JP2009044236A - White balance adjusting device and white balance adjusting method - Google Patents

Abstract

A white balance gain that does not cause a variation in color even when there is a slight deviation in the angle of view is calculated.
An image having no blur and an image having blur in the same shooting scene are obtained by continuously capturing a blur correction image and an increased blur image in a single release operation by a digital camera 1 having a blur correction function. To get. The blur-enhanced image is captured by operating the blur correction function in reverse. The blur-enhanced image is divided into a plurality of regions, and the integrated value of the image signal for each of R, G, and B in each divided region is captured, and a gain value for white balance adjustment is calculated. By using the calculated white balance gain, the white balance of the shake correction image is adjusted.
[Selection] Figure 4

Description

  The present invention relates to a white balance adjustment device and a white balance adjustment method, and more particularly to a white balance adjustment device and a white balance adjustment method for calculating an optimal white balance gain using a blurred image.

  Imaging with the imaging device is performed under various light sources such as a fluorescent lamp, an incandescent lamp, and sunlight. Since these light sources have different color temperatures, the same subject has different colors under the imaging environment. Conventionally, an imaging apparatus such as a digital camera has been provided with a white balance adjustment function that corrects the difference in color tone that varies depending on the light source and makes the white look the same regardless of the light source.

In Patent Document 1, a screen on which a subject is imaged is divided into a plurality of areas, color information for each divided area is obtained, and each area is detected based on the color information and indicates a color distribution range corresponding to a light source type. A white balance control method is described in which an appropriate white balance control is performed by discriminating a light source by applying to a frame and detecting the luminance level of an object and the amount of infrared light. According to this technique, it is possible to prevent a light source from being erroneously determined as a fluorescent lamp even in a low-luminance outdoor (shade) leafy green scene.
JP 2003-163944 A

  Here, a method described in Patent Document 1 for calculating a white balance gain by dividing a screen on which a subject is imaged into a plurality of areas will be described. FIGS. 17 and 18 are diagrams illustrating calculation of a white balance gain for dividing a captured image when a similar imaging scene is captured. FIG. 17A and FIG. 18A are diagrams showing captured images. Although the subject is the same, the angle of view is slightly different. FIG. 17B and FIG. 18B show how each captured image is divided into 3 × 3 blocks. In FIG. 17B, the subject is contained in one block E, but in FIG. 18B, the subject is spread over two blocks D and E.

  FIG. 17C and FIG. 18C show how the color average is calculated for each block. In FIG. 17B, the subject exists only in the block E. However, in FIG. 18B, the subject exists across the blocks D and E, so FIGS. 17C and 18C. , The colors of the block D and the block E are greatly changed.

  As described above, the white balance control method described in Patent Document 1 captures the same subject with the same light source because the integrated value of the divided blocks may change greatly even if there is a slight deviation in the angle of view. In spite of this, the calculated white balance gain also varies, and as a result, there is a disadvantage that hunting may occur in which the color of the white balance adjusted image varies. The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a white balance adjustment device and a white balance adjustment method capable of calculating an optimal white balance gain while preventing the integrated value of blocks from changing. And

  In order to achieve the above object, the white balance adjustment device according to claim 1, wherein an acquisition unit that acquires a non-blurred image and a blurred image in the same scene, and calculates a white balance gain from the blurred image And means for adjusting white balance of the unblurred image based on the white balance gain.

  As a result, it is possible to prevent hunting of the color of an image that has undergone white balance adjustment.

  According to a second aspect of the present invention, in the white balance adjusting apparatus according to the first aspect, the acquisition unit continuously captures an image with an imaging unit that converts the subject into image data and an exposure time in which blurring can be ignored. Means for performing control so that the overall exposure time is appropriate, first combining means for correcting and synthesizing the shift of the subject in the plurality of captured images, and shift of the subject in the plurality of captured images And a second synthesizing unit for synthesizing the image by increasing the image, wherein the first synthesizing unit generates a blur-free image, and the second synthesizing unit generates a blurred image.

  Thereby, it is possible to easily obtain a blur-free image and a blurred image.

  According to a third aspect of the present invention, in the white balance adjustment device according to the first aspect, the acquisition unit includes an imaging unit that converts a subject into image data, a detection unit that detects a shake of the apparatus body during imaging, and a correction. A moving unit that translates the lens or the image sensor, and a first control unit that performs the main imaging by translating the correction lens or the image sensor so as to correct blur based on the detection result of the detection unit; Based on the detection result of the detection means, the second control means for performing the main imaging by translating the correction lens or the imaging element so as to increase the blur, and the first control operation based on a single release operation. It is characterized in that a blur-free image is picked up by the control means and a blur-free image is picked up by the second control means.

