JP2009303020A - Image capturing apparatus and defective pixel correcting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image capturing apparatus and defective pixel correcting method capable of suppressing a processing time, that is required for correcting a defective pixel, from being prolonged. <P>SOLUTION: A plurality of photoelectric conversion elements are composed of a plurality of first photoelectric conversion elements and a plurality of second photoelectric conversion elements, and the plurality of first photoelectric conversion elements and the plurality of second photoelectric conversion elements have the same array so that photoelectric conversion elements detecting the same color component are adjacent to each other. When either the first photoelectric conversion element or the second photoelectric conversion element is a defective pixel, a pixel signal detected by any one of the other photoelectric conversion elements being proximate to the defective pixel and detecting the same color component is captured. The pixel signal is used as it is as a defective pixel signal of the defective pixel or when photodetection sensitivity of the first photoelectric conversion elements is different from that of the second photoelectric conversion elements, correction processing is performed only by multiplying a sensitivity coefficient corresponding to the photodetection sensitivity. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an imaging apparatus and a defective pixel correction method for correcting defective pixels of an imaging device provided in an imaging apparatus such as a digital camera.

  An imaging device such as a digital camera performs imaging by forming an image of a subject on an image sensor and capturing image information representing the subject. As the image sensor, a CCD image sensor, a CMOS image sensor, or the like is used. Many pixels are arranged in the image sensor, and the image sensor is manufactured by forming a large number of photoelectric conversion elements such as photodiodes on a semiconductor substrate. When manufacturing an image sensor, a defective pixel incapable of capturing a pixel signal may be generated due to impurities mixed into a semiconductor substrate.

  Conventionally, as a method for correcting a defective pixel of an image sensor, there is a method shown in the following patent document, for example.

  Patent Document 1 describes a camera including an imaging device in which pixels composed of a composite of a main pixel and a plurality of pixels are arranged, the main pixel is a defective pixel, and the signal level of surrounding pixels is a predetermined luminance. If the signal level represents a luminance higher than the level, the pixel value of the defective pixel is obtained based on the pixel value obtained by the sub-pixel, and the sub-pixel is the defective pixel and the main pixel is the normal pixel In this case, it is described that the pixel value of the defective pixel is obtained based on the pixel value obtained from the main pixel. The main pixel is a pixel having a relatively large area and high sensitivity to incident light, and the sub-pixel is a pixel having a relatively small area and low sensitivity to incident light.

  Patent Document 2 describes a CCD type imaging device that includes a plurality of pixels having main pixels and sub-pixels having different sensitivities, and receives incident subject light and converts them into electrical signals. If one of the main pixel and the sub-pixel is defective, the pixel value of the defective pixel is corrected using the other pixel value as part of the correction processing data.

JP 2004-120525 A JP 2004-247946 A

When correcting a defective pixel, the pixel value of the defective pixel is calculated by a calculation process using pixel signals around the defective pixel, so even if the average value of the surrounding pixel values is corrected, the calculation process takes time. Is required.
In addition, when correcting defective pixels between pixels with different sensitivities, the pixel value of the defective pixel is calculated after correcting for the difference in sensitivity, but if the sensitivity difference is large, the correction is performed with high accuracy. I can't do it.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an imaging apparatus and a defective pixel correction method capable of suppressing an increase in processing time required for correcting a defective pixel. .

  According to the defective pixel correction method of the present invention, a plurality of photoelectric conversion elements for detecting light of a color component necessary for generating color image data are provided, and the plurality of photoelectric conversion elements are a plurality of first photoelectric conversion elements. And a plurality of second photoelectric conversion elements, wherein the plurality of first photoelectric conversion elements and the plurality of second photoelectric conversion elements are in the same array and detect the same color component Is a defective pixel correction method for an image sensor arranged so as to be adjacent to each other, and when either one of the first photoelectric conversion element and the second photoelectric conversion element is a defective pixel, Among the other photoelectric conversion elements, a pixel signal that is close to the defective pixel and detected by the photoelectric conversion element that detects the same color component is obtained, and the pixel signal is used as it is as the pixel signal of the defective pixel. Or Of when the receiving sensitivity of the photoelectric conversion element and the second photoelectric conversion element are different only multiplies the sensitivity coefficient corresponding to the light receiving sensitivity, the correction process.

