JP5523213B2 - Imaging apparatus and imaging method - Google Patents

Description

  The present invention relates to a technique for correcting a difference between a pixel value of a Gr pixel and a pixel value of a Gb pixel, which is generated by ghost light or the like, with respect to image data obtained from an output of a solid-state imaging device having a Bayer array.

  When a subject with uniform brightness and color components is photographed by a Bayer array solid-state imaging device, a Gr signal that is a signal of a green filter pixel (Gr) in the R column and a green filter pixel (Gb) in the B column Should be the same as the Gb signal. However, there may be a signal difference (step) between the Gr signal and the Gb signal due to the difference in spectral characteristics between the green filter of the R row and the green filter of the B row and the influence of oblique incident light such as ghost light. . If a color image is generated while leaving this signal difference, a grid-like noise is generated on a uniform subject.

  Patent Document 1 discloses a technique for correcting a signal of a pixel of a green filter that is a processing target based on a signal of a pixel of a surrounding green filter. Patent Document 2 discloses a technique for changing characteristics when correcting a signal difference between a Gr signal and a Gb signal based on whether or not a target pixel is located at an edge portion. . Further, Patent Document 3 discloses a technique for correcting a signal difference by detecting a signal difference between a Gr signal and a Gb signal by comparing pixel data of a captured image with a reference pattern. .

JP 2001-218073 A JP 2005-311962 A JP 2005-333251 A

  However, in the technique described in Patent Document 1, since the signal of the pixel of the green filter is uniformly corrected, there arises a problem that the resolution of the fine edge portion is lowered. Further, with the technique described in Patent Document 2, a strong signal difference caused by ghost light or the like cannot be distinguished from a signal difference caused by a subject with a very fine edge on an image. Further, with the technique described in Patent Document 3, a subject with a very fine edge on an image is erroneously determined as a strong signal difference caused by ghost light or the like, and the signal value is corrected.

  It is an object of the present invention to provide a technique for correcting a strong signal difference caused by ghost light or the like by distinguishing and detecting a strong signal difference caused by ghost light or the like and a signal difference caused by a very fine edge subject. And

An imaging device according to an aspect of the present invention includes a line in which R pixels and Gr pixels are alternately arranged in the horizontal direction and a line in which B pixels and Gb pixels are alternately arranged in the horizontal direction alternately in the vertical direction. An image pickup apparatus having a solid-state image sensor having a Bayer array structure to be arranged, and image data obtained from an output of the solid-state image sensor is included in the image area for each image area composed of a predetermined number of pixels. An average pixel value calculation unit that calculates a Gr average pixel value that is an average value of pixel values of Gr pixels and calculates a Gb average pixel value that is an average value of pixel values of Gb pixels included in the image region; and the Gr average A correction determination unit that determines whether to correct the pixel value of the Gr pixel and the pixel value of the Gb pixel based on the pixel value and the Gb average pixel value, and the correction determination unit Wherein if it is determined that corrects, and a correcting unit that corrects the pixel value and the pixel value of the Gb pixel of the Gr pixel, the correction determining unit, and the Gr average pixel value for each said image region If the difference value with the Gb average pixel value is calculated and the calculated difference value is equal to or greater than the first threshold value, the difference value is cumulatively added, and the value obtained by cumulatively adding the difference value is greater than the first threshold value. When it is equal to or larger than the second large threshold value, it is determined that the pixel value of the Gr pixel and the pixel value of the Gb pixel are corrected.
The imaging apparatus according to another aspect of the present invention includes a line in which R pixels and Gr pixels are alternately arranged in the horizontal direction and a line in which B pixels and Gb pixels are alternately arranged in the horizontal direction. An image pickup apparatus having a Bayer array structure solid-state image pickup device alternately arranged in each of the image regions obtained from the output of the solid-state image pickup device for each image region composed of a predetermined number of pixels. An average pixel value calculation unit that calculates a Gr average pixel value that is an average value of pixel values of Gr pixels included in the image area, and calculates a Gb average pixel value that is an average value of pixel values of Gb pixels included in the image area; A correction determination unit that determines whether to correct a pixel value of the Gr pixel and a pixel value of the Gb pixel based on the Gr average pixel value and the Gb average pixel value; and the correction determination unit Accordingly, when it is determined that correction is to be performed, the correction unit corrects the pixel value of the Gr pixel and the pixel value of the Gb pixel, and the correction unit is located around the Gr pixel that is the processing target pixel The pixel value of the Gr pixel that is the processing target pixel is corrected based on the pixel value of the Gb pixel, and the processing target pixel is based on the pixel value of the Gr pixel that is located around the Gb pixel that is the processing target pixel. The pixel value of the Gb pixel is corrected.

Imaging device according to still another aspect of the present invention, a line of R pixels and Gr pixels are arranged alternately in the horizontal direction, and a line B pixel and Gb pixel in the horizontal direction are alternately arranged in the vertical direction An image pickup apparatus having a solid-state image pickup device having a Bayer array structure arranged alternately, wherein image data obtained from an output of the solid-state image pickup device is arranged in the image region for each image region composed of a predetermined number of pixels. An average pixel value calculation unit that calculates a Gr average pixel value that is an average value of pixel values of Gr pixels included, and calculates a Gb average pixel value that is an average value of pixel values of Gb pixels included in the image region; Correction for calculating a correction amount for correcting the pixel value of the Gr pixel and the pixel value of the Gb pixel based on the Gr average pixel value and the Gb average pixel value for each image region A calculating unit, for each of the image areas, based on the correction amount calculated in the correction amount calculation unit, and a correcting unit for correcting the pixel value of the Gr pixel and Gb pixel in the image area, the correction The amount calculation unit calculates a difference value between the Gr average pixel value and the Gb average pixel value for each image region, and sets the correction amount to 0 when the calculated difference value is smaller than a first predetermined value, When the difference value is greater than or equal to a second predetermined value greater than the first predetermined value, the correction amount is set as a maximum correction amount, the difference value is greater than or equal to the first predetermined value, and the second When the difference value is smaller than the predetermined value, the correction amount is increased monotonically between 0 and the maximum correction amount as the difference value increases.
In addition, in an imaging device according to still another aspect of the present invention, a line in which R pixels and Gr pixels are alternately arranged in the horizontal direction and a line in which B pixels and Gb pixels are alternately arranged in the horizontal direction are vertical. An image pickup apparatus having a Bayer array structure solid-state image pickup device alternately arranged in a direction, wherein the image data obtained from the output of the solid-state image pickup device for each image region composed of a predetermined number of pixels An average pixel value calculation unit that obtains a Gr average pixel value that is an average value of pixel values of Gr pixels included in the region and calculates a Gb average pixel value that is an average value of pixel values of the Gb pixels included in the image region; For each of the image regions, a correction amount for correcting the pixel value of the Gr pixel and the pixel value of the Gb pixel is calculated based on the Gr average pixel value and the Gb average pixel value. A correction amount calculation unit; and a correction unit that corrects the pixel values of the Gr pixel and the Gb pixel in the image region based on the correction amount calculated by the correction amount calculation unit for each image region, The correction amount calculated by the correction amount calculation unit is a correction coefficient, and the correction unit is located around the pixel value of the Gr pixel and the Gr pixel when the processing target pixel is a Gr pixel. The pixel value of the Gb pixel is subjected to weighted average addition based on the correction coefficient, and when the pixel to be processed is a Gb pixel, the pixel value of the Gb pixel and the pixel value of the Gr pixel located around the Gb pixel are calculated. The pixel values of the Gr pixel and Gb pixel are corrected by performing weighted average addition based on the correction coefficient.