  Thereby, it is possible to easily obtain a blur-free image and a blurred image.

  According to a fourth aspect of the present invention, in the white balance adjusting apparatus according to the second aspect, the second combining unit includes subjects in the plurality of captured images so that a blur amount of the blurred image is always constant. The shift is reduced, maintained, or increased to be synthesized.

  Thereby, a precise white balance gain can be calculated.

  According to a fifth aspect of the present invention, in the white balance adjustment device according to the third aspect, the second control unit is based on a detection result of the detection unit so that a blur amount of the blurred image is always constant. Then, the correction lens or the image sensor is moved in parallel so as to reduce, maintain, or increase the blur, and the main imaging is performed.

  Thereby, a precise white balance gain can be calculated.

  As described in claim 6, in the white balance adjustment device according to claim 2, the second combining means combines the subject images so that the object shifts in a plurality of directions. It is characterized in that blurring of an image with blurring is made in multiple directions.

  As a result, multi-directional hunting of the color of the image subjected to white balance adjustment can be prevented.

  According to a seventh aspect of the present invention, in the white balance adjusting device according to the third aspect, the second control unit translates the correction lens or the image sensor in a direction perpendicular to the detection result of the detection unit. Thus, blurring of the blurred image is made multi-directional.

  As a result, multi-directional hunting of the color of the image subjected to white balance adjustment can be prevented.

  In order to achieve the above object, the white balance adjustment device according to claim 8, an acquisition unit that acquires a blur-free image and a blurred image in the same scene, and detects a blur amount of the blurred image. A white balance comprising: a detection unit; a white balance gain calculation unit that calculates a white balance gain from the blurred image; and a unit that performs white balance adjustment of the image without blur based on the white balance gain. An adjustment device, wherein the white balance gain calculating means is a dividing means for dividing the blurred image into a plurality of areas, a means for calculating a white balance gain based on the image data of each divided area, When the amount of blur detected by the detecting means is appropriate, the image is divided more than when the amount of blur is not appropriate. And wherein the increasing the number of regions.

  Thereby, a precise white balance gain can be calculated.

  9. The white balance adjustment apparatus according to claim 8, wherein the acquisition unit includes an imaging unit that converts a subject into image data, a moving unit that translates a correction lens or an imaging element, and the detection. First correction means for performing main imaging by translating the correction lens or the image sensor so as to correct blur based on the detection result of the means, and so as to increase blur based on the detection result of the detection means. A second control unit that performs the main imaging by moving the correction lens or the imaging device in parallel, a non-blurred image capturing by the first control unit based on a single release operation, and the second An image with blur is picked up by the control means.

  Thereby, it is possible to easily obtain a blur-free image and a blurred image.

  In order to achieve the above object, a white balance adjustment method according to claim 10, wherein an acquisition step of acquiring a blur-free image and a blurred image in the same scene, and calculating a white balance gain from the blurred image And a step of adjusting the white balance of the image without blur based on the white balance gain.

  As a result, it is possible to prevent hunting of the color of an image that has undergone white balance adjustment.

  In order to achieve the object, the white balance adjustment method according to claim 11 acquires an unblurred image and a blurred image in the same scene, and detects a blur amount of the blurred image. A white balance adjustment comprising: a detecting step; a white balance gain calculating step of calculating a white balance gain from the blurred image; and a step of adjusting a white balance of the unblurred image based on the white balance gain. In the method, the white balance gain calculating step includes a dividing step of dividing the blurred image into a plurality of regions, and a step of calculating a white balance gain based on the image data of each divided region. When the amount of blur detected by the detection step is appropriate, the image is divided more than when the amount of blur is not appropriate. And wherein the increasing the frequency number.

  Thereby, a precise white balance gain can be calculated.

  According to the present invention, it is possible to provide a white balance adjustment device and a white balance adjustment method that can prevent variation in the integrated value of blocks and calculate an optimal white balance gain.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.

<First Embodiment>
FIG. 1 is a block diagram showing an electrical configuration of a first embodiment of a digital camera to which the present invention is applied.

  As shown in the figure, the digital camera 10 of the present embodiment includes a CPU 11, an operation unit 12, a zoom lens motor driver 13, a zoom lens 14, a focus lens motor driver 15, a focus lens 16, and a camera shake correction control unit. 17, camera shake correction lens 18, timing generator 19, CCD driver 20, CCD 21, analog signal processing unit 22, A / D converter 23, image input controller 24, image signal processing circuit 25, compression processing circuit 26, video encoder 27 , An image display device 28, a bus 29, a media controller 30, a recording medium 31, a memory (SDRAM) 32, an AF detection circuit 33, an AE detection circuit 34, and the like.