  In the defective pixel correction method of the present invention, when the photoelectric conversion element that is close to the defective pixel and detects the same color component is defective, the first photoelectric conversion element or the second photoelectric conversion element The pixel signal of the defective pixel is obtained from the photoelectric conversion element closest to the defective pixel and containing the defective pixel, and having the same color component, and the pixel signal of the defective pixel is obtained based on the pixel signal. Calculate.

  In the defective pixel correction method of the present invention, the first photoelectric conversion element and the second photoelectric conversion element are respectively arranged in a square lattice shape in a row direction and a column direction, and the first photoelectric conversion element and the second photoelectric conversion element are arranged. The photoelectric conversion elements are arranged at positions shifted by about ½ of the arrangement pitch in the row direction and the column direction.

  In the defective pixel correction method of the present invention, the first photoelectric conversion element and the second photoelectric conversion element are arranged in a square lattice so as to be inclined with respect to the row direction and the column direction, respectively, and the first photoelectric conversion element is arranged. Each second photoelectric conversion element is disposed between the row direction and the column direction of the conversion elements.

The imaging apparatus according to the present invention includes a plurality of photoelectric conversion elements that detect light of a color component necessary for generating color image data, and the plurality of photoelectric conversion elements include a plurality of first photoelectric conversion elements and a plurality of photoelectric conversion elements. The plurality of first photoelectric conversion elements and the plurality of second photoelectric conversion elements are in the same array, and the photoelectric conversion elements that detect the same color component are mutually connected. An imaging device including an imaging device arranged so as to be adjacent to each other,
When one of the first photoelectric conversion element and the second photoelectric conversion element is a defective pixel, the other photoelectric conversion element is close to the defective pixel and has the same color component. The pixel signal detected by the photoelectric conversion element to be detected is acquired and the pixel signal is used as it is as the pixel signal of the defective pixel, or the detection sensitivity of the first photoelectric conversion element and the second photoelectric conversion element is If they are different from each other, a defective pixel correction unit that performs correction processing only by multiplication of a sensitivity coefficient corresponding to the detection sensitivity is provided.

  According to the present invention, a pixel signal detected by a photoelectric conversion element that is close to a defective pixel and detects the same color component is acquired, and the pixel signal is used as a pixel signal of the defective pixel. There is no need to do it. For this reason, it can suppress that the processing time concerning correcting a defective pixel becomes long.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram illustrating a schematic configuration of a digital camera which is an example of an imaging apparatus that performs the defective pixel correction method of the present invention.
The imaging system of the digital camera includes a photographic lens 1, a CCD type solid-state imaging device 5, a diaphragm 2 provided therebetween, an infrared cut filter 3, and an optical low-pass filter 4. In the present embodiment, an example using the CCD solid-state imaging device 5 will be described. However, the imaging device in which defective pixels are corrected by the defective pixel correction method of the present invention is not limited to the CCD solid-state imaging device 5. For example, the present invention can be applied to a CMOS type image sensor.

  A system control unit 11 that performs overall control of the electrical control system of the digital camera controls the flash light emitting unit 12 and the light receiving unit 13 and controls the lens driving unit 8 to adjust the position of the photographing lens 1 to the focus position and zoom. The exposure amount is adjusted by adjusting the aperture amount of the aperture 2 via the aperture drive unit 9.

  The system control unit 11 drives the solid-state image sensor 5 via the image sensor driving unit 10 and outputs a subject image captured through the photographing lens 1 as a color signal. An instruction signal from the user is input to the system control unit 11 through the operation unit 14.

  The electric control system of the digital camera further includes an analog signal processing unit 6 that performs analog signal processing such as correlated double sampling processing connected to the output of the solid-state imaging device 5, and RGB output from the analog signal processing unit 6. And an A / D conversion circuit 7 for converting the color signals into digital signals, which are controlled by the system control unit 11.

  The electric control system of the digital camera further performs image data by performing black level correction, interpolation calculation, gamma correction calculation, RGB / YC conversion processing, and the like with the main memory 16 and the memory control unit 15 connected to the main memory 16. A digital signal processing unit 17 for generating a digital signal, a compression / decompression processing unit 18 for compressing the image data generated by the digital signal processing unit 17 into a JPEG format or expanding the compressed image data, and integrating the photometric data into a digital signal A display to which an integration unit 19 for obtaining a gain of white balance correction performed by the processing unit 17, an external memory control unit 20 to which a detachable recording medium 21 is connected, and a liquid crystal display unit 23 mounted on the back of the camera or the like is connected. And a control unit 22, which are connected to each other by a control bus 24 and a data bus 25, and in accordance with a command from the system control unit 11. It is controlled Te.

FIG. 2 is a schematic plan view showing a configuration example of the solid-state imaging device 5 shown in FIG.
The solid-state imaging device 5 is a photoelectric conversion device that detects light in the red (R) wavelength region (R light) arranged in a square lattice pattern in the row direction X on the semiconductor substrate 50 and the column direction Y orthogonal thereto. 51R (indicated by the letter “R” in the figure), photoelectric conversion element 51G for detecting light (G light) in the green (G) wavelength region (indicated by the letter “G” in the figure) A plurality of first photoelectric conversion elements composed of photoelectric conversion elements 51B that detect light in the blue (B) wavelength range (B light) (labeled with “B” in the drawing); A photoelectric conversion element 51r for detecting R light arranged in a square lattice pattern in a row direction X on the semiconductor substrate 50 and in a column direction Y orthogonal thereto (indicated by the letter “r” in the figure); Photoelectric conversion element 51g for detecting G light (the letter “g” is attached in the figure), photoelectric conversion element 51b for detecting B light (“b” in the figure) A plurality of second photoelectric conversion elements, and the first photoelectric conversion element and the second photoelectric conversion element are approximately ½ of the respective photoelectric conversion element array pitch. Only in positions shifted in the row direction X and the column direction Y.

  The photoelectric conversion elements of the first photoelectric conversion element and the second photoelectric conversion element are arranged so that the photoelectric conversion elements that detect the same color component are adjacent to each other. That is, in the diagonal direction of the row direction X and the column direction Y, the photoelectric conversion element 51R is adjacent to the photoelectric conversion element 51r, the photoelectric conversion element 51G is adjacent to the photoelectric conversion element 51g, and the photoelectric conversion element 51B is adjacent to the photoelectric conversion element 51b. Adjacent.

  The arrangement pitch of the photoelectric conversion elements of the first photoelectric conversion element is the same as the arrangement pitch of the photoelectric conversion elements of the second photoelectric conversion element. The photoelectric conversion element is composed of, for example, a photodiode.

  A color filter is provided above each photoelectric conversion element of the first photoelectric conversion element, and the arrangement of the color filters is a Bayer arrangement. A color filter is similarly provided above each photoelectric conversion element of the second photoelectric conversion element, and this color filter array is also a Bayer array.

  The light receiving sensitivity of each photoelectric conversion element of the first photoelectric conversion element is higher than the light receiving sensitivity of each photoelectric conversion element of the second photoelectric conversion element. In order to change the light receiving sensitivity of the photoelectric conversion element, the light receiving surface of each photoelectric conversion element of the first photoelectric conversion element and the light receiving surface of each photoelectric conversion element of the second photoelectric conversion element have different areas. The condensing area may be changed or the exposure time of the photoelectric conversion element may be changed by a microlens provided above the photoelectric conversion element. Moreover, the light reception sensitivity of each photoelectric conversion element of the first photoelectric conversion element and the light reception sensitivity of each photoelectric conversion element of the second photoelectric conversion element may be the same.

  The array of the photoelectric conversion elements of the first photoelectric conversion element is arranged in the column direction Y with a GR photoelectric conversion element array that is a photoelectric conversion element array including a photoelectric conversion element 51G and a photoelectric conversion element 51R aligned in the column direction Y. BG photoelectric conversion element arrays, which are photoelectric conversion element arrays composed of photoelectric conversion elements 51B and 51G, are alternately arranged in the row direction X. In addition, the arrangement of the photoelectric conversion elements of the first photoelectric conