JP2008177794A - Color shading correcting apparatus of imaging apparatus, imaging apparatus, and color shading correcting method of imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately correct color shading characteristics even when shading characteristics are asymmetrical vertically and horizontally with respect to an optical axis and when the shading characteristics are different for each color filter due to dispersion in a manufacture process. <P>SOLUTION: The color shading correction apparatus includes a standard shading information storage part 411a' for storing standard shading information that the imaging apparatus has and an intrinsic shading information storage part 411a for storing the shading information of respective colors that each imaging apparatus has, and color shading correction coefficients for respective colors can be calculated by a color shading correction coefficient preparation part 411b on the basis of each shading information. When performing photographing, the color shading correction of picked-up images is performed by a color shading correction part 412 on the basis of the calculated color shading correction coefficients. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention provides color shading correction for image data captured by an imaging apparatus such as a digital camera using a solid-state imaging device such as a CCD image sensor or a CMOS image sensor, or a camera for a portable electronic information device. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color shading correction apparatus for an image pickup apparatus, an image pickup apparatus provided with the shading correction apparatus, and a color shading correction method for the image pickup apparatus.

  2. Description of the Related Art Conventionally, along with miniaturization of mobile phones, miniaturization and low profile of camera modules mounted thereon have been progressing. In order to reduce the height of the camera module, the lens (optical system) and image sensor (solid-state image sensor) of the camera module are arranged close to each other so that a phenomenon called color shading is noticeable. It has become to.

  In order to improve this color shading problem, for example, in the conventional imaging device disclosed in Patent Document 1, color shading correction is performed based on a shading correction coefficient corresponding to each color of the color filter. This will be described with reference to FIGS. 15 and 16A to 16C.

  As shown in FIG. 15, first, in step S101, the exit pupil position of the lens is detected. Next, in step S102, the shading correction coefficient is calculated so as to change in a pseudo-concentric manner common to RGB as shown in FIG. 16B, with the exit pupil position of the lens detected in step S101 as the center. Thereafter, in step S103, the RGB common shading correction coefficient calculated in step S102, which is changed in a pseudo-concentric manner, is multiplied by the correction luminance data (RGB shading characteristics shown in FIG. 16A) of each pixel. Shading correction calculation is performed. Thus, shading correction is performed as shown in FIG.

For example, in the conventional imaging device disclosed in Patent Document 2, a white reference or black reference object is imaged to acquire white reference data or black reference data of all pixel regions, and the reference data is used as the reference data. A shading correction value to be corrected so as to be substantially the same level over the entire pixel region is calculated, and the image data is corrected based on the shading correction value.
JP 2002-218298 A JP 2000-13807 A

  However, the above prior art has the following problems.

  In the conventional imaging device disclosed in Patent Document 1, a shading correction coefficient common to RGB is calculated based on exit pupil position information and the zoom position, focus position, image height, aperture amount, and the like of the imaging lens. Since the shading correction coefficients are concentric, the shading characteristics are asymmetrical with respect to the optical axis, and when the shading characteristics are different for each sensor (each color filter) due to variations in the manufacturing process. It was difficult to deal with. In addition, as shown in FIG. 16C, shading correction may not be possible depending on the color.

  Further, in the conventional imaging device disclosed in Patent Document 2, although the shading correction is performed so that the image data of the white reference or the black reference becomes substantially the same level over all pixels, In some cases, the shading correction coefficient is not calculated for each imaging device from the captured image data of the subject with uniform brightness, and shading correction may not be possible depending on the imaging device.

  The present invention solves the above-mentioned conventional problems, and even when the shading characteristics are asymmetrical with respect to the optical axis, and when the shading characteristics differ for each color filter due to variations in the manufacturing process, the color shading characteristics It is an object of the present invention to provide a color shading correction device for an image pickup apparatus that can correct the image more accurately, an image pickup apparatus including the color shading correction device, and a color shading correction method for the image pickup apparatus.

  The color shading correction apparatus for an image pickup apparatus according to the present invention includes a unique shading information storage unit that captures a subject with uniform color and brightness using the image pickup apparatus, and stores unique shading information for each color for each image pickup apparatus; Color shading correction coefficient creating means for creating a unique color shading correction coefficient for each imaging device based on color shading characteristics obtained from unique shading information for each color, and color shading for captured image data using the color shading correction coefficient Color shading correction means for performing correction, whereby the above object is achieved.

  Preferably, the unique shading information storage means in the color shading correction apparatus of the imaging apparatus of the present invention stores unique shading information of each pixel of two or more colors that the imaging apparatus has.

  Further preferably, the unique shading information storage means in the color shading correction device of the imaging device of the present invention is the pixel data when the subject having uniform color and brightness is photographed as the unique shading information of each of the imaging devices. And the difference between the pixel data of the standard shading characteristic data corresponding to the pixel data is stored.

  Furthermore, it is preferable that the unique shading information storage means in the color shading correction device of the imaging device of the present invention includes two or more pixel colors when the subject having the same color and brightness is photographed by the imaging device. A ratio between the signal and the color signal of the standard shading characteristic data corresponding to the color signal, or pixel data of each color of two or more colors is stored as the specific shading information.

  Furthermore, it is preferable that the color shading correction apparatus for an image pickup apparatus according to the present invention further includes standard shading information storage means for storing standard shading information for each color of the image pickup apparatus as the standard shading characteristic data.

  Further preferably, the color shading correction coefficient creating means in the color shading correction apparatus of the imaging apparatus according to the present invention calculates the color shading correction coefficient based on the standard shading information of each color and the unique shading information.

  Further preferably, the color shading correction coefficient creating means in the color shading correction device of the imaging device of the present invention is based on the standard shading information of each color and the inherent shading information, and the shading characteristics of each color of two or more colors. Each inverse function is calculated as a color shading correction coefficient.

  Furthermore, it is preferable that the unique shading information storage unit in the color shading correction device of the imaging device of the present invention is a point for each of two or more colors when the subject having a uniform color and brightness is photographed by the imaging device. Pixel data at symmetrical positions is stored as the inherent shading information.

  Further preferably, the unique shading information storage means in the color shading correction apparatus of the imaging apparatus of the present invention is a diagonal line for each of two or more colors when the subject having the same color and brightness is photographed by the imaging apparatus. Pixel data at the upper position is stored as the inherent shading information.

  Further preferably, the unique shading information storage means in the color shading correction device of the imaging device of the present invention is the same for each of two or more colors when the imaging device captures a subject with uniform color and brightness. Pixel data at a position on the horizontal axis and / or a position on the same vertical axis is stored as the inherent shading information.

  Furthermore, preferably, the unique shading information storage means in the color shading correction apparatus of the imaging apparatus according to the present invention stores the optical center position of the color shading characteristic obtained from the color signal of the captured image.

  Further, preferably, the inherent shading information storage means in the color shading correction apparatus of the imaging apparatus of the present invention stores an optical center level of color shading characteristics obtained from a color signal of the captured image.

  Further, preferably, the inherent shading information storage means in the color shading correction apparatus of the imaging apparatus according to the present invention stores the slope of the color shading characteristic obtained from the color signal of the captured image.