In the imaging method according to still another aspect of the present invention, a line in which R pixels and Gr pixels are alternately arranged in the horizontal direction and a line in which B pixels and Gb pixels are alternately arranged in the horizontal direction are arranged in the vertical direction. An imaging method using an imaging device having alternately arranged Bayer array structure solid-state image sensors, wherein the image data obtained from the output of the solid-state image sensor for each image region composed of a predetermined number of pixels Obtaining a Gr average pixel value which is an average value of pixel values of Gr pixels included in the image area, and obtaining a Gb average pixel value which is an average value of pixel values of Gb pixels included in the image area; Determining whether to correct the pixel value of the Gr pixel and the pixel value of the Gb pixel based on the Gr average pixel value and the Gb average pixel value; If it is determined to perform, the includes a step of correcting the pixel value and the pixel value of the Gb pixel of the Gr pixel, the said at determining whether or not to correct, the Gr average pixel value for each said image region And the Gb average pixel value is calculated, and if the calculated difference value is equal to or greater than a first threshold value, the difference value is cumulatively added, and the value obtained by cumulatively adding the difference value is the first threshold value. When the value is equal to or larger than the second threshold value, the pixel value of the Gr pixel and the pixel value of the Gb pixel are determined to be corrected.
In addition, in the imaging method according to another aspect of the present invention, a line in which R pixels and Gr pixels are alternately arranged in the horizontal direction and a line in which B pixels and Gb pixels are alternately arranged in the horizontal direction are vertical. An imaging method using an imaging device having a solid-state imaging device having a Bayer array structure alternately arranged in a direction, and an image region composed of a predetermined number of pixels for image data obtained from the output of the solid-state imaging device For each step, a Gr average pixel value that is an average value of pixel values of Gr pixels included in the image area and a Gb average pixel value that is an average value of pixel values of Gb pixels included in the image area are obtained. Determining whether to correct the pixel value of the Gr pixel and the pixel value of the Gb pixel based on the Gr average pixel value and the Gb average pixel value; If it is determined that correction is to be performed, the pixel value of the Gr pixel and the pixel value of the Gb pixel are corrected. In the correction step, the Gb pixel positioned around the Gr pixel that is the processing target pixel is included. Based on the pixel value, the pixel value of the Gr pixel that is the processing target pixel is corrected, and based on the pixel value of the Gr pixel that is located around the Gb pixel that is the processing target pixel, the processing target pixel Gb The pixel value of the pixel is corrected.

In the imaging method according to still another aspect of the present invention, a line in which R pixels and Gr pixels are alternately arranged in the horizontal direction and a line in which B pixels and Gb pixels are alternately arranged in the horizontal direction are arranged in the vertical direction. An imaging method using an imaging device having alternately arranged Bayer array structure solid-state image sensors, wherein the image data obtained from the output of the solid-state image sensor for each image region composed of a predetermined number of pixels Obtaining a Gr average pixel value which is an average value of pixel values of Gr pixels included in the image area, and obtaining a Gb average pixel value which is an average value of pixel values of Gb pixels included in the image area; For each image area, a correction amount for correcting the pixel value of the Gr pixel and the pixel value of the Gb pixel is calculated based on the Gr average pixel value and the Gb average pixel value. A step that, for each of said image regions, on the basis of the correction amount, and a step of correcting the pixel value of the Gr pixel and Gb pixel in the image area, in the step of calculating the correction amount, the image A difference value between the Gr average pixel value and the Gb average pixel value is calculated for each region, and when the calculated difference value is smaller than a first predetermined value, the correction amount is set to 0, and the difference value is the first value. When the second predetermined value is greater than the second predetermined value, the correction amount is set as the maximum correction amount, and the difference value is equal to or larger than the first predetermined value and smaller than the second predetermined value. Increases the correction amount monotonically between 0 and the maximum correction amount as the difference value increases.
In addition, in the imaging method according to another aspect of the present invention, a line in which R pixels and Gr pixels are alternately arranged in the horizontal direction and a line in which B pixels and Gb pixels are alternately arranged in the horizontal direction are vertical. An imaging method using an imaging device having a solid-state imaging device having a Bayer array structure alternately arranged in a direction, and an image region composed of a predetermined number of pixels for image data obtained from the output of the solid-state imaging device For each step, a Gr average pixel value that is an average value of pixel values of Gr pixels included in the image area and a Gb average pixel value that is an average value of pixel values of Gb pixels included in the image area are obtained. And a correction amount for correcting the pixel value of the Gr pixel and the pixel value of the Gb pixel based on the Gr average pixel value and the Gb average pixel value for each image region And a step of correcting pixel values of Gr pixels and Gb pixels in the image region based on the correction amount for each image region, and the correction amount is a correction coefficient, In the correcting step, when the processing target pixel is a Gr pixel, the pixel value of the Gr pixel and the pixel value of a Gb pixel located around the Gr pixel are weighted and averaged based on the correction coefficient. When the pixel to be processed is a Gb pixel, the pixel value of the Gb pixel and the pixel value of the Gr pixel located around the Gb pixel are weighted and averaged based on the correction coefficient, whereby the Gr pixel and The pixel value of the Gb pixel is corrected.

  According to the present invention, an unnecessary step caused by ghost light or the like among the steps between the pixel value of the Gr pixel and the pixel value of the Gb pixel can be corrected.

It is a block diagram which shows the structure of the digital still camera which is an imaging device in 1st Embodiment. It is a figure which shows the detailed structure of an image process part. It is a flowchart which shows the flow of the process performed by the image process part. It is a figure for demonstrating the method of averaging the Gr pixel and the average of a Gb pixel within the area | region of 40 pixels x 40 pixels which is an area | region of predetermined magnitude | size. Gr average filter processing and Gb average filter processing are performed within an area of 40 pixels × 40 pixels that is a predetermined size area, and the obtained Gr average pixel value and Gb average pixel value are stored in the reduced image memory It is a figure which shows the process to be made. 10 is a flowchart showing detailed contents of a level difference detection process performed by a level difference detection unit 1053. FIG. 7A is a diagram for explaining a method of correcting the pixel value of the Gb pixel that is the processing target pixel based on the pixel values of the four Gr pixels that are located around the Gb pixel that is the processing target pixel. FIG. 7B illustrates a method of correcting the pixel value of the Gr pixel that is the processing target pixel based on the pixel values of the four Gb pixels that are located around the Gr pixel that is the processing target pixel. FIG. It is a figure for demonstrating the Gr signal value and Gb signal value when a ghost light generate | occur | produces. It is a figure for demonstrating the Gr signal value and Gb signal value in case a very fine edge exists in an image. It is a figure which shows the detailed structure of the image process part of the imaging device in 2nd Embodiment. It is a flowchart which shows the flow of the process performed by the image process part in 2nd Embodiment. It is a flowchart which shows the detail of the process which produces a correction coefficient map. It is a figure which shows the relationship between the relative difference value D and the correction coefficient (alpha). FIG. 14A is a diagram showing an example of an object with very fine edges and an image with ghost light, and FIG. 14B is created based on the image shown in FIG. It is a figure which shows the corrected correction coefficient map.

<First Embodiment>
FIG. 1 is a block diagram illustrating a configuration of a digital still camera that is an imaging apparatus according to the first embodiment.

  The lens 101 condenses the optical image of the subject on the image sensor 102. The lens 101 may be a single focus lens or a zoom lens.

  The lens drive control circuit 112 issues a command to drive the lens 101 to the lens drive unit 111 based on a focus evaluation value calculated by the microcomputer 107 described later. The lens driving unit 111 drives the lens 101 based on an instruction from the lens driving control circuit 112 to change the focal length and the focus position.

  The image sensor 102 is an image sensor in which a Bayer array color filter is arranged in front of a photodiode constituting each pixel. The Bayer array has lines in which red and green filters are alternately arranged in the horizontal direction and lines in which green and blue filters are alternately arranged, and the two lines are also alternately arranged in the vertical direction. It is composed by arranging. In this specification, a pixel of a red (Red) filter is an R pixel, a pixel of a green (Green) filter, a pixel adjacent to the R pixel in the horizontal direction is a Gr pixel, a pixel of a blue (Blue) filter is a B pixel, Among the pixels of the green filter, a pixel adjacent to the B pixel in the horizontal direction is referred to as a Gb pixel. The imaging element 102 outputs the amount of light to the imaging circuit 103 as a charge amount by receiving and photoelectrically converting the light collected by the lens 101 by a photodiode constituting the pixel. The image sensor 102 may be a CMOS type or a CCD type.

  The imaging circuit 103 performs waveform shaping on the electrical signal (analog image signal) read from the imaging element 102 while reducing reset noise and the like, and further increases the gain so that the target brightness is obtained. The A / D converter 104 converts the analog image signal output from the imaging circuit 103 into a digital image signal (hereinafter referred to as image data).

  A bus 199 is a transfer path for transferring various data generated in the digital camera to each unit in the digital camera. The bus 199 is connected to the A / D converter 104, the image processor 105, the JPEG processor 106, the microcomputer 107, the SDRAM 108, the memory I / F 109, and the LCD driver 110.

  The image data output from the A / D conversion unit 104 is temporarily stored in the SDRAM 108 via the bus 199. The SDRAM 108 is a storage unit that temporarily stores various data such as image data obtained by the A / D conversion unit 104 and image data processed by the image processing unit 105 and the JPEG processing unit 106.

  The image processing unit 105 performs various image processing such as optical black subtraction processing, white balance correction processing, synchronization processing, gamma correction processing, and color reproduction processing on the image data read from the SDRAM 108. The image processing unit 105 also corrects an unnecessary signal difference (step) between the signal value of the Gr pixel and the signal value of the Gb pixel.

  When the image data is recorded, the JPEG processing unit 106 reads the image data from the SDRAM 108, compresses the read image data according to the JPEG compression method, and temporarily stores the compressed JPEG image data in the SDRAM 108. The microcomputer 107 creates a JPEG file by adding a JPEG header necessary for constructing a JPEG file to the JPEG image data stored in the SDRAM 108, and sends the created JPEG file via the memory I / F 109. To the recording medium 115. The recording medium 115 is, for example, a recording medium including a memory card that can be attached to and detached from the camera body, but is not limited thereto.

  The LCD driver 110 displays an image on the LCD 116. For image display, rec view display that displays image data immediately after shooting for a short time, playback display of a JPEG file recorded on the recording medium 115, and display of moving images such as a live view image (also referred to as a through image). Is included. Also, when playing back a JPEG file recorded on the recording medium 115, the JPEG processing unit 106 reads the JPEG file recorded on the recording medium 115 and performs expansion processing, and then temporarily expands the expanded image data to the SDRAM 108. Remember me. The LCD driver 110 reads the decompressed image data from the SDRAM 108, converts the read image data into a video signal, and then outputs it to the LCD 116 to display an image.

  The microcomputer 107 having a function as a control unit comprehensively controls various sequences of the digital camera body. The microcomputer 107 is connected to a lens drive control circuit 112, an operation unit 113, and a flash memory 114.

  The operation unit 113 is an operation member such as a power button, a release button, and various input keys. When one of the operation members of the operation unit 113 is operated by the user, the microcomputer 107 executes various sequences according to the user's operation. The power button is an operation member for instructing power on / off of the digital camera. When the power button is pressed, the microcomputer 107 turns on or off the power of the digital camera. The release button has a two-stage switch of a first release switch and a second release switch. When the release button is pressed halfway and the first release switch is turned on, the microcomputer 107 performs a shooting preparation sequence such as AE processing and AF processing. When the release button is fully pressed and the second release switch is turned on, the microcomputer 107 performs shooting by executing a shooting sequence.

  The flash memory 114 stores various parameters necessary for the operation of the digital camera such as a white balance gain and a low-pass filter coefficient corresponding to the white balance mode. The flash memory 114 also stores various programs executed by the microcomputer 107. The microcomputer 107 reads parameters necessary for various sequences from the flash memory 114 according to a program stored in the flash memory 114, and executes each process.

  FIG. 2 is a diagram illustrating a detailed configuration of the image processing unit 105. The image processing unit 105 includes a low-pass filter unit 1051 (hereinafter referred to as an LPF unit 1051), a reduced image memory 1052, a step detection unit 1053, a control unit 1054, a step correction unit 1055, and a synthesis unit 1056. Prepare.

  The LPF unit 1051 reads the image data from the SDRAM 108, and averages the pixel values of the Gr pixel and the Gb pixel for each area of a predetermined size of the read image data. Here, the pixel values of the Gr pixel and the Gb pixel obtained by the averaging process are referred to as a Gr average pixel value and a Gb average pixel value, respectively. The Gr average pixel value and the Gb average pixel value are stored in the reduced image memory 1052.

  Based on the Gr average pixel value and the Gb average pixel value recorded in the reduced image memory 1052, the level difference detection unit 1053 performs a Gr pixel signal (hereinafter referred to as a Gr signal) and a Gb pixel signal (hereinafter referred to as a Gb signal). The step (signal difference) is detected.

  The control unit 1054 instructs the step correction unit 1055 whether or not to correct the step between the Gr signal and the Gb signal based on the step detection result by the step detection unit 1053.

  The level difference correction unit 1055 corrects the pixel values of the Gr pixel and the Gb pixel of the image data read from the SDRAM 108 based on a correction instruction from the control unit 1054. However, when an instruction for no correction is received from the control unit 1054, the step correction unit 1055 outputs the image data read from the SDRAM 108 to the synthesis unit 1056 as it is.

  The synthesizing unit 1056 performs a demosaicing process for generating image data including R, G, and B information per pixel from image data (Bayer image data) based on a Bayer array.

  FIG. 3 is a flowchart showing a flow of processing performed by the image processing unit 105. In step S <b> 10, the LPF unit 1051 reads image data (Bayer image data) output from the A / D conversion unit 104 and temporarily stored in the SDRAM 108 from the SDRAM 108.

  In step S20, the LPF unit 1051 averages the pixel values of the Gr pixel and the Gb pixel for each region of a predetermined size of the image data read from the SDRAM 108, and obtains the Gr average pixel value and the Gb average pixel value. The image is stored in the reduced image memory 1052. The predetermined size region is a range that does not exceed the size of the ghost light appearing in the image, and is a size that does not sufficiently show the fine edge structure by averaging. This is an area of pixels × 40 pixels.

  FIG. 4 is a diagram for explaining a method of performing averaging of Gr pixels and averaging of Gb pixels within a region of 40 pixels × 40 pixels that is a region having a predetermined size. As shown in FIG. 4, Gr averaging filter processing for reading all Gr pixels within 40 pixels × 40 pixels and calculating the average of the pixel values of all the read Gr pixels, and Gb pixels within 40 pixels × 40 pixels And Gb averaging filter processing for obtaining the average of the pixel values of all the read Gb pixels.

  FIG. 5 shows that a Gr average filter process and a Gb average filter process are performed in an area of 40 pixels × 40 pixels, which is a predetermined size area, and the obtained Gr average pixel value and Gb average pixel value are reduced. It is a figure which shows the process memorize | stored in the image memory. The Gr average pixel value obtained by the Gr averaging filter process and the Gb average pixel value obtained by the Gb average filter process are respectively stored in the reduced image memory 1052.

  In step S30, the level difference detection unit 1053 detects the presence or absence of a level difference between the Gr signal and the Gb signal due to ghost light or the like. The step detection process performed by the step detection unit 1053 will be described with reference to the flowchart shown in FIG.

  In step S100 of the flowchart shown in FIG. 6, the first region (first processing target region) among the Gr average pixel value and Gb average pixel value for each region of a predetermined size stored in the reduced image memory 1052. The Gr average pixel value and the Gb average pixel value corresponding to are read out.

  In step S110, the relative difference value D is calculated based on the Gr average pixel value and the Gb average pixel value from the following equation (1). As shown in the following equation (1), the relative difference value D is a value obtained by dividing the difference value between the Gr average pixel value and the Gb average pixel value by the average value of the Gr average pixel value and the Gb average pixel value. is there.

D = 2 × (Gr−Gb) / (Gr + Gb) (1)
In step S120, it is determined whether or not the relative difference value D calculated in step S110 is greater than or equal to the first threshold value D1. The first threshold D1 is a threshold for removing noise. If it is determined that the relative difference value D is greater than or equal to the first threshold value D1, the process proceeds to step S130. If it is determined that the relative difference value D is less than the first threshold value D1, the process proceeds to step S140.

  In step S130, the relative difference value D calculated in step S110 is added to the step counter. The step counter is a counter provided inside the step detection unit 1053, and is reset to 0, which is an initial value, when the processing of the flowchart shown in FIG. 6 is started.

  In step S140, it is determined whether or not the processing from step S110 to step S130 has been performed on the entire area of the image data. If it is determined that the processing for all areas of the image data has not been completed, the process proceeds to step S150.

  In step S150, the Gr average pixel value and the Gb average pixel value corresponding to the next processing target area are read from the reduced image memory 1052, and the process proceeds to step S110 to perform the processes from step S110 to step S130. Thereby, the value of the relative difference value D calculated for each region having a predetermined size is cumulatively added to the step counter.

  On the other hand, if it is determined in step S140 that the processing for all areas of the image data has been completed, the process proceeds to step S160. In step S160, it is determined whether or not the cumulative value of the relative difference value D added to the step counter (hereinafter referred to as the cumulative relative difference) is equal to or greater than the second threshold value D2. The second threshold value D2 is a threshold value for determining whether or not there is a step between the Gr signal and the Gb signal due to ghost light or the like, and is a value larger than the first threshold value D1. If it is determined that the accumulated relative difference is greater than or equal to the second threshold value D2, the process proceeds to step S170, and if it is determined that the cumulative relative difference is less than the second threshold value D2, the process proceeds to step S180.

  In step S170, it is determined that there is a step between the Gr signal and the Gb signal due to ghost light or the like. On the other hand, in step S180, it is determined that there is no step between the Gr signal and the Gb signal due to ghost light or the like.

  Returning to the flowchart shown in FIG. In step S40, the control unit 1054 determines whether or not there is a step between the Gr signal and the Gb signal due to ghost light or the like based on the result of the step detection process by the step detection unit 1053. When determining that there is a step, the control unit 1054 outputs a correction instruction to the step correction unit 1055 and proceeds to step S50. When determining that there is no step, the control unit 1054 outputs an instruction without correction to the step correction unit 1055 and proceeds to step S60.

  In step S50, the level difference correction unit 1055 reads Bayer image data from the SDRAM 108 based on a correction instruction from the control unit 1054, and corrects the pixel values of the Gr pixel and the Gb pixel.

  FIG. 7A is a diagram for explaining a method of correcting the pixel value of the Gb pixel that is the processing target pixel based on the pixel values of the four Gr pixels that are located around the Gb pixel that is the processing target pixel. It is. The pixel value of the Gb pixel after correction is expressed by the following equation (2). In Equation (2), the corrected Gb is the pixel value of the corrected Gb pixel, the uncorrected Gb is the pixel value of the Gb pixel before correction, and the surrounding Gr1 to Gr4 are the Gb pixels that are the processing target pixels. The pixel values of the four Gr pixels located around are shown.

Gb after correction = Gb before correction × (1/2) + (peripheral Gr1 + peripheral Gr2 + peripheral Gr3 + peripheral Gr4) × (1/8) (2)
FIG. 7B is a diagram for explaining a method of correcting the pixel value of the Gr pixel that is the processing target pixel based on the pixel values of the four Gb pixels that are located around the Gr pixel that is the processing target pixel. It is. The pixel value of the Gr pixel after correction is expressed by the following equation (3). In equation (3), the corrected Gr is the pixel value of the corrected Gr pixel, the uncorrected Gr is the pixel value of the Gr pixel before correction, and the surrounding Gb1 to Gb4 are the Gr pixels that are the processing target pixels. The pixel values of four Gb pixels located in the periphery are respectively shown.

Gr after correction = Gr before correction × (1/2) + (peripheral Gb1 + peripheral Gb2 + peripheral Gb3 + peripheral Gb4) × (1/8) (3)
The pixel values of the Gr pixel and the Gb pixel are corrected for all the Gr pixels and Gb pixels in the Bayer image data.

  In step S60, the synthesizing unit 1056 performs a demosaicing process for generating image data including R, G, and B information per pixel from the Bayer image data.

  FIG. 8 is a diagram for explaining the Gr signal value and the Gb signal value when ghost light is generated. FIG. 8A is a diagram showing a region 80 where ghost light is generated on the image and a region 81 of 40 pixels × 40 pixels which is a region of a predetermined size. FIG. 8B is a diagram showing a Gr signal value (pixel value of Gr pixel) and a Gb signal value (pixel value of Gb pixel) in a region 81 having a predetermined size.

  As shown in FIG. 8B, a step is generated between the Gr signal value and the Gb signal value in the region where the ghost light is generated. In this case, since the difference between the Gr average pixel value and the Gb average pixel value is large, the cumulative relative difference described above is equal to or greater than the second threshold D2, and there is a step between the Gr signal and the Gb signal due to ghost light or the like. Then, it is determined. Accordingly, the pixel value correction described above is performed for all Gr pixels and Gb pixels in the Bayer image data.

  FIG. 9 is a diagram for explaining the Gr signal value and the Gb signal value when a subject having very fine edges exists in the image. FIG. 9A is a diagram showing an example of an image in which a subject 92 having a very fine edge exists in a region 91 of 40 pixels × 40 pixels that is a region of a predetermined size. FIG. 9B is a diagram showing Gr signal values and Gb signal values in a region 91 having a predetermined size. In this case, there are a portion where the Gr signal value is larger than the Gb signal value and a portion where the Gb signal value is larger than the Gr signal value depending on the structure of the edge, so that the Gr average pixel value and the Gb average pixel value are substantially equal. Therefore, the cumulative relative difference described above is less than the second threshold value D2, and it is determined that there is no step between the Gr signal and the Gb signal due to ghost light or the like. That is, the correction of the pixel values of the Gr pixel and the Gb pixel in the Bayer image data is not performed.

  As described above, according to the imaging device in the first embodiment, for the image data obtained from the output of the solid-state imaging device, the pixel value of the Gr pixel included in the image region is determined for each image region composed of a predetermined number of pixels. A Gr average pixel value that is an average value is obtained, a Gb average pixel value that is an average value of pixel values of Gb pixels included in the image region is obtained, and based on the obtained Gr average pixel value and the Gb average pixel value, Gr It is determined whether or not to correct the pixel value of the pixel and the pixel value of the Gb pixel. If it is determined that correction is to be performed, the pixel value of the Gr pixel and the pixel value of the Gb pixel are corrected, so that a strong step caused by ghost light and the like and a step caused by a subject with a very fine edge are distinguished and detected. When there is a strong step caused by ghost light or the like, the step can be corrected. That is, it is possible to prevent erroneous correction of the pixel values of the Gr pixel and the Gb pixel with respect to image data in which ghost light is not generated and a subject with a very fine edge exists.

  In particular, the difference value between the Gr average pixel value and the Gb average pixel value is calculated for each image area, and if the calculated difference value is equal to or greater than the first threshold value, the difference value is cumulatively added and the difference value is cumulatively added. When the value is equal to or greater than a second threshold value that is greater than the first threshold value, it is determined that the pixel value of the Gr pixel and the pixel value of the Gb pixel are to be corrected. As a result, a strong step caused by ghost light or the like can be detected by reliably distinguishing it from a step caused by a subject with a very fine edge.

  Further, based on the pixel value of the Gb pixel located around the Gr pixel of the processing target pixel, the pixel value of the Gr pixel of the processing target pixel is corrected, and the Gr pixel located around the Gb pixel of the processing target pixel is corrected. Since the pixel value of the Gb pixel of the processing target pixel is corrected based on the pixel value, the step can be corrected effectively.

<Second Embodiment>
FIG. 10 is a diagram illustrating a detailed configuration of the image processing unit 105A of the imaging apparatus according to the second embodiment. Of the configuration of the image processing unit 105A illustrated in FIG. 10, the same configuration as the configuration of the image processing unit 105 illustrated in FIG.

  In the image processing unit 105A in the second embodiment, the control unit 1054 is deleted and a correction coefficient map memory 1057 is added to the image processing unit 105 in the first embodiment. Further, since the processing performed internally is different from that of the first embodiment, the reference numerals of the step detection unit and the step correction unit are 1053A and 1055A, respectively.

  The correction coefficient map memory 1057 stores correction coefficients for correcting the pixel values of the Gr pixel and the Gb pixel for each region having a predetermined size.

  FIG. 11 is a flowchart showing a flow of processing performed by the image processing unit 105A in the second embodiment. Steps in which the same processing as that in the flowchart shown in FIG. 3 is performed are denoted by the same reference numerals, and detailed description thereof is omitted.

  In step S1100 following step S20, the level difference detection unit 1053A creates a correction coefficient map. Details of the process of creating the correction coefficient map will be described with reference to the flowchart shown in FIG.

  In step S1200 of the flowchart shown in FIG. 12, among the Gr average pixel value and Gb average pixel value for each area of a predetermined size stored in the reduced image memory 1052, the first area (first processing target area). The Gr average pixel value and the Gb average pixel value corresponding to are read out.

  In step S1210, the relative difference value D is calculated from the above equation (1) based on the Gr average pixel value and the Gb average pixel value.

  In step S1220, a correction coefficient α for correcting the Gr pixel and the Gb pixel is calculated based on the relative difference value D calculated in step S1210.

  FIG. 13 is a diagram illustrating the relationship between the relative difference value D and the correction coefficient α. When the relative difference value D is less than the threshold value D11, the correction coefficient α is 0, which is the minimum value. When the relative difference value D is greater than or equal to the threshold value D12 (D11 <D12), the correction coefficient α is 1/8 of the maximum value. . When the relative difference value D is equal to or greater than the threshold value D11 and less than the threshold value D12, the correction coefficient α is between 0 and 1/8 as the relative difference value D increases as shown in FIG. The value becomes monotonically increasing.

  The level difference detection unit 1053A has table data that defines the relationship between the relative difference value D and the correction coefficient α as shown in FIG. 13 in the internal memory, and is based on the relative difference value D calculated in step S1210. The correction coefficient α is calculated by referring to the table data.

  In step S1230, the correction coefficient α calculated in step S1220 is stored in the correction coefficient map memory 1057.

  In step S1240, it is determined whether or not the processing from step S1210 to step S1230 has been performed on the entire area of the image data. If it is determined that the processing for all areas of the image data has not been completed, the process advances to step S1250.

  In step S1250, the Gr average pixel value and the Gb average pixel value corresponding to the next processing target area are read from the reduced image memory 1052, and the process proceeds to step S1210, where the processes from step 1210 to step S1230 are performed. As a result, the correction coefficient α is calculated for each region having a predetermined size, and the calculated correction coefficient α is stored in the correction coefficient map memory 1057.

  On the other hand, if it is determined in step S1240 that the processing for all the regions of the image data has been completed, the processing of the flowchart shown in FIG. In the following description, a plurality of correction coefficients α stored in the correction coefficient map memory 1057 are collectively referred to as a correction coefficient map.

  Returning to the flowchart shown in FIG. In step S1110, the step correction unit 1055A reads the Bayer image data from the SDRAM 108, and corrects the pixel values of the Gb pixel and the Gr pixel of the Bayer image data based on the correction coefficient map created in step S1100. Specifically, the pixel value of the corrected Gb pixel is obtained from the following equation (4), and the pixel value of the corrected Gr pixel is obtained from the following equation (5).

Gb after correction = Gb before correction × (1−4α) + (peripheral Gr1 + peripheral Gr2 ++ peripheral Gr3 + peripheral Gr4) × α (4)
After correction Gr = Gr before correction × (1−4α) + (peripheral Gb1 + peripheral Gb2 + peripheral Gb3 + peripheral Gb4) × α (5)
FIG. 14A is a diagram illustrating an example of an image in which a subject 140 having very fine edges and ghost light 141 exist. FIG. 14A also shows regions 142 and 143 having a predetermined size. FIG. 14B is a diagram showing a correction coefficient map 145 created based on the image shown in FIG. In FIG. 14B, in order to facilitate the description, the correction coefficient α is expressed as black as the correction coefficient α approaches 0 of the minimum value, and white as the correction coefficient α approaches 1/8 of the maximum value. Yes.

  As can be seen from FIGS. 14A and 14B, the correction coefficient α in the region where the ghost light 141 exists on the image is 1/8, which is the maximum value, or a value close to 1/8. Yes. Further, it can be seen that the correction coefficient of the region 140 where the fine edge exists is 0 or a value close to 0 which is the minimum value.

  As described above, in the second embodiment, the correction coefficient α is determined for each region of the image based on the Gr average pixel value and the Gb average pixel value, and the Gr pixel and the Gb pixel are corrected. Thereby, the correction for suppressing the signal difference can be performed on the Gr pixel and the Gb pixel in the region where the ghost light exists in the image data. Accordingly, as shown in FIG. 14A, the sharpness of the fine edges is not lost even when there is a subject having fine edges together with the ghost light.

  As described above, according to the imaging device in the second embodiment, the image data obtained from the output of the solid-state imaging element is Gr, which is the average value of the pixel values of the Gr pixels for each image region composed of a predetermined number of pixels. The average pixel value is calculated, the Gb average pixel value, which is the average value of the Gb pixel values, is calculated, and the Gr pixel value and the Gr pixel value are determined for each image area based on the calculated Gr average pixel value and Gb average pixel value A correction amount for correcting the pixel value of the Gb pixel is calculated. Then, since the pixel values of the Gr pixel and the Gb pixel are corrected for each image region based on the calculated correction amount, the correction for suppressing the signal difference between the Gr pixel and the Gb pixel may be performed for each image region. it can. Accordingly, correction for suppressing the signal difference can be effectively performed for the area where the ghost light exists, and the signal difference is suppressed for the subject area having a fine edge. Therefore, it is possible to prevent the sharpness of the edge from being lost.

  Further, a difference value between the Gr average pixel value and the Gb average pixel value is calculated for each image region, and when the calculated difference value is smaller than the first predetermined value D11, the correction amount is set to 0, and the difference value is the first value. When the second predetermined value D12 is greater than or equal to the second predetermined value D11, the correction amount is the maximum correction amount, and the difference value is equal to or greater than the first predetermined value D11 and smaller than the second predetermined value D12. As the difference value increases, the correction amount is increased monotonically between 0 and the maximum correction amount. Thereby, the correction for suppressing the signal difference can be effectively performed according to the magnitude of the signal difference between the Gr pixel and the Gb pixel.

  In particular, in the imaging device according to the second embodiment, when the correction amount is a correction coefficient and the processing target pixel is a Gr pixel, the pixel value of the Gr pixel and the pixel of the Gb pixel located around the Gr pixel The weighted average addition is performed using the correction coefficient, and when the pixel to be processed is the Gb pixel, the pixel value of the Gb pixel and the pixel value of the Gr pixel located around the Gb pixel are weighted average using the correction coefficient. By adding, the pixel values of the Gr pixel and the Gb pixel are corrected. Thereby, it is possible to effectively perform correction for suppressing the signal difference according to the magnitude of the signal difference between the Gr pixel and the Gb pixel while suppressing a decrease in the sharpness of the image.

  In the description of the first and second embodiments described above, the processing performed by the image processing unit 105 is based on hardware processing, but is not limited to such a configuration. For example, a configuration in which processing is performed separately by software is also possible. In this case, the image processing unit (image processing apparatus) includes a main storage device such as a CPU and a RAM, and a computer-readable storage medium storing a program for realizing all or part of the above processing. Here, this program is called an image processing program. Then, the CPU reads out the image processing program stored in the storage medium and executes information processing / calculation processing, thereby realizing processing similar to that of the image processing unit 105 described above.

  Here, the computer-readable recording medium refers to a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, and the like. Alternatively, the image processing program may be distributed to a computer via a communication line, and the computer that has received the distribution may execute the image processing program.

  The present invention is not limited to the first and second embodiments described above, and various modifications and applications are possible without departing from the spirit of the present invention. For example, the relative difference value D shown in Expression (1) is calculated as the difference value between the Gr average pixel value and the Gb average pixel value, but the present invention is not limited to this.

  Further, the method for correcting the pixel value of the Gr pixel and the pixel value of the Gb pixel is not limited to the methods shown in the equations (2) and (3), or the equations (4) and (5). .

102 ... Image sensor 105, 105A ... Image processor 108 ... SDRAM
1051... LPF unit 1052. Reduced image memory 1053 and 1053 A. Step detection unit 1054. Control unit 1055 and 1055 A. Step correction unit 1056.

Claims (10)

A solid-state imaging device having a Bayer array structure in which lines in which R pixels and Gr pixels are alternately arranged in the horizontal direction and lines in which B pixels and Gb pixels are alternately arranged in the horizontal direction are alternately arranged in the vertical direction. An imaging device comprising:
For the image data obtained from the output of the solid-state imaging device, for each image region composed of a predetermined number of pixels, a Gr average pixel value that is an average value of the pixel values of the Gr pixels included in the image region is obtained. An average pixel value calculation unit for obtaining a Gb average pixel value that is an average value of pixel values of Gb pixels included in the image region;
A correction determination unit that determines whether to correct the pixel value of the Gr pixel and the pixel value of the Gb pixel based on the Gr average pixel value and the Gb average pixel value;
A correction unit that corrects the pixel value of the Gr pixel and the pixel value of the Gb pixel when the correction determination unit determines that the correction is performed;
Equipped with a,
The correction determination unit calculates a difference value between the Gr average pixel value and the Gb average pixel value for each of the image regions. If the calculated difference value is equal to or greater than a first threshold, the difference value is cumulatively added. And determining that correction of the pixel value of the Gr pixel and the pixel value of the Gb pixel is performed when a value obtained by cumulatively adding the difference values is equal to or greater than a second threshold value that is greater than the first threshold value.
An imaging apparatus characterized by that. The difference value is a relative difference value obtained by dividing the difference value between the Gr average pixel value and the Gb average pixel value by the average value of the Gr average pixel value and the Gb average pixel value.
The imaging apparatus according to claim 1 . A solid-state imaging device having a Bayer array structure in which lines in which R pixels and Gr pixels are alternately arranged in the horizontal direction and lines in which B pixels and Gb pixels are alternately arranged in the horizontal direction are alternately arranged in the vertical direction. An imaging device comprising:
For the image data obtained from the output of the solid-state imaging device, for each image region composed of a predetermined number of pixels, a Gr average pixel value that is an average value of the pixel values of the Gr pixels included in the image region is obtained. An average pixel value calculation unit for obtaining a Gb average pixel value that is an average value of pixel values of Gb pixels included in the image region;
A correction determination unit that determines whether to correct the pixel value of the Gr pixel and the pixel value of the Gb pixel based on the Gr average pixel value and the Gb average pixel value;
A correction unit that corrects the pixel value of the Gr pixel and the pixel value of the Gb pixel when the correction determination unit determines that the correction is performed;
Equipped with a,
The correction unit corrects the pixel value of the Gr pixel that is the processing target pixel based on the pixel value of the Gb pixel that is located around the Gr pixel that is the processing target pixel, and the Gb pixel that is the processing target pixel. Correcting the pixel value of the Gb pixel that is the processing target pixel based on the pixel value of the Gr pixel located in the periphery;
An imaging apparatus characterized by that. A solid-state imaging device having a Bayer array structure in which lines in which R pixels and Gr pixels are alternately arranged in the horizontal direction and lines in which B pixels and Gb pixels are alternately arranged in the horizontal direction are alternately arranged in the vertical direction. An imaging device comprising:
For the image data obtained from the output of the solid-state imaging device, for each image region composed of a predetermined number of pixels, a Gr average pixel value that is an average value of the pixel values of the Gr pixels included in the image region is obtained. An average pixel value calculation unit for obtaining a Gb average pixel value that is an average value of pixel values of Gb pixels included in the image region;
A correction amount calculation unit that calculates a correction amount for correcting the pixel value of the Gr pixel and the pixel value of the Gb pixel based on the Gr average pixel value and the Gb average pixel value for each image region;
A correction unit that corrects the pixel values of the Gr pixel and the Gb pixel in the image region based on the correction amount calculated by the correction amount calculation unit for each image region;
Equipped with a,
The correction amount calculation unit calculates a difference value between the Gr average pixel value and the Gb average pixel value for each of the image regions, and when the calculated difference value is smaller than a first predetermined value, the correction amount is set to 0. And when the difference value is equal to or greater than a second predetermined value greater than the first predetermined value, a correction amount is set as a maximum correction amount, the difference value is equal to or greater than the first predetermined value, and If the difference value is smaller than the second predetermined value, the correction amount is increased monotonically between 0 and the maximum correction amount as the difference value increases.
An imaging apparatus characterized by that. The difference value is a relative difference value obtained by dividing the difference value between the Gr average pixel value and the Gb average pixel value by the average value of the Gr average pixel value and the Gb average pixel value.
The imaging apparatus according to claim 4 . A solid-state imaging device having a Bayer array structure in which lines in which R pixels and Gr pixels are alternately arranged in the horizontal direction and lines in which B pixels and Gb pixels are alternately arranged in the horizontal direction are alternately arranged in the vertical direction. An imaging device comprising:
For the image data obtained from the output of the solid-state imaging device, for each image region composed of a predetermined number of pixels, a Gr average pixel value that is an average value of the pixel values of the Gr pixels included in the image region is obtained. An average pixel value calculation unit for obtaining a Gb average pixel value that is an average value of pixel values of Gb pixels included in the image region;
A correction amount calculation unit that calculates a correction amount for correcting the pixel value of the Gr pixel and the pixel value of the Gb pixel based on the Gr average pixel value and the Gb average pixel value for each image region;
A correction unit that corrects the pixel values of the Gr pixel and the Gb pixel in the image region based on the correction amount calculated by the correction amount calculation unit for each image region;
Equipped with a,
The correction amount calculated by the correction amount calculation unit is a correction coefficient,
When the processing target pixel is a Gr pixel, the correction unit performs a weighted average addition of the pixel value of the Gr pixel and the pixel value of a Gb pixel located around the Gr pixel based on the correction coefficient, and performs processing When the target pixel is a Gb pixel, the Gr pixel and the Gb pixel are obtained by performing a weighted average addition based on the correction coefficient of the pixel value of the Gb pixel and the pixel value of the Gr pixel located around the Gb pixel. Correct the pixel value of
An imaging apparatus characterized by that. A solid-state imaging device having a Bayer array structure in which lines in which R pixels and Gr pixels are alternately arranged in the horizontal direction and lines in which B pixels and Gb pixels are alternately arranged in the horizontal direction are alternately arranged in the vertical direction. An imaging method using an imaging apparatus having
For the image data obtained from the output of the solid-state imaging device, for each image region composed of a predetermined number of pixels, a Gr average pixel value that is an average value of the pixel values of the Gr pixels included in the image region is obtained. Obtaining a Gb average pixel value which is an average value of pixel values of Gb pixels included in the image region;
Determining whether to correct the pixel value of the Gr pixel and the pixel value of the Gb pixel based on the Gr average pixel value and the Gb average pixel value;
Determining that the correction is to be performed, correcting the pixel value of the Gr pixel and the pixel value of the Gb pixel;
Equipped with a,
In the step of determining whether or not to perform the correction, a difference value between the Gr average pixel value and the Gb average pixel value is calculated for each image region, and if the calculated difference value is equal to or greater than a first threshold value. When the difference value is cumulatively added, and the value obtained by cumulatively adding the difference values is equal to or greater than a second threshold value that is greater than the first threshold value, the pixel value of the Gr pixel and the pixel value of the Gb pixel are corrected. To determine
An imaging method characterized by the above.   A solid-state imaging device having a Bayer array structure in which lines in which R pixels and Gr pixels are alternately arranged in the horizontal direction and lines in which B pixels and Gb pixels are alternately arranged in the horizontal direction are alternately arranged in the vertical direction. An imaging method using an imaging apparatus having
  For the image data obtained from the output of the solid-state imaging device, for each image region composed of a predetermined number of pixels, obtain a Gr average pixel value that is an average value of the pixel values of the Gr pixels included in the image region Obtaining a Gb average pixel value which is an average value of pixel values of Gb pixels included in the image region;
  Determining whether to correct the pixel value of the Gr pixel and the pixel value of the Gb pixel based on the Gr average pixel value and the Gb average pixel value;
  Determining that the correction is to be performed, correcting the pixel value of the Gr pixel and the pixel value of the Gb pixel;
With
  In the correcting step, the pixel value of the Gr pixel that is the processing target pixel is corrected based on the pixel value of the Gb pixel that is located around the Gr pixel that is the processing target pixel, and the Gb pixel that is the processing target pixel Correcting the pixel value of the Gb pixel as the processing target pixel based on the pixel value of the Gr pixel located in the vicinity of
An imaging method characterized by the above. A solid-state imaging device having a Bayer array structure in which lines in which R pixels and Gr pixels are alternately arranged in the horizontal direction and lines in which B pixels and Gb pixels are alternately arranged in the horizontal direction are alternately arranged in the vertical direction. An imaging method using an imaging apparatus having
For the image data obtained from the output of the solid-state imaging device, for each image region composed of a predetermined number of pixels, a Gr average pixel value that is an average value of the pixel values of the Gr pixels included in the image region is obtained. Obtaining a Gb average pixel value which is an average value of pixel values of Gb pixels included in the image region;
Calculating a correction amount for correcting the pixel value of the Gr pixel and the pixel value of the Gb pixel based on the Gr average pixel value and the Gb average pixel value for each image region;
Correcting the pixel values of Gr pixels and Gb pixels in the image region based on the correction amount for each image region;
Equipped with a,
In the step of calculating the correction amount, a difference value between the Gr average pixel value and the Gb average pixel value is calculated for each of the image regions, and when the calculated difference value is smaller than a first predetermined value, the correction amount Is set to 0, and when the difference value is equal to or larger than a second predetermined value larger than the first predetermined value, a correction amount is set as a maximum correction amount, the difference value is equal to or larger than the first predetermined value, and If the difference value is smaller than the second predetermined value, the correction amount is increased monotonically between 0 and the maximum correction amount as the difference value increases.
An imaging method characterized by the above. A solid-state imaging device having a Bayer array structure in which lines in which R pixels and Gr pixels are alternately arranged in the horizontal direction and lines in which B pixels and Gb pixels are alternately arranged in the horizontal direction are alternately arranged in the vertical direction. An imaging method using an imaging apparatus having
For the image data obtained from the output of the solid-state imaging device, for each image region composed of a predetermined number of pixels, a Gr average pixel value that is an average value of the pixel values of the Gr pixels included in the image region is obtained. Obtaining a Gb average pixel value which is an average value of pixel values of Gb pixels included in the image region;
Calculating a correction amount for correcting the pixel value of the Gr pixel and the pixel value of the Gb pixel based on the Gr average pixel value and the Gb average pixel value for each image region;
Correcting the pixel values of Gr pixels and Gb pixels in the image region based on the correction amount for each image region;
With
The correction amount is a correction coefficient,
In the correcting step, when the processing target pixel is a Gr pixel, the pixel value of the Gr pixel and the pixel value of the Gb pixel located around the Gr pixel are weighted and averaged based on the correction coefficient, When the pixel to be processed is a Gb pixel, the Gr pixel and the Gb pixel are obtained by performing a weighted average addition on the basis of the correction coefficient of the pixel value of the Gb pixel and the pixel value of the Gr pixel located around the Gb pixel. Correct the pixel value of the pixel,
An imaging method characterized by the above.