the imaging device 16, the position of the achromatic area is specified from the image data of the photographed image based on the achromatic area image stored in the area image memory 133 (step S301). . For example, the position of the achromatic color area is specified by performing pattern matching on the image data captured from the imaging device 16 using the achromatic color area image read from the area image memory 133 as a reference pattern.

  Next, the position of the specified achromatic area and the position information in the area setting memory 131 are compared to determine whether or not they match, and if they match (step S302; YES), The process proceeds to step S304. If it is determined that the position of the specified achromatic area does not match the position information in the area setting memory 131 (step S302; NO), the position information in the area setting memory 131 is the information on the position specified in step S301. (Step S303), and the process proceeds to step S304.

  In step S304, the respective color information of the R, G, B color components of the achromatic color area whose position information is stored in the area setting memory 131 is acquired, and based on the acquired color information, R, G , B gain adjustment values are calculated (step S304), and for all the pixels constituting the image data of the finder image, the gains are adjusted based on the calculated R, G, B gain adjustment values. As a result, white balance adjustment is performed (step S305), the captured image with the white balance adjusted is displayed on the display device 15 (step S306), and the process proceeds to step S9 in FIG.

  As described above, in the digital camera 10 according to the second embodiment, the image of the achromatic area designated on the finder screen is stored in the area image memory 133, and a new finder image or captured image is acquired from the imaging device 16. Is acquired, the position of the achromatic area is specified from the newly acquired image data based on the achromatic area image stored in the area image memory 133, and the color of the specified achromatic area is determined. Based on the information, a gain adjustment value is calculated and white balance adjustment is performed. Therefore, even if the light source changes during photographing, the white balance can be adjusted in real time and the white balance can be adjusted in real time.

  Note that the description in the first and second embodiments is a preferred example of the digital camera 10 according to the present invention, and the present invention is not limited to this.

  For example, in the first embodiment, the position information of the achromatic color area is stored in the area setting memory 131. However, an image from which the achromatic color area is extracted may be cut out and stored in the area setting memory 131.

  In the second embodiment, the position of the achromatic color area is specified every time a finder image is captured from the imaging device 16, but the achromatic color area may be specified every predetermined frame.

  In addition, the detailed configuration and detailed operation of the digital camera 10 can be changed as appropriate without departing from the spirit of the present invention.

It is a block diagram which shows the functional structure of the digital camera 10 which concerns on Embodiment 1 of this invention. 1 is a diagram showing a back surface of a digital camera 10. It is a figure which shows the detailed structure of the imaging device 16 of FIG. It is a flowchart which shows the main process performed by CPU11 of FIG. It is a flowchart which shows the white balance process performed by CPU11 of FIG. It is a figure which shows an example of the overlay display displayed when the achromatic area is designated at the cursor position shown in FIG. It is a flowchart which shows the white balance process B performed by CPU11 of FIG. It is a flowchart which shows the picked-up image white balance adjustment process B performed by CPU11 of FIG.

Explanation of symbols

10 Digital camera 11 CPU
12 Input device 13 RAM
131 Area setting memory 132 Gain adjustment value memory 133 Area image memory 14 Transmission control unit 15 Display device 16 Imaging device 17 Recording device 171 Captured image recording area 18 Bus 21 Imaging lens 22 Aperture mechanism 23 CCD
24 Optical system drive unit 25 Sensor unit 26 Drive circuit 27 A / D conversion circuit 28 Buffer register 29 Signal processing circuit 30 Compression / decompression circuit

Claims (3)

In an imaging device including an image acquisition unit that converts an optical image of a subject into an electrical signal to acquire image data,
Display means for displaying an image based on the image data acquired by the image acquisition means;
Designation means for arbitrarily designating an achromatic region of the image displayed on the display means;
Extraction means for extracting an achromatic region from the acquired image data based on the designation by the designation means;
An adjustment value calculating means for calculating a gain adjustment value for each color component based on the extracted image data of the achromatic region;
White balance adjustment means for performing white balance adjustment on the acquired image data based on the calculated gain adjustment value;
An imaging apparatus comprising: Achromatic area image storage means for storing image data of the achromatic area extracted by the extraction means;
Achromatic area position specifying means for specifying the position of the achromatic color area in the image data newly acquired from the image acquisition means based on the image data of the achromatic color area stored in the storage means,
The adjustment value calculation unit calculates a gain adjustment value for each color component based on image data of an achromatic color region whose position is specified by the achromatic color region position specifying unit. Shooting device. A computer used in a photographing apparatus including an image acquisition unit that converts an optical image of a subject into an electrical signal to acquire image data.
Display means for displaying an image based on the image data acquired by the image acquisition means;
Designation means for arbitrarily designating an achromatic region of the image displayed on the display means;
Extraction means for extracting an achromatic region from the acquired image data based on the designation by the designation means;
Adjustment value calculation means for calculating a gain adjustment value for each color component based on the extracted image data of the achromatic region;
White balance adjustment means for performing white balance adjustment on the acquired image data based on the calculated gain adjustment value;
Program to function as.

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