  Further, preferably, the intrinsic shading information storage means in the color shading correction apparatus of the imaging apparatus of the present invention stores a luminance level of two or more pixels of the captured image.

  Further, preferably, the inherent shading information storage means in the color shading correction apparatus of the imaging apparatus of the present invention stores a ratio of luminance levels of two or more pixels of the captured image.

  Further, preferably, the unique shading information storage means in the color shading correction apparatus of the image pickup apparatus of the present invention stores the optical center position of the color shading characteristic obtained from the luminance level of the picked-up image.

  Further, preferably, the inherent shading information storage means in the color shading correction apparatus of the imaging apparatus of the present invention stores the optical center level of the color shading characteristics obtained from the luminance level of the captured image.

  Further, preferably, the inherent shading information storage means in the color shading correction apparatus of the imaging apparatus according to the present invention stores the slope of the color shading characteristic obtained from the brightness level of the captured image.

  Further preferably, the color shading correction coefficient creating means in the color shading correction device of the imaging device of the present invention calculates the optical center position and the optical center level of the color shading characteristics approximated based on the inherent shading information, and The difference between the optical center position and the optical center level of the color shading characteristics approximated based on the standard shading information is calculated, and the shift and gain adjustment are performed based on the calculated information and the standard shading information. A corrected color shading characteristic is calculated, and an inverse function of the corrected color shading characteristic is calculated as a color shading correction coefficient.

  Furthermore, it is preferable that the unique shading information storage unit in the color shading correction apparatus of the imaging apparatus of the present invention is an arbitrary for each of two or more colors when the subject having the same color and brightness is captured by the imaging apparatus. Each pixel data of the position is stored as the unique shading information.

  Further preferably, the unique shading information storage means in the color shading correction apparatus of the imaging apparatus according to the present invention is a grid for each of two or more colors when the subject having a uniform color and brightness is photographed by the imaging apparatus. Each pixel data of the shape position is stored as the unique shading information.

  Further preferably, in the color shading correction apparatus for an image pickup apparatus according to the present invention, pixel data not stored is linearly determined based on two or more adjacent pixel data stored in the inherent shading information storage means. There is further provided a shading information interpolation means for obtaining color shading characteristics by interpolation or non-linear interpolation.

  Further preferably, the color shading correction coefficient creating means in the color shading correction apparatus of the imaging apparatus according to the present invention calculates an inverse function of the color shading characteristic as a color shading correction coefficient.

  Further preferably, the color shading correction coefficient creating means in the color shading correction apparatus of the imaging apparatus of the present invention is provided with a color shading correction coefficient storage means for storing the color shading correction coefficient.

  Further preferably, the color shading correction means in the color shading correction apparatus of the imaging apparatus of the present invention performs color shading correction by multiplying the input image data to be corrected by the color shading correction coefficient.

  Still preferably, in a color shading correction apparatus for an imaging apparatus according to the present invention, the two or more colors include at least two primary colors of R (red), G (green), and B (blue).

  Still preferably, in a color shading correction apparatus for an image pickup apparatus according to the present invention, the approximated color shading characteristic is a quadratic function.

  Further preferably, in the color shading correction device of the imaging device of the present invention, when the color signal of the two or more pixels is a first color signal and the color signal of the standard shading characteristic data is a second color signal, The ratio is the second color signal / the first color signal.

  Further preferably, the color shading correction coefficient creating means in the color shading correction device of the image pickup apparatus of the present invention is characterized in that the color shading as an inverse function of a color shading characteristic obtained by adding standard shading information of each color to the inherent shading information. A correction coefficient is calculated.

  Further preferably, the color shading correction coefficient creating means in the color shading correction apparatus of the image pickup apparatus of the present invention calculates the color shading correction coefficient by dividing the inherent shading information by the standard shading information of each color.

  An image pickup apparatus of the present invention includes a solid-state image pickup device that photoelectrically converts light incident through an optical system for each pixel, and color shading correction of each image data that is photoelectrically converted by the solid-state image pickup device. The color shading correction apparatus according to the present invention that performs the above-described purpose is achieved, thereby achieving the above object.

  Preferably, the solid-state imaging device in the imaging apparatus of the present invention is a CCD image sensor or a CMOS image sensor.

  The color shading correction method for an image pickup apparatus according to the present invention includes a standard shading information storage step for storing standard shading information of an image pickup apparatus in a standard shading information storage unit, and each pixel of two or more colors of each image pickup apparatus. A unique shading information storage step for storing the unique shading information in the unique shading information storage means, and the shading characteristics of two or more colors based on the shading information stored in the standard shading information storage means and the unique shading information storage means. A color shading correction coefficient creating step for calculating each inverse function as a color shading correction coefficient, and a color shading correction step for performing color shading correction based on the calculated color shading correction coefficient. Ri, the object is achieved.

  The color shading correction method for an image pickup apparatus according to the present invention includes a standard shading information storage step for storing standard shading information of an image pickup apparatus in a standard shading information storage unit, and each pixel of two or more colors of each image pickup apparatus. A unique shading information storage step for storing the unique shading information in the unique shading information storage means; and an optical center position and an optical center level of a color shading characteristic approximated based on the unique shading information; The difference between the optical center position and the optical center level of the color shading characteristics approximated based on the shading information is calculated, and the color corrected by shift and gain adjustment based on the calculated information and the standard shading information Shading characteristics A color shading correction coefficient creating step for calculating an inverse function of the corrected color shading characteristics as a color shading correction coefficient, and a color shading correction step for performing color shading correction based on the calculated color shading correction coefficient Therefore, the above object can be achieved.

  According to the color shading correction method of the image pickup apparatus of the present invention, the unique shading information storage step of storing the unique shading information of each pixel of two or more colors of each image pickup apparatus in the unique shading information storage means, and the unique shading information storage means A shading information interpolation step for calculating color shading characteristics by interpolating other unstored unique shading information using the unique shading information stored in the above, and an inverse function of the color shading characteristics including the interpolated unique shading information A color shading correction coefficient creating step for calculating the color shading correction coefficient, and a color shading correction step for performing color shading correction based on the calculated color shading correction coefficient. Target is achieved.

  Preferably, in the color shading correction method for an image pickup apparatus according to the present invention, a solid-state image sensor that photoelectrically converts light incident through the optical system for each pixel, and an image that is photoelectrically converted by the solid-state image sensor. When manufacturing an imaging device including a color shading correction device that performs color shading correction of each image data that has been obtained, the unique shading information is photographed for each of the imaging devices with each color and brightness being uniform. And get.

  The operation of the present invention will be described below with the above configuration.

  The color shading correction apparatus of the imaging apparatus according to the present invention captures a subject with uniform color and brightness by the imaging apparatus, and obtains a unique color shading correction coefficient for each imaging apparatus from the unique shading information of each color. Since shading correction is performed, color shading characteristics can be corrected more accurately even when the shading characteristics are asymmetrical with respect to the optical axis, and when the shading characteristics differ for each color filter due to variations in the manufacturing process. It becomes possible.