  Each unit operates under the control of the CPU 11, and the CPU 11 controls each unit of the digital camera 10 by executing a predetermined control program based on an input from the operation unit 12.

  The CPU 11 has a built-in program ROM, in which various data necessary for control are recorded in addition to the control program executed by the CPU 11. The CPU 11 controls each unit of the digital camera 10 by reading the control program recorded in the program ROM into the memory 32 and sequentially executing the program.

  The memory 32 is used as a program execution processing area, a temporary storage area for image data, and various work areas.

  The operation unit 12 includes general camera operation means such as a power switch, a release button, an imaging mode dial, and a camera shake correction switch, and outputs a signal corresponding to the operation to the CPU 11.

  The focus lens 16 is driven by the focus motor driver 15 to move back and forth on the optical axis of the zoom lens 14. The CPU 11 controls the movement of the focus lens 16 via the focus motor driver 15 to perform focusing.

  The zoom lens 14 is driven by the zoom lens motor driver 13 to move back and forth on the optical axis of the focus lens 16. The CPU 11 controls the movement of the zoom lens 14 via the zoom lens motor driver 13 to perform zooming.

  The camera shake correction lens 18 is controlled by the camera shake correction control unit 17 so as to cancel the camera shake in each of two orthogonal directions within the lens surface, and the camera shake of the subject image via the zoom lens 14 and the focus lens 16 is controlled. And the subject image after the camera shake correction is transmitted to the CCD 21.

  The CCD 21 is disposed after the camera shake correction lens 18 and receives subject light transmitted through the camera shake correction lens 18. As is well known, the CCD 21 has a light receiving surface on which a large number of light receiving elements are arranged in a matrix. The subject light transmitted through the camera shake correction lens 18 is imaged on the light receiving surface of the CCD 21 and converted into an electric signal by each light receiving element.

  The CCD 21 outputs the charge accumulated in each pixel as a serial image signal line by line in synchronization with the vertical transfer clock and horizontal transfer clock supplied from the timing generator 19 via the CCD driver 20. The CPU 11 controls the timing generator 19 to control the driving of the CCD 21.

  Note that the charge accumulation time (exposure time) of each pixel is determined by an electronic shutter drive signal given from the timing generator 19. The CPU 11 instructs the timing generator 19 on the charge accumulation time.

  The output of the image signal is started when the digital camera 10 is set to the imaging mode. That is, when the digital camera 10 is set to the imaging mode, output of an image signal is started to display a through image on the image display device 28. The output of the image signal for the through image is temporarily stopped when the instruction for the main imaging is performed, and is restarted when the main imaging is completed.

  The image signal output from the CCD 21 is an analog signal, and this analog image signal is taken into the analog signal processing unit 22.

  The analog signal processing unit 22 includes a correlated double sampling circuit (CDS) and an automatic gain control circuit (AGC). The CDS removes noise contained in the image signal, and the AGC amplifies the noise-removed image signal with a predetermined gain. The analog image signal subjected to the required signal processing by the analog signal processing unit 22 is taken into the A / D converter 23.

  The A / D converter 23 converts the captured analog image signal into a digital image signal having a gradation width of a predetermined bit. This image signal is so-called RAW data, and has a gradation value indicating the density of R, G, and B for each pixel.

  The image input controller 24 has a built-in line buffer with a predetermined capacity, and stores the image signal for one frame output from the A / D converter 23. The image signal for one frame accumulated in the image input controller 24 is stored in the memory 32 via the bus 29.

  In addition to the CPU 11, memory 32, and image input controller 24, the image signal processing circuit 25, compression processing circuit 26, video encoder 27, media controller 30, AF detection circuit 33, AE detection circuit 34, etc. are connected to the bus 29. These are configured to be able to transmit and receive information to and from each other via a bus 29.

  The image signal for one frame stored in the memory 32 is taken into the image signal processing circuit 25 in a dot sequence (pixel order).

  The image signal processing circuit 25 performs predetermined signal processing on the image signals of R, G, and B colors captured in a dot-sequential manner, and outputs an image signal (Y / C) composed of a luminance signal Y and color difference signals Cr, Cb Signal).

  FIG. 2 is a block diagram showing a schematic configuration of the image signal processing circuit 25.