  Specifically, for example, in order to correct color shading of each color in a captured image, standard shading information storage means for storing standard shading information included in the imaging device, and pixels of at least two colors included in each imaging device Specific shading information storage means for storing the specific shading information. The intrinsic shading information storage means stores the luminance levels (RGB color data) of at least two pixels when a subject having a uniform color and brightness is photographed by the imaging device when the imaging device is manufactured. Difference information from the standard shading data is stored as unique shading information. Based on the shading information stored in the standard shading information storage means and the unique shading information storage means, the color shading correction coefficient for each color is calculated by the color shading correction coefficient creating means. At the time of shooting, the color shading correction of the captured image is performed by the color shading correction means based on the calculated color shading correction coefficient for each color.

  In addition, in order to correct the color shading of each color in the captured image, a unique shading information storage unit that stores unique shading information of at least two colors of pixels included in each imaging device is provided. The intrinsic shading information storage means stores, as intrinsic shading information, the luminance levels of pixels of at least two colors when a subject of uniform color and brightness is photographed by the imaging device when the imaging device is manufactured. The unique shading information for each color stored in the unique shading information storage means is interpolated by the shading information interpolation means for non-stored image data to calculate color shading characteristics. Based on the calculated color shading characteristics, a color shading correction coefficient for each color is calculated by the color shading correction coefficient creating means. At the time of shooting, the color shading correction of the captured image is performed by the color shading correction unit based on the calculated color shading correction coefficient.

  As described above, according to the present invention, a subject having a uniform color and brightness is photographed by the imaging device, and a color shading correction is performed by obtaining a unique color shading correction coefficient for each imaging device from the unique shading information of each color. Therefore, when the relative position of the optical lens and the imaging element is shifted in the manufacturing process of the imaging device, or when the color shading characteristics are asymmetrical or complex around the optical axis, each color filter varies depending on the manufacturing process. Even when the color shading characteristics are different, the color shading characteristics can be corrected more accurately.

  Embodiments 1 to 3 of the color shading correction apparatus for an image pickup apparatus according to the present invention will be described below with reference to a primary color CCD area sensor (CCD) having red (R), green (G) and blue (B) color filters as solid-state image sensors. A case where the present invention is applied to a single-plate type digital camera equipped with a type image sensor will be described in detail with reference to the drawings. Before that, an example of the basic configuration of the color shading correction apparatus of the imaging apparatus of the present invention will be described.

  FIG. 1 is a block diagram illustrating a basic configuration example of a color shading correction apparatus for an image pickup apparatus according to the present invention.

  In FIG. 1, a color shading correction device 41 of an imaging apparatus according to the present invention photographs a subject (such as R / G / B / white / gray) having a uniform color and brightness with a imaging device in a predetermined manufacturing process. A unique color shading information storage unit 411a serving as a unique shading information storage unit that stores unique shading information of each color for each imaging device, and a unique shading characteristic obtained from the unique shading information of each RGB color (a graph in which each data is connected) ) As a color shading correction coefficient, and a color shading correction coefficient creating unit 411b as a color shading correction coefficient creating means, and the RGB shading correction coefficients for each input color signal (captured image data) to be corrected. A shading correction means for performing color shading correction by multiplication; And a color shading correction unit 412 of the Te.

  The operation of the above configuration will be described.

  FIG. 2 is a flowchart for explaining each processing procedure of the color shading correction method using the color shading correction apparatus 41 of FIG.

  As shown in FIG. 2, first, in step S1, a subject having a uniform color and brightness is photographed for each image pickup device in the manufacturing process, and the unique color shading information storage unit stores the unique shading information of each color for each image pickup device. It memorize | stores in 411a.

  Next, in step S2, the color shading correction coefficient creation unit 411b creates an inverse function of the inherent shading characteristics obtained from the inherent shading information of each RGB color as a color shading correction coefficient.

  Furthermore, in step S3, the color shading characteristics of the input RGB color signal (captured image data of each RGB color) to be corrected shown in FIG. Color shading correction is performed by multiplication by the shading correction unit 412 to obtain a stable color shading characteristic correction result as shown in FIG.

  Therefore, color shading correction is performed using the unique shading information of each color for each image pickup device. Therefore, when the color shading characteristics are asymmetrical with respect to the optical axis, the shading is performed for each color filter due to manufacturing process variations. Even when the characteristics are different, the color shading characteristics can be corrected more reliably.

Note that the color shading correction apparatus according to the first to third embodiments of the imaging apparatus according to the present invention is different due to the difference in configuration until the color shading correction coefficient is generated, such as the unique shading information storage unit 411a and the color shading correction coefficient generation unit 411b. Can be configured respectively.
(Embodiment 1)
In the first embodiment, as the unique shading information of each color of each image capturing apparatus, the difference between the RGB data of all effective pixel portions when a subject having a uniform color and brightness is photographed and the standard shading characteristic data serving as a reference. A case of storing the above will be described.

  FIG. 4 is a block diagram illustrating a configuration example of a main part of the digital camera according to Embodiment 1 of the present invention.

  In FIG. 4, the digital camera 10 </ b> A according to the first embodiment is an optical lens 1 as an optical system for condensing subject light, and a solid-state imaging device that photoelectrically converts light incident through the optical lens 1. The CCD (CCD type image sensor) 2 and the electric signal (imaging signal) from the CCD 2 are signal-processed, and the CCD signal processing unit / drive processing unit 3 that drives and controls imaging by the CCD 2 and the color shading correction processing, etc. And an image processing apparatus 4A for performing the processing.

  The CCD 2 includes an RGB color filter 22, a condensing microlens 23, and an IR (infrared) cut filter 24 on the imaging region of the solid-state imaging device 21 constituting a plurality of pixel units (light receiving units). They are provided in this order.

  The CCD signal processing unit / drive processing unit 3 performs predetermined digital conversion processing after the electrical signal (imaging signal) from the CCD 2 is correlated and sampled to reduce noise, and R (red), G ( Green (color) and B (blue) color signals (input RGB color signals) are generated.

  The image processing device 4A includes a color shading correction device 41A that performs color shading correction of a captured image captured by the CCD 2, an image processing unit 42, and a video signal output unit 43.

  The shading correction device 41A includes a color shading correction control unit 411A for controlling color shading correction, and a color shading correction unit 412 that performs color shading correction under the control of the color shading correction control unit 411A.

  The color shading correction control unit 411A controls information related to color shading correction, and includes a unique shading information storage unit 411aA for each color as a unique shading information storage unit, and standard shading information storage for each color as a standard shading information storage unit. And a color shading correction coefficient creating unit 411bA as a color shading correction coefficient creating means.

  In the unique shading information storage unit 411aA, shading information of pixels (pixel units) of two or more colors included in each imaging device is stored in advance in the manufacturing process in order to calculate color shading correction coefficients for each color of RGB. In the first embodiment, the intrinsic shading information storage unit 411aA captures imaging pixel data (RGB color data) of all effective pixel units and standard shading information when an imaging device captures a subject having a uniform color and brightness. The difference from the standard shading characteristic data (standard shading information; each image data constituting the standard shading characteristic) stored in the storage unit 411a ′ is stored in advance as inherent shading information when the imaging apparatus is manufactured.

  The standard shading information storage unit 411a 'stores in advance standard standard shading information included in the imaging apparatus as a reference value for calculating a color shading correction coefficient.

  The color shading correction coefficient creation unit 411bA calculates a color shading correction coefficient based on the shading information stored in the specific shading information storage unit 411aA and the standard shading information storage unit 411a ′, and calculates the calculated color shading correction coefficient. Is stored in a color shading correction coefficient storage unit (not shown) as color shading correction coefficient storage means. In the first embodiment, the color shading correction coefficient creation unit 411bA performs the standard shading information on the basis of the respective color shading information stored in the standard shading information storage unit 411a ′ and the unique shading information storage unit 411aA. In addition, an inverse function of the shading characteristics of each RGB color is calculated as a color shading correction coefficient, and this is stored as a shading correction coefficient for each RGB color in a predetermined color shading correction coefficient storage unit (not shown).

  The color shading correction unit 412 performs color shading correction on the captured image data for each RGB color based on the color shading correction coefficient for each RGB color calculated by the color shading correction coefficient creation unit 411bA. In the first embodiment, the color shading correction unit 412 calculates the color shading correction coefficient for each color of RGB calculated by the color shading correction coefficient generation unit 411bA, and the input RGB color signal input from the CCD signal processing unit / drive control unit 3. (Shaped image data) is multiplied to perform color shading correction.

  The image processing unit 42 performs predetermined digital signal processing on the image signal obtained from the color shading correction unit 412.

  The video signal output unit 43 converts the digital signal processed image signal from the image processing unit 42 into a predetermined video signal and outputs the signal.

  With the above configuration, first, in the CCD 2 of the digital camera 10A, the image light from the subject passes through the infrared cut filter 24, the micro lens 23, and the color filter 22 from the optical lens 1 and then is imaged by the solid-state imaging device 21. The light is condensed and imaged on a plurality of pixel portions (each light receiving portion) on the region. Each condensed image light is photoelectrically converted by each light receiving unit (photodiode unit) of the solid-state imaging device 21 to generate a signal charge for each pixel, and an electric signal (imaging signal) by this signal charge is generated. Charges are transferred to the CCD signal processor / drive processor 3.

  Next, the CCD signal processing unit / drive processing unit 3 performs correlated double sampling on the electrical signal from the CCD 2 to reduce noise, and then converts the digital signal to R (red), G (green), and B (blue). ) Each color signal is generated.

  On the other hand, based on the inherent shading information of each color stored in the standard shading information storage unit 411a ′ and the inherent shading information storage unit 411aA, the color shading correction coefficient generation unit 411bA generates an inverse function of the color shading characteristics of the RGB color signals. The shading correction coefficients calculated as shading correction coefficients are stored in a predetermined color shading correction coefficient storage unit (not shown).

  Each color signal (captured image data) from the CCD signal processing unit / drive processing unit 3 is converted into the color shading correction unit 412 (configured by a multiplier for each color) for each color calculated by the color shading correction coefficient generation unit 411bA. Each color shading correction coefficient is multiplied to perform color shading correction on the captured image data.

  Thereafter, each corrected color signal (captured image data) after color shading correction obtained from the color shading correction unit 412 is subjected to predetermined digital signal processing by the image processing unit 42 and predetermined by the video signal output unit 43. Converted to a video signal.

  Hereinafter, a color shading correction method in the digital camera 10A according to the first embodiment will be described in detail with reference to FIG.

  FIG. 5 is a flowchart for explaining each processing procedure of the color shading correction method in the digital camera 10A of FIG.

  First, in step S11, in a predetermined manufacturing process of the imaging device, a subject having a uniform color and brightness is photographed by each imaging device.

  In step S12, the RGB color data (captured image data) for all pixels and the standard shading characteristic data (standard data stored in the standard shading information storage unit 411a ′) from the captured image data of each color captured in step S11. The difference between the (shading information) and the image data is calculated, and this is recorded in the inherent shading information recording unit 411aA as inherent shading characteristic data (inherent shading information). This difference calculation may be performed by the color shading correction coefficient creation unit 411bA. In addition, FIG. 6A and FIG. 6B show the captured RGB color data (captured image data), standard shading information, and unique shading information obtained by calculating the difference between them.

  FIG. 6A shows an example of standard shading characteristic data (standard shading information) stored in the standard shading information storage unit 411a ′ and shading characteristic data of each RGB color obtained from the captured image data. FIG. 6B is a graph showing an example of inherent shading characteristic data (inherent shading information) that is difference-calculated and stored in the inherent shading information storage unit 411aA. In FIG. 6, the horizontal axis indicates each pixel position on the imaging region in the horizontal direction or the vertical direction.

  Next, in step S13, the color shading correction coefficient creation unit 411bA stores the unique shading information of each color stored in the unique shading information storage unit 411aA and the standard shading information of each color stored in the standard shading information storage unit 411a ′. Then, an inverse function of the shading characteristics of each of the RGB colors is calculated, and this is stored as a color shading correction coefficient in a predetermined color shading correction coefficient storage unit (not shown). FIG. 7A to FIG. 7C show the shading characteristic data of each RGB color, the color shading correction coefficient of the inverse function, and the RGB color data after the shading correction.

  FIG. 7A is a graph showing an example of shading characteristic data of each color of RGB, and FIG. 7B is a graph showing an example of a color shading correction coefficient which is an inverse function thereof, and FIG. These are graphs showing the result of correcting the color shading characteristics by multiplying the shading characteristic data shown in FIG. 7A by the color shading correction coefficient shown in FIG. In FIG. 7, the horizontal axis indicates the pixel position in the horizontal direction or the vertical direction, and the vertical axis indicates the level of the imaging signal of the pixel.

  In step S14, the color shading correction unit 412 sequentially multiplies the color shading correction coefficient of each RGB color to the captured pixel data (captured image data) of each RGB color from the CCD signal processing unit / drive processing unit 3. Then, color shading correction processing is sequentially performed. For example, by multiplying the RGB shading characteristic data shown in FIG. 7A by the color shading correction coefficient shown in FIG. 7B, the color shading characteristics shown in FIG. 7C are obtained. Can be corrected.

  As described above, the color shading correction method for the image pickup apparatus according to the first embodiment includes the standard shading information storage step of storing the standard shading information of the CCD 2 in the standard shading information storage unit 411a ′, and the individual CCD 2 has. Based on the unique shading information storage step of storing the unique shading information of the pixel portion of two or more colors in the unique shading information storage unit 411aA, and each shading information stored in the standard shading information storage unit 411a ′ and the unique shading information storage unit 411aA The color shading correction coefficient creation unit 411bA calculates a color shading correction coefficient creation step for calculating an inverse function of shading characteristics of two or more colors as a color shading correction coefficient, and a color shading compensation. The section 412, and a color shading correction step of performing color shading correction on the basis of the calculated color shading correction coefficient.

As described above, according to the digital camera 10A of the first embodiment, in the manufacturing process of the imaging device, the relative position between the optical lens 1 and the solid-state imaging device 21 (or / and the solid-state imaging device 21 and the condensing microlens 23). Even when the relative position is shifted, unique shading information of each color of RGB corresponding to each solid-state image pickup device 21 (each pixel unit) for each image pickup device is stored. Based on this, a color shading correction coefficient can be calculated. At the time of shooting, color shading correction is performed based on the color shading correction coefficient for each individual imaging device, so if the shading characteristics are asymmetric about the optical axis or complex for each color, variation in manufacturing process Even when there are individual differences among image capturing devices, such as when the shading characteristics differ from color filter to color filter, the color shading characteristics can be corrected more accurately. Absent.
(Embodiment 2)
The second embodiment is different from the calculation method of the color shading correction coefficient of the first embodiment, and among the captured images, the RGB color data of two or more pixels at point symmetry positions are used as specific shading information, A case will be described in which the intrinsic shading information is approximated to a quadratic function to derive the optical center position and its level.

  FIG. 8 is a flowchart for explaining each processing procedure of the color shading correction method in the digital camera according to the second embodiment of the present invention.

  As shown in FIG. 8, first, in step S21, a subject with uniform color and brightness is photographed by each imaging device in a predetermined manufacturing process of the imaging device.

  In step S22, among the captured images captured in step S21, RGB respective color data (pixel data of each color of two or more colors; here, RGB data of two or more colors) on a point-symmetrical position, for example, a diagonal line as shown in FIG. The pixel data of each color) is stored in the unique shading information storage unit 411aB as unique shading information.

  Next, in step S23, the inherent shading information stored in the inherent shading information storage unit 411aB is approximated to a quadratic function as shown in FIG. 10, and the optical center position and its level (optical center level) are derived.

  FIG. 10 is a graph illustrating an example of standard shading characteristics and shading characteristics predicted from measurement data in the digital camera 10B according to the second embodiment of the present invention, and the horizontal axis indicates the pixel position in the horizontal direction or the vertical direction, The vertical axis indicates the level of the imaging signal of the pixel.

  When the slope of the quadratic function indicating the standard shading characteristic is a, the optical center position of the standard shading characteristic is b, and the optical center level of the standard shading characteristic is c, the standard shading characteristic F (x) is expressed by the following equation (Equation 1 )like,

と表すことができる。

It can be expressed as.

Also, assuming that the optical center position predicted from the measurement data in the actual solid-state imaging device 21 is b ₀ and the optical center level of the predicted shading characteristic is c ₀ , the shading characteristic f (x) predicted from the measurement data is Like the following formula (Equation 2),

と表すことができる。

It can be expressed as.

Here, the optical center position b ₀ and the optical center level c ₀ are calculated by substituting the data of the two pixels stored in the inherent shading information storage unit 411aB as the approximate slope a = a ₀ of the quadratic function. The Differences b−b ₀ and c−c ₀ between the optical center position b and the optical center level c of the standard shading characteristics recorded in advance in the standard shading information storage unit 411a′B are calculated.

  Further, in step S24, the color shading correction coefficient creation unit 411bB performs shift and gain adjustment based on the calculated information and the standard shading information stored in the standard shading information storage unit 411a′B to perform correction. The shading characteristics of each of the RGB colors are calculated, an inverse function of the shading characteristics is calculated, and stored as a color shading correction coefficient in a predetermined color shading correction coefficient storage unit (not shown).

  Next, in step S25, color shading correction processing is performed by the color shading correction unit 412 by sequentially multiplying the color shading correction coefficient of each RGB color with respect to pixel data (captured image data) of each color of the captured image. .

  As described above, the color shading correction method for the imaging apparatus according to the second embodiment includes the standard shading information storage step for storing the standard shading information of the imaging apparatus in the standard shading information storage unit 411a′B, and individual imaging. A unique shading information storage step for storing the unique shading information of the pixel unit of two or more colors in the apparatus in the unique shading information storage unit 411aB, and a secondary approximated based on the unique shading information by the color shading correction coefficient creation unit 411bB Calculate the optical center position and optical center level of the function, and calculate the difference between these and the optical center position and optical center level of the quadratic function approximated based on the standard shading information. Shift based on standard shading information And a color shading correction coefficient creating step for calculating a color shading characteristic corrected by the gain adjustment and calculating an inverse function of the corrected color shading characteristic as a color shading correction coefficient, and a color shading correction unit 412 A color shading correction step for performing color shading correction based on the color shading correction coefficient.

As described above, also in the digital camera 10 </ b> B of the second embodiment, the relative position between the optical lens 1 and the solid-state imaging device 21 (or / and the solid-state imaging device 21 and the condensing microlens 23 in the manufacturing process of the imaging device). Even when the relative position is deviated, unique shading information for each color of RGB corresponding to each solid-state imaging device 21 (each pixel unit) for each imaging device is stored, and based on this unique shading information A color shading correction coefficient can be calculated. At the time of shooting, since color shading correction is performed based on the color shading correction coefficient for each individual imaging device, if the shading characteristics are asymmetric about the optical axis or complex for each color, further manufacture Color shading characteristics can be corrected more accurately even when there are individual differences among image pickup devices, such as when the shading characteristics differ for each color filter due to process variations. If you can't.
(Embodiment 3)
In the third embodiment, pixel data (captured image data) that is not stored is stored based on pixel data (captured image data) of two or more adjacent points stored in a specific shading information storage unit 411aC described later. A case where a shading information interpolation unit 411a ″ (to be described later) that obtains color shading characteristics by linear interpolation (or nonlinear interpolation) will be described in detail.

  FIG. 11 is a block diagram illustrating a configuration example of a main part of a digital camera according to Embodiment 3 of the present invention.

  In FIG. 11, the digital camera 10C according to the third embodiment has a color shading correction control unit 411C of the color shading correction device 41C instead of the color shading correction control unit 411A in the color shading correction device 41A of the first embodiment shown in FIG. Is provided.

  The color shading correction control unit 411C of the color shading correction device 41C is stored in the unique shading information storage unit 411aC that stores the unique shading information of at least two colors of pixels of each imaging device, and the unique shading information storage unit 411aC. The shading information interpolating unit 411a ″ as a shading information interpolating means for interpolating data not stored between these unique shading information (data) to obtain color shading characteristics, and this interpolated color shading The color shading correction coefficient creating unit 411bC calculates a color shading correction coefficient based on the characteristics.

  In the third embodiment, the intrinsic shading information storage unit 411aC stores pixel data at any position of at least two colors (here, three primary colors of RGB) when a subject having a uniform color and brightness is captured by the imaging device. (Captured image data) is stored as unique shading information.

  In the shading information interpolation unit 411a ″, pixel data (captured image data) that is not stored is stored based on two or more adjacent pixel data (captured image data) stored in the inherent shading information storage unit 411aC. The color shading correction coefficient creation unit 411bC calculates an inverse function of the interpolated color shading characteristic as a color shading correction coefficient.

  FIG. 12 is a flowchart for explaining each processing procedure of the color shading correction method in the digital camera 10C of FIG.

  As shown in FIG. 12, first, in step S31, a subject having a uniform color and brightness is photographed by each imaging device in a predetermined manufacturing process of the imaging device.

  Next, in step S32, among the captured images captured in step S31, for example, RGB color data for each pixel portion in a grid-like position at regular intervals as shown in FIG. It is stored in the information storage unit 411aC.

  In step S33, the shading information interpolation unit 411a "linearly interpolates pixel data not stored and based on the pixel data of two adjacent points stored in the unique shading information storage unit 411aC. .

  FIG. 14 is a diagram showing color shading characteristics predicted by linearly interpolating measurement data in the digital camera 10C of FIG. In FIG. 14, the horizontal axis indicates the pixel position in the horizontal direction or the vertical direction, and the vertical axis indicates the level of the imaging signal of the pixel portion.

  In step S34, the color shading correction coefficient creating unit 411bC calculates an inverse function of the color shading characteristic obtained from the inherent shading information including the interpolated pixel data as a color shading correction coefficient, and a color shading correction coefficient storage unit (not shown). I) Remember.

  In step S <b> 35, the color shading correction unit 412 performs color shading correction processing by sequentially multiplying the color shading correction coefficient of each RGB color by the pixel data of each color of the photographed image.

  As described above, the color shading correction method of the imaging device according to the third embodiment includes the unique shading information storage step of storing the unique shading information of the pixels of two or more colors included in each imaging device in the unique shading information storage unit 411aC. , The shading information interpolation unit 411a "interpolates the unique shading information of other pixels not stored in the unique shading information stored in the unique shading information storage unit 411aC to obtain color shading characteristics. A shading information interpolation step for calculating, and a color shading correction coefficient for calculating an inverse function of color shading characteristics obtained from the interpolated unique shading information as a color shading correction coefficient by the color shading correction coefficient generation unit 411bC. And forming step, the color shading correction unit 412, and a color shading correction step of performing color shading correction on the basis of the calculated color shading correction coefficient.

  As described above, also in the digital camera 10C of the third embodiment, in the manufacturing process of the imaging device, the relative position between the optical lens 1 and the solid-state imaging device 21 (or / and the solid-state imaging device 21 and the condensing microlens 23). Even when the relative position of each of the image pickup devices is shifted, the unique shading information of each color of RGB corresponding to each solid-state image pickup device 21 (each pixel unit) for each image pickup device is stored, and the color based on this unique shading information is stored. A shading correction coefficient can be calculated. At the time of shooting, color shading correction is performed based on the color shading correction coefficient for each individual imaging device, so if the shading characteristics are asymmetric about the optical axis or complex for each color, variation in manufacturing process Even when there are individual differences among image capturing devices, such as when the shading characteristics differ from color filter to color filter, the color shading characteristics can be corrected more accurately. Absent.

  Therefore, according to the color shading correction apparatuses 41A to 41C of the first to third embodiments, the unique shading information storage units 411aA to 411aC for storing the unique shading information of each color included in each imaging apparatus are provided. Based on the information, the color shading correction coefficient creation units 411bA to 411bC can calculate the color shading correction coefficient for each color. At the time of shooting, color shading correction of the captured image is performed by the color shading correction unit 412 based on the calculated color shading correction coefficient for each imaging device. This makes it possible to correct the shading characteristics more accurately even when the shading characteristics are asymmetric in the vertical and horizontal directions around the optical axis, or when the shading characteristics are different for each color filter due to variations in the manufacturing process.

  Although not specifically described in the first embodiment, a unique shading information storage is provided in which subjects having uniform colors and brightness are photographed by the imaging device, and the unique shading information of each color is stored for each imaging device. Unit 411aA, a color shading correction coefficient creation unit 411bA that creates a unique color shading correction coefficient for each imaging device based on color shading characteristics obtained from the unique shading information of each color, and captured image data using the color shading correction coefficient If the color shading correction unit 412 that performs color shading correction for the color filter, the shading characteristics are asymmetrical about the optical axis, and the shading characteristics differ for each color filter due to variations in manufacturing processes. Color shading even in cases Characteristics can achieve the object of the present invention can be more accurately corrected.

  Further, in the first embodiment, the unique shading information storage unit 411aA, as the unique shading information of each imaging device, pixel data when a subject having a uniform color and brightness is photographed, and a standard corresponding to this pixel data. Although the case where the difference from the pixel data of the shading characteristic data is stored has been described, the present invention is not limited to this, and the case where a subject with uniform color and brightness is photographed by the imaging device as the unique shading information storage unit 411aA. A ratio (for example, second color signal / first color signal) between the first color signal of two or more pixels and the second color signal of the standard shading characteristic data corresponding to the first color signal is stored as inherent shading information. It may be the case. Further, the unique shading information storage unit 411aA stores, as unique shading information, pixel data of each color of two or more colors when a subject having a uniform color and brightness is photographed as unique shading information of each imaging apparatus. Also good. For example, when correcting R (red) and G (green), it is also possible to calculate R standard shading characteristic data and G standard shading characteristic data, and store and correct the respective values. Even when B (blue) is corrected, the standard shading characteristic data of B can be calculated, and the respective R, G, and B values can be stored and corrected.

  In this case, the color shading correction coefficient creation unit 411bA calculates the color shading correction coefficient by dividing the unique shading information by the standard shading information of each color. In the case of a difference, the color shading correction coefficient creation unit 411bA calculates a color shading correction coefficient as an inverse function of the color shading characteristics obtained by adding standard shading information of each color to the inherent shading information.

  Furthermore, in Embodiments 1 to 3 described above, the unique shading information storage units 411aA to 411aC have been described as storing the unique shading information of each pixel of two or more colors that the imaging device has. The color may include at least two primary colors of R (red), G (green), and B (blue).

  In the first to third embodiments, the shading information is stored in the inherent shading information storage unit or the standard shading information storage unit of the digital camera. This shading information is stored in a place other than the digital camera (external shading information control). It is also possible to perform color shading correction using the color shading information stored in an external memory of the apparatus.

  Further, in the first to third embodiments, shading information is stored for each of the RGB colors, a color shading correction coefficient is calculated, and a color shading correction process is performed for each color. Correction processing may be performed on the image.

  Furthermore, in the second embodiment, the intrinsic shading information is approximated to a quadratic function to derive the optical center position and the like. However, the present invention is not limited to this, and a non-linear function other than the quadratic function may be used.

  In the second embodiment, the stored unique shading information is set to pixel data at diagonal positions (two locations) as shown in FIG. 6. Pixel data at two arbitrary points on the same axis and two arbitrary points on the same vertical axis are stored as inherent shading information, and the optical center position in the vertical direction is obtained from the two points on the same vertical axis, and on the same horizontal axis. The optical center position in the horizontal direction may be obtained from these two points.

  Further, in the second embodiment, the stored inherent shading information is set to pixel data at diagonal positions (two locations). However, the present invention is not limited to this, and an arbitrary position that is point-symmetric on the captured image is used. Pixel data may be stored.

Further, in the second embodiment, the optical center position (the center position of the optical lens) b ₀ and the optical center level c ₀ are calculated with the inclination a = a ₀ of the color shading characteristic, but the optical center position b = b _0. As described above, the shading characteristic slope a ₀ and the optical center level c ₀ may be calculated. Furthermore, it is also possible to calculate the _{a 0} and _{b 0} as c = _{c 0.}

  Furthermore, in the third embodiment, the inherent shading information to be stored is set to pixel data at grid positions as shown in FIG. 10, but the present invention is not limited to this, and pixel data at arbitrary positions may be stored. Good.

  In the third embodiment, linear interpolation using two points of pixel data is performed as an interpolation method. However, the present invention is not limited to this, and linear interpolation using three or more points of pixel data or non-linear using multiple points of pixel data. Interpolation or the like may be performed.

  As mentioned above, although this invention has been illustrated using preferable Embodiment 1-3 of this invention, this invention should not be limited and limited to this Embodiment 1-3. It is understood that the scope of the present invention should be construed only by the claims. It is understood that those skilled in the art can implement an equivalent range based on the description of the present invention and the common general technical knowledge from the description of specific preferred embodiments 1 to 3 of the present invention. Patents, patent applications, and documents cited herein should be incorporated by reference in their entirety, as if the contents themselves were specifically described herein. Understood.

  The present invention relates to color shading of an imaging device for correcting color shading characteristics in an imaging device such as a digital camera using a solid-state imaging device such as a CCD type image sensor or a CMOS type image sensor, or a camera for portable electronic information equipment. In the field of the correction device, the image pickup device including the shading correction device, and the color shading correction method of the image pickup device, a subject having a uniform color and brightness is photographed by the image pickup device and picked up from the unique shading information of each color In order to perform color shading correction by obtaining a unique color shading correction coefficient for each apparatus, the relative position between the optical lens and the imaging element (or / and the solid-state imaging element 21 and the condensing microlens 23 in the manufacturing process of the imaging apparatus). Relative position) and color shading characteristics If the case is asymmetric as heart and is complicated, even in a case where the color shading characteristics for each color filter is different due to variations in manufacturing process, it is possible to more accurately shading correction color shading characteristics.

It is a block diagram which shows the example of a basic composition of the color shading correction apparatus of the imaging device of this invention. It is a flowchart for demonstrating each process sequence of the color shading correction method using the color shading correction apparatus of FIG. (A) is a graph which shows an example of the shading characteristic of input RGB each color signal of correction object, (b) is a graph which shows an example of the color shading correction coefficient of RGB each color, (c) is (a) 4 is a graph showing the result of correcting the color shading characteristics by multiplying the color shading characteristic data of the input RGB color signal shown in FIG. 4B by the color shading correction coefficient shown in FIG. It is a block diagram which shows the principal part structural example of the digital camera which concerns on Embodiment 1 of this invention. 5 is a flowchart for explaining each processing procedure of a color shading correction method in the digital camera of FIG. 4. (A) is a graph showing an example of the standard shading characteristic data stored in the standard shading information storage unit and the shading characteristic data of each color of RGB obtained from the captured image data. (B) It is a graph which shows an example of the specific shading characteristic data memorize | stored in a specific shading information storage part. (A) is a graph which shows an example of the shading characteristic data of each color of RGB, (b) is a graph which shows an example of the color shading correction coefficient which is the inverse function, (c) is (a). 5 is a graph showing a result of correcting a color shading characteristic by multiplying the indicated shading characteristic data by the color shading correction coefficient shown in FIG. It is a flowchart for demonstrating each process sequence of the color shading correction method in the digital camera which concerns on Embodiment 2 of this invention. 6 is a graph showing an example of the position of pixel data stored in a unique shading information storage unit in a digital camera according to Embodiment 2 of the present invention. It is a graph which shows an example of the shading characteristic estimated from the standard shading characteristic and measurement data in the digital camera which concerns on Embodiment 2 of this invention. It is a block diagram which shows the principal part structural example of the digital camera which concerns on Embodiment 3 of this invention. 12 is a flowchart for explaining each processing procedure of the color shading correction method in the digital camera of FIG. 11. 12 is a graph showing an example of the position of pixel data stored in a unique shading information storage unit in the digital camera of FIG. FIG. 12 is a diagram illustrating color shading characteristics predicted by linearly interpolating measurement data in the digital camera of FIG. 11. It is a flowchart for demonstrating each process sequence of the conventional color shading correction method. (A) is a graph showing an example of shading characteristic data of each color of RGB in the color shading correction method of FIG. 15, and (b) is a graph showing an example of a color shading correction coefficient common to RGB which is an inverse function thereof. And (c) is a graph showing the result of correcting the color shading characteristics by multiplying the shading characteristic data shown in (a) by the color shading correction coefficient shown in (b).

Explanation of symbols

1 Optical lens 2 CCD
DESCRIPTION OF SYMBOLS 21 Solid-state image sensor 22 Color filter 23 Micro lens 24 IR cut filter 3 CCD signal processing part / drive control part 4A-4C Image processing apparatus 41, 41A-41C Color shading correction apparatus 411, 411A-411C Color shading correction control part 411a, 411aA, 411aB, 411aC Specific shading information storage unit 411a 'Standard shading information storage unit 411a "Shading information interpolation unit 411b, 411bA, 411bB, 411bC Color shading correction coefficient creation unit 412 Color shading correction unit 42 Image processing unit 43 Video signal output unit 10, 10A-10C Digital camera

Claims (36)

A unique shading information storage means for photographing a subject with uniform color and brightness with an imaging device, and storing unique shading information for each color for each imaging device;
Color shading correction coefficient creating means for creating a unique color shading correction coefficient for each imaging device based on color shading characteristics obtained from the unique shading information of each color;
A color shading correction apparatus for an imaging apparatus, comprising color shading correction means for performing color shading correction on captured image data using the color shading correction coefficient.    2. The color shading correction apparatus for an image pickup apparatus according to claim 1, wherein the unique shading information storage unit stores unique shading information for each of two or more pixels of the image pickup apparatus.   The unique shading information storage means includes pixel data obtained by photographing an object having a uniform color and brightness, and pixel data of standard shading characteristic data corresponding to the pixel data as unique shading information for each of the imaging devices. The color shading correction apparatus for an imaging apparatus according to claim 1, wherein a difference between the color shading correction apparatus and the image storage apparatus is stored.   The unique shading information storage means includes a color signal of two or more pixels when a subject with uniform color and brightness is photographed by the imaging device, and a color of standard shading characteristic data corresponding to the color signal. The color shading correction apparatus for an imaging apparatus according to claim 1, wherein a ratio with a signal or pixel data of each color of two or more colors is stored as the inherent shading information.   4. The color shading correction apparatus for an imaging apparatus according to claim 3, further comprising standard shading information storage means for storing standard shading information for each color of the imaging apparatus as the standard shading characteristic data.   6. The color shading correction apparatus for an image pickup apparatus according to claim 1, wherein the color shading correction coefficient creating means calculates the color shading correction coefficient based on standard shading information for each color and the unique shading information.   The color shading correction coefficient creating means calculates an inverse function of a shading characteristic of each color of two or more colors as a color shading correction coefficient based on the standard shading information of each color and the inherent shading information, respectively. 6. A color shading correction apparatus for an imaging apparatus according to 5.   The unique shading information storage means stores, as the unique shading information, pixel data at a point-symmetrical position for each of two or more colors when the imaging device captures a subject with uniform color and brightness. The color shading correction apparatus for an imaging apparatus according to claim 1.   The unique shading information storage means stores, as the unique shading information, pixel data at diagonal positions for each of two or more colors when the imaging device captures an object with uniform color and brightness. The color shading correction apparatus for an imaging apparatus according to claim 8.   The unique shading information storage unit is configured to store a position on the same horizontal axis and / or a position on the same vertical axis for each of two or more colors when the subject having a uniform color and brightness is photographed by the imaging device. The color shading correction apparatus for an imaging apparatus according to claim 8, wherein pixel data is stored as the inherent shading information.   11. The optical center position of color shading characteristics obtained from a color signal of a captured image or pixel data of each color of two or more colors is stored in the unique shading information storage means. The color shading correction apparatus of the image pickup apparatus described.   12. The optical center level of color shading characteristics obtained from a color signal of a captured image or pixel data of each color of two or more colors is stored in the unique shading information storage unit. The color shading correction apparatus of the image pickup apparatus described.   The slope of the color shading characteristic calculated | required from the color signal of the captured image, or the pixel data of each color of 2 or more colors is memorize | stored in the said intrinsic | native shading information storage means. Color shading correction device for an imaging device.   The color shading correction apparatus for an imaging apparatus according to any one of claims 1 and 8 to 10, wherein the unique shading information storage means stores a luminance level of two or more pixels of a captured image.   The color shading correction apparatus for an imaging apparatus according to claim 1, wherein a ratio of luminance levels of two or more pixels of a captured image is stored in the unique shading information storage unit.   The color shading correction apparatus for an imaging apparatus according to any one of claims 1 and 8 to 10, wherein the unique shading information storage means stores an optical center position of a color shading characteristic obtained from a luminance level of a captured image.   The color shading correction of the imaging apparatus according to any one of claims 1, 8, 10 and 16, wherein the unique shading information storage means stores an optical center level of a color shading characteristic obtained from a luminance level of a captured image. apparatus.   18. The color shading correction of the imaging apparatus according to claim 1, wherein the unique shading information storage unit stores a slope of a color shading characteristic obtained from a luminance level of a captured image. apparatus.   The color shading correction coefficient creating means calculates an optical center position and an optical center level of a color shading characteristic approximated based on the inherent shading information, and a color shading characteristic approximated based on these and standard shading information The difference between the optical center position and the optical center level is calculated, color shading characteristics corrected by shift and gain adjustment based on the calculated information and the standard shading information are calculated, and the corrected color The color shading correction apparatus for an imaging apparatus according to any one of claims 8 to 13 and 16 to 18, wherein an inverse function of a shading characteristic is calculated as a color shading correction coefficient.   The unique shading information storage means stores, as the unique shading information, each pixel data at an arbitrary position for each of two or more colors when the imaging device captures a subject with uniform color and brightness. The color shading correction apparatus for an imaging apparatus according to claim 1.   The unique shading information storage means stores, as the unique shading information, each pixel data of a grid-like position for each of two or more colors when a subject with uniform color and brightness is photographed by the imaging device. The color shading correction apparatus for an imaging apparatus according to claim 20.   Shading information interpolating means for obtaining color shading characteristics by linearly or non-linearly interpolating non-stored pixel data based on two or more adjacent pixel data stored in the unique shading information storage means The color shading correction apparatus for an imaging apparatus according to claim 20 or 21, further comprising:   The color shading correction apparatus for an imaging apparatus according to claim 22, wherein the color shading correction coefficient creating means calculates an inverse function of the color shading characteristic as a color shading correction coefficient.   The color of the imaging apparatus according to any one of claims 1, 6, 7, 19 and 23, wherein the color shading correction coefficient creating means is provided with a color shading correction coefficient storage means for storing the color shading correction coefficient. Shading correction device.   25. The imaging apparatus according to claim 1, wherein the color shading correction unit performs color shading correction by multiplying the input image data to be corrected by the color shading correction coefficient. Color shading correction device.   The imaging according to any one of claims 2, 4, 7 to 10, 20 and 21, wherein the two or more colors include at least two primary colors of R (red), G (green) and B (blue). Device color shading correction device.   The color shading correction apparatus for an imaging apparatus according to claim 19, wherein the approximated color shading characteristic is a quadratic function.   When the color signal of the pixels of two or more colors is the first color signal and the color signal of the standard shading characteristic data is the second color signal, the ratio is the second color signal / the first color signal. The color shading correction apparatus of the imaging device according to claim 4.   The color of the imaging apparatus according to claim 3, wherein the color shading correction coefficient creating unit calculates the color shading correction coefficient as an inverse function of a color shading characteristic obtained by adding standard shading information of each color to the unique shading information. Shading correction device.   5. The color shading correction apparatus for an imaging apparatus according to claim 4, wherein the color shading correction coefficient creating unit calculates the color shading correction coefficient by dividing the intrinsic shading information by standard shading information of each color.   31. A solid-state imaging device that photoelectrically converts light incident through an optical system for each pixel, and color shading correction of each image data that has been photoelectrically converted by the solid-state imaging device. An image pickup apparatus comprising the color shading correction apparatus according to any one of the above.   32. The imaging apparatus according to claim 31, wherein the solid-state imaging device is a CCD type image sensor or a CMOS type image sensor. A standard shading information storage step of storing standard shading information of the imaging apparatus in the standard shading information storage means;
A unique shading information storage step of storing in the unique shading information storage means the unique shading information of each pixel of two or more colors possessed by each imaging device;
A color shading correction coefficient creating step for calculating an inverse function of shading characteristics of two or more colors as a color shading correction coefficient based on each shading information stored in the standard shading information storage means and the unique shading information storage means;
A color shading correction method for an imaging apparatus, comprising: a color shading correction step for performing color shading correction based on a calculated color shading correction coefficient. A standard shading information storage step of storing standard shading information of the imaging apparatus in the standard shading information storage means;
A unique shading information storage step of storing in the unique shading information storage means the unique shading information of each pixel of two or more colors possessed by each imaging device;
An optical center position and an optical center level of the color shading characteristics approximated based on the specific shading information are calculated, and an optical center position and an optical center level of the color shading characteristics approximated based on these and the standard shading information The color shading characteristics corrected by shift and gain adjustment are calculated based on the calculated information and the standard shading information, and an inverse function of the corrected color shading characteristics is calculated by color shading. A color shading correction coefficient creation step to be calculated as a correction coefficient;
A color shading correction method for an imaging apparatus, comprising: a color shading correction step for performing color shading correction based on a calculated color shading correction coefficient. A unique shading information storage step of storing in the unique shading information storage means the unique shading information of each pixel of two or more colors possessed by each imaging device;
A shading information interpolation step of calculating color shading characteristics by interpolating other unique shading information that is not stored using the unique shading information stored in the unique shading information storage means;
A color shading correction coefficient creating step for calculating an inverse function of the color shading characteristics including the interpolated intrinsic shading information as a color shading correction coefficient;
A color shading correction method for an imaging apparatus, comprising: a color shading correction step for performing color shading correction based on a calculated color shading correction coefficient.   A solid-state image sensor that photoelectrically converts light incident through the optical system for each pixel, and a color shading correction device that performs color shading correction of each image data captured by photoelectric conversion by the solid-state image sensor 36. The imaging apparatus according to any one of claims 33 to 35, wherein the unique shading information is obtained by photographing each subject having a uniform color and brightness for each imaging apparatus when the imaging apparatus provided is manufactured. Color shading correction method.

Images