  As shown in the figure, the image signal processing circuit 25 includes a white balance gain calculation circuit 25a, an offset correction circuit 25b, a gain correction circuit 25c, a gamma correction circuit 25d, an RGB interpolation operation circuit 25e, an RGB / YC conversion circuit 25f, noise. The filter 25g, the contour correction circuit 25h, the color difference matrix circuit 25i, the light source type determination circuit 25j, and the like are configured.

  As described above, the white balance gain calculation circuit 25a takes in the integrated value of the image signal for each of R, G, and B for each divided area divided into a plurality of areas, and calculates a gain value for white balance adjustment.

  The offset correction circuit 25b performs a predetermined offset process on the image signals of the R, G, and B colors fetched dot-sequentially from the RAM 44 so that black is expressed when a black subject is captured. That is, a preset offset value is subtracted from the image signals of R, G, and B colors.

  The gain correction circuit 25c captures the offset-processed image signal in a dot-sequential manner, and performs white balance adjustment using the gain value calculated by the white balance gain calculation circuit 25a.

  The gamma correction circuit 25d takes the image signal adjusted in white balance dot-sequentially and performs a predetermined gradation conversion process. That is, when the image data is output to the monitor, a deviation occurs between the gradation value input to the monitor and the gradation value output from the monitor. In order to correct this deviation, an image obtained by imaging is obtained. A predetermined gradation conversion process (so-called gamma correction) is performed on the signal.

  The RGB interpolation arithmetic circuit 25e interpolates R, G, and B color signals subjected to gradation conversion processing to obtain R, G, and B3 color signals at each pixel position. That is, in the case of a single-plate image sensor, each pixel outputs only a signal of any one color of R, G, and B. Therefore, a color that is not output is obtained from the color signals of surrounding pixels by a complementary operation. For example, in a pixel that outputs R, the level of G and B color signals at this pixel position is determined by interpolation from the G and B signals of surrounding pixels.

  Note that the RGB complementary calculation is unique to the single-plate image sensor, and thus is not necessary when a three-plate image sensor is used.

  The RGB / YC conversion circuit 25f generates a luminance signal Y and color difference signals Cr and Cb from the R, G, and B signals after the RGB interpolation calculation.

  The noise filter 25g performs noise reduction processing on the luminance signal Y and the color difference signals Cr and Cb generated by the RGB / YC conversion circuit 25f. The luminance signal Y and the color difference signals Cr and Cb that have been subjected to noise reduction processing by the noise filter 25g are taken into the contour correction circuit 25h and the color difference matrix circuit 25i, respectively.

  The color difference matrix circuit 25i performs color tone correction by multiplying the color difference signals Cr and Cb by a predetermined color difference matrix (C-MTX). That is, the color difference matrix circuit 25i is provided with a plurality of types of color difference matrices corresponding to the light sources. The color difference matrix to be used is switched according to the light source type obtained by the light source type determination circuit 25j, and the color difference matrix after the switching is displayed. The inputted color difference signals Cr and Cb are multiplied to correct the color tone of the color difference signals Cr and Cb.

  The light source type determination circuit 25j takes the integrated value calculated by the AE / AWB detection unit 36, determines the light source type, and outputs a color difference matrix selection signal to the color difference matrix circuit 25i.

  The contour correction circuit 25h performs a predetermined contour correction process on the luminance signal Y.

  As described above, the image signal processing circuit 25 performs predetermined signal processing on the R, G, and B image signals captured in a dot-sequential manner, and outputs an image signal (Y that includes the luminance signal Y and the color difference signals Cr and Cb). / C signal).

  The AF detection circuit 33 fetches R, G, B image signals stored in the memory 32 via the image input controller 24 in accordance with a command from the CPU 11 and calculates a focus evaluation value necessary for AF (Automatic Focus) control. . The AF detection circuit 33 includes a high-pass filter that passes only a high-frequency component of the G signal, an absolute value processing unit, a focus region extraction unit that extracts a signal within a predetermined focus region set on the screen, and a focus region An integration unit for integrating the absolute value data is included, and the absolute value data in the focus area integrated by the integration unit is output to the CPU 11 as a focus evaluation value. During the AF control, the CPU 11 searches for a position where the focus evaluation value output from the AF detection circuit 33 is maximized, and moves the focus lens 16 to that position, thereby performing focusing on the main subject.

  The AE detection circuit 34 takes in R, G, and B image signals stored in the memory 32 via the image input controller 24 in accordance with a command from the CPU 11 and calculates an integrated value necessary for AE control. The CPU 11 calculates a luminance value from the integrated value and obtains an exposure value from the luminance value. Further, the aperture value and the shutter speed are determined from the exposure value according to a predetermined program diagram.

  The compression processing circuit 26 performs compression processing of a predetermined format (for example, JPEG) on the input image signal (Y / C signal) composed of the luminance signal Y and the color difference signals Cr and Cb in accordance with the compression command from the CPU 11. Generate compressed image data. Further, in accordance with a decompression command from the CPU 11, the input compressed image data is subjected to decompression processing in a predetermined format to generate uncompressed image data.

  The video encoder 27 controls display on the image display device 28 in accordance with a command from the CPU 11.

  The media controller 30 controls reading / writing of data with respect to the recording medium 31 in accordance with a command from the CPU 11. The recording medium 31 may be detachable from the camera body such as a memory card, or may be built in the camera body. In the case of detachable, a card slot is provided in the camera body, and the card slot is used by being loaded.

  Next, the camera shake correction control unit 17 will be described. The digital camera 10 according to the present embodiment has a camera shake correction function, detects camera shake, and performs camera shake correction by moving a camera shake correction lens according to the camera shake. FIG. 3 is a block diagram illustrating the camera shake correction control unit 17 and the camera shake correction lens 18.

  The camera shake correction control unit 17 includes a position detection circuit 41, a yaw direction angular velocity sensor 42, a pitch direction angular velocity sensor 43, an angular velocity detection circuit 44, a camera shake correction control circuit 46, and a drive circuit 47. The camera shake correction lens 18 includes an X axis actuator 18a and a Y axis actuator 18b for moving the camera shake correction lens 18, and an X axis Hall element 18c and a Y axis Hall element for detecting the position of the camera shake correction lens 18. 18d.

  The angular velocity detection circuit 44 continuously detects the angular velocity of the digital camera 10 based on the outputs of the yaw direction angular velocity sensor 42 and the pitch direction angular velocity sensor 43.

  The camera shake correction control circuit 46 can drive the camera shake correction lens 18 by driving the X-axis actuator 18 a and the Y-axis actuator 18 b via the drive circuit 47. The position detection circuit 41 can detect the position of the camera shake correction lens 18 based on the outputs of the X-axis Hall element 18c and the Y-axis Hall element 18d. Based on the position information output from the position detection circuit 41, the camera shake correction control circuit 46 moves the camera shake correction lens 18 by a control amount corresponding to the angular velocity calculated by the angular velocity detection circuit 44, and performs camera shake correction. Do.

  Next, calculation of the white balance gain will be described. FIG. 4 is a flowchart showing the white balance gain calculation process, and FIG. 5 is a functional diagram showing the white balance adjustment process.

  First, a blur increase image is captured (step S41, processes P51 to P53). As described above, the digital camera 10 of the present embodiment has a camera shake correction function, and can capture an image that has undergone camera shake correction. Here, in a single release operation, together with the image subjected to the camera shake correction, images with increased blur are continuously captured, thereby obtaining a blur corrected image and an increased blur image in the same scene. As a means for capturing a blur-enhanced image, for example, the camera shake correction lens 18 may be moved in the blur direction by operating the camera shake correction function in reverse.

  Next, a white balance gain is calculated from the integrated value of the blur-enhanced image (step S42, process P55). As described above, the calculation of the white balance gain uses the integrated value of the image signal for each of R, G, and B for each divided region divided into a plurality of regions. FIGS. 6 and 7 are diagrams illustrating calculation of white balance gain using a blurred image when the angle of view is slightly different in the same imaging scene. FIG. 6A and FIG. 7A are diagrams showing blur correction images. Although it is the same shooting scene, the angle of view is slightly different. FIG. 6B and FIG. 7B are diagrams showing a blur-enhanced image captured subsequent to FIG. 6A and FIG. 7A, respectively. In the present embodiment, the blur correction function is operated so as to increase blur in the horizontal direction, and a blur increase image in the horizontal direction of the screen is captured.

  FIG. 6C and FIG. 7C show how each captured image is divided into 3 × 3 blocks. In both FIG. 6C and FIG. 7C, the subject extends over three blocks D, E, and F. FIG. 6D and FIG. 7D show how the color average is calculated for each block. 6 (c) and FIG. 7 (c), the subject exists across the three blocks D, E, and F. Therefore, comparing FIG. 6 (d) and FIG. 7 (d), the three blocks D are compared. The colors of the blocks E, F, and F are less likely to change abruptly, and it can be seen that the angle-of-view resistance is improved compared to the cases of FIGS.

  As described above, by using a blurred image, it is possible to calculate a white balance gain that does not cause color hunting even when the angle of view is slightly different.

  Next, the offset correction circuit 25b performs predetermined offset processing on the image signals of R, G, and B colors of the blur correction image (process P54), and the gain correction circuit 25c outputs the image signal subjected to the offset processing. The white balance adjustment is performed using the white balance gain value calculated as described above (process P56). The following signal processing is the same as described above (process P57).

  Even if the filter processing is used, a gain value similar to the white balance gain calculated in the present embodiment can be obtained. However, when the filter processing is performed, it takes a processing amount and processing time depending on the number of blocks. Can reduce the processing amount and processing time.

  In the present embodiment, the camera shake correction lens 18 is controlled to capture the camera shake correction image and the camera shake enhancement image. However, the method for obtaining these images is not limited to this method. May be controlled. In addition, a plurality of images are continuously captured with an exposure time in which blurring can be ignored, and the plurality of images are combined so as to correct the shift of the subject to generate a blur-corrected image. Then, the blur correction image and the blur increase image may be acquired by generating the blur increase image. In this case, the number of times of imaging is controlled so that the total exposure time of a plurality of images becomes an appropriate exposure time.

<Second Embodiment>
A digital camera 10 according to the second embodiment will be described. Similar to the first embodiment, the digital camera 10 according to the second embodiment has a blur correction function, and determines a blur amount so that the blur amount of the blur image is constant. 18 is controlled.

  FIG. 8 is a flowchart illustrating white balance gain calculation processing, and FIG. 9 is a functional diagram illustrating white balance adjustment processing.

  As in the first embodiment, a shake correction image and a blur image are continuously captured in a single release operation. First, a blur correction image is captured, and then the blur amount is measured (step S81, process P51, process P52). Then, the measured blur amount is determined (step S82, step S83). If it is determined that the amount of blur is small, the blur is increased by the camera shake correction function to capture a blur image (step S84, process P92, process P93). If it is determined that the amount of blur is large, the blur is reduced by the camera shake correction function to capture a blur image (step S85, process P92, process P93). If it is determined that the amount of blur is appropriate, the blur image is captured as it is without operating the camera shake correction function (step S86, process P92, process P93).

  Next, the white balance gain is calculated using the integrated value of the blurred image (step S42, process P55). The calculation of the white balance gain uses the integrated value of the image signal for each of R, G, and B for each divided area divided into a plurality of areas, as in the first embodiment.

  Next, the offset correction circuit 25b performs predetermined offset processing on the image signals of R, G, and B colors of the blur correction image (process P54), and the gain correction circuit 25c outputs the image signal subjected to the offset processing. The white balance adjustment is performed using the white balance gain value calculated as described above (process P56). The following signal processing is the same as described above (process P57).

  If the blur amount of the blurred image for calculating the white balance gain is too small, it is not possible to calculate an appropriate white balance gain that does not cause a variation in color. If the amount of blur is too large, the reliability as the integrated value is lowered. Therefore, the camera shake correction circuit performs control so that an appropriate shake amount is obtained. In addition, when blurring is appropriate, it is possible to capture an image with an appropriate blur amount and to reduce power consumption by stopping the blur correction function and capturing an image. Thus, by measuring the blur amount and controlling the camera shake correction function according to the blur amount, the blur amount of the blur image can be set to an appropriate blur amount, and as a result, hunting does not occur. The white balance gain can be calculated.

<Third Embodiment>
A digital camera 10 according to a third embodiment will be described. The digital camera 10 according to the third embodiment captures another direction blur image together with the blur correction image, and calculates the white balance gain using the other direction blur image.

  FIG. 10 is a flowchart illustrating the white balance gain calculation process, and FIG. 11 is a functional diagram illustrating the white balance adjustment process.

  As in the past, in a single release operation, a shake correction image and a shake image are continuously captured. First, the blur direction is measured (step S101, process P111), a blur correction image is captured (process P52), and imaging is performed by increasing the blur in a direction perpendicular to the measured blur direction (step S102, process P112, process P113).

  Next, the white balance gain is calculated using the integrated value of the blurred image (step S42, process P55). The calculation of the white balance gain uses the integrated value of the image signal for each of R, G, and B for each divided area divided into a plurality of areas as before.

  FIGS. 12, 13, and 14 are diagrams illustrating white balance gain calculation using a blurred image according to the present embodiment when the angle of view is slightly different in the same imaging scene. FIG. 12A, FIG. 13A, and FIG. 14A are diagrams illustrating a blur correction image. Although it is the same shooting scene, the angle of view is slightly different. FIGS. 12 (b), 13 (b), and 14 (b) show blur-enhanced images that are taken following FIGS. 12 (a), 13 (a), and 14 (a), respectively. FIG. In this example, when camera shake occurs in the horizontal direction of the screen, the shake correction function is reversely operated in the vertical direction of the screen.

  FIGS. 12C, 13C, and 14C show how each captured image is divided into 3 × 3 blocks. In any case, the subject extends over a plurality of vertical and horizontal blocks. 12 (d), 13 (d), and 14 (d) show how the color average is calculated for each block. In any case, since the subject exists across a plurality of blocks in the vertical and horizontal directions, the color of each block is hardly changed abruptly, and the angle of view tolerance is improved. As described above, by using a multi-directional blurred image, it is possible to calculate a white balance gain that is resistant to variations in hue in any direction.

  Once the white balance gain is calculated, the offset correction circuit 25b next performs a predetermined offset process on the image signals of the R, G, and B colors of the shake correction image (process P54), and the gain correction circuit 25c. The white balance adjustment is performed on the offset image signal using the white balance gain value calculated as described above (process P56). The following signal processing is the same as described above (process P57).

  As described above, by using the blurred image in the other direction as well as in one direction, it is possible to calculate an appropriate white balance gain that does not cause more variation in color.

<Fourth embodiment>
A digital camera 10 according to a fourth embodiment will be described. The digital camera 10 according to the fourth embodiment captures a blur image together with the blur correction image, and calculates a white balance gain by a method corresponding to the blur amount of the blur image.

  FIG. 15 is a flowchart showing the white balance gain calculation process, and FIG. 16 is a functional diagram showing the white balance adjustment process.

  As in the past, a shake correction image and a shake enhancement image are captured in a single release operation. First, a blur correction image is captured (process P52), and then an image with increased blur is captured (process S161). Then, the blur amount of the blur-enhanced image is measured (step S81, process P91).

  Next, a white balance gain calculation method is selected from the measured blur amount (process P162). First, it is determined whether or not the blur amount is appropriate (step S151). When the blur amount is appropriate, the white balance gain is calculated using the white balance gain calculation method [1] (step S152, process P55). If the amount of blur is not appropriate, the white balance gain is calculated using the white balance gain calculation method [2] (step S153, process P55).

  In [1] and [2] of the white balance gain calculation method, [1] has a larger number of screen divisions when obtaining an integrated value. Increasing the number of divisions improves white balance accuracy, but also tends to cause variations in color. However, by calculating the white balance gain using the blurred image, it is possible to prevent the occurrence of variations in hue, and therefore the number of divisions can be increased when the amount of blur is appropriate.

Once the white balance gain is calculated, the offset correction circuit 25b next performs a predetermined offset process on the image signals of the R, G, and B colors of the shake correction image (process P54), and the gain correction circuit 25c. The white balance adjustment is performed on the offset image signal using the white balance gain value calculated as described above (process P56). The following signal processing is the same as described above (process P57).
In this way, by switching the white balance gain calculation method according to the blur amount of the blur-enhanced image, a more accurate and appropriate white balance gain can be calculated.

FIG. 1 is a block diagram showing an electrical configuration of a first embodiment of a digital camera to which the present invention is applied. FIG. 2 is a block diagram showing a schematic configuration of the image signal processing circuit 25. FIG. 3 is a block diagram showing the inside of the camera shake correction control unit 17 and the camera shake correction lens 18. FIG. 4 is a flowchart showing the white balance gain calculation process. FIG. 5 is a functional diagram illustrating white balance adjustment processing. FIG. 6 is a diagram showing calculation of white balance gain using a blurred image. FIG. 7 is a diagram illustrating calculation of white balance gain using a blurred image. FIG. 8 is a flowchart showing the white balance gain calculation process. FIG. 9 is a functional diagram illustrating white balance adjustment processing. FIG. 10 is a flowchart showing the white balance gain calculation process. FIG. 11 is a functional diagram illustrating white balance adjustment processing. FIG. 12 is a diagram illustrating calculation of white balance gain using a blurred image. FIG. 13 is a diagram showing calculation of white balance gain using a blurred image. FIG. 14 is a diagram showing calculation of white balance gain using a blurred image. FIG. 15 is a flowchart illustrating white balance gain calculation processing. FIG. 16 is a functional diagram illustrating white balance adjustment processing. FIG. 17 is a diagram illustrating conventional white balance gain calculation. FIG. 18 is a diagram illustrating conventional white balance gain calculation.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Digital camera, 11 ... CPU, 12 ... Operation part, 17 ... Camera shake correction control part, 18 ... Camera shake correction lens, 21 ... CCD, 22 ... Analog signal processing part, 23 ... A / D converter, 24 ... Image input controller 25 ... Image signal processing circuit 25a ... White balance gain calculation circuit 25b ... Offset correction circuit 25c ... Gain correction circuit 25d ... Gradation correction circuit 25e ... RGB interpolation calculation circuit 25f ... RGB / YC Conversion circuit, 25g ... noise filter, 25h ... contour correction circuit, 25i ... color difference matrix circuit, 25j ... light source type determination circuit, 26 ... compression processing circuit, 32 ... memory, 33 ... AF detection circuit, 34 ... AE detection circuit

Claims (11)

An acquisition means for acquiring a blur-free image and a blurred image in the same scene;
Means for calculating a white balance gain from the blurred image;
Means for performing white balance adjustment of the image without blur based on the white balance gain;
A white balance adjustment device characterized by comprising: The acquisition means includes
Imaging means for converting a subject into image data;
Means for continuously performing imaging with an exposure time at which blurring can be ignored a plurality of times, and controlling so that the overall exposure time is appropriate;
First combining means for correcting and combining a shift of a subject in the plurality of captured images;
Second combining means for increasing and synthesizing a subject shift in the plurality of captured images,
2. The white balance adjusting apparatus according to claim 1, wherein a blur-free image is generated by the first combining unit, and a blurred image is generated by the second combining unit. The acquisition means includes
Imaging means for converting a subject into image data;
Detection means for detecting blurring of the apparatus main body during imaging;
Moving means for translating the correction lens or the image sensor;
First control means for performing main imaging by translating the correction lens or the imaging element so as to correct blur based on the detection result of the detection means;
Second control means for performing main imaging by translating the correction lens or the imaging element so that blurring increases based on the detection result of the detection means;
2. The blur-free image is picked up by the first control unit and the blur-free image is picked up by the second control unit based on a single release operation. White balance adjustment device.   The second combining unit combines the image by reducing, maintaining, or increasing a shift of a subject in the plurality of captured images so that a blur amount of the blurred image is always constant. 2. The white balance adjusting device according to 2.   The second control unit controls the correction lens or the image sensor to reduce, maintain, or increase blur based on the detection result of the detection unit so that the blur amount of the blurred image is always constant. The white balance adjustment device according to claim 3, wherein the white balance adjustment device performs parallel imaging to perform main imaging.   The second synthesizing unit synthesizes the blurring of the blurred image in multiple directions by synthesizing the plurality of captured images so that a subject shifts in multiple directions. The white balance adjustment device described in 1.   The second control unit is configured to shift the blur of the blurred image in multiple directions by translating the correction lens or the imaging element in a direction perpendicular to a detection result of the detection unit. The white balance adjustment device according to claim 3. An acquisition unit that acquires a blur-free image and a blurred image in the same scene, a detection unit that detects a blur amount of the blurred image, and a white balance gain that calculates a white balance gain from the blurred image A white balance adjustment device comprising: calculation means; and means for performing white balance adjustment of the image without blur based on the white balance gain,
The white balance gain calculating means includes:
Dividing means for dividing the blurred image into a plurality of regions;
Means for calculating a white balance gain based on the image data of each divided area,
2. A white balance adjusting device, wherein when the amount of blur detected by the detecting means is appropriate, the number of areas to be divided is increased as compared to when the amount of blur is not appropriate. The acquisition means includes
Imaging means for converting a subject into image data;
Moving means for translating the correction lens or the image sensor;
First control means for performing main imaging by translating the correction lens or the imaging element so as to correct blur based on the detection result of the detection means;
Second control means for performing main imaging by translating the correction lens or the imaging element so that blurring increases based on the detection result of the detection means;
9. The method according to claim 8, wherein a blur-free image is picked up by the first control unit and a blur-free image is picked up by the second control unit based on a single release operation. White balance adjustment device. An acquisition step of acquiring a blur-free image and a blurred image in the same scene;
Calculating a white balance gain from the blurred image;
Adjusting the white balance of the unblurred image based on the white balance gain;
A white balance adjustment method characterized by comprising: An acquisition step for acquiring a blur-free image and a blur image in the same scene, a detection step for detecting a blur amount of the blur image, and a white balance gain for calculating a white balance gain from the blur image A white balance adjustment method comprising: a calculation step; and a step of performing white balance adjustment of the image without blur based on the white balance gain,
The white balance gain calculation step includes:
A dividing step of dividing the blurred image into a plurality of regions;
A step of calculating a white balance gain based on the image data of each divided area,
A white balance adjustment method characterized in that when the amount of blur detected by the detection step is appropriate, the number of regions to be divided is increased as compared to when the amount of blur is not appropriate.

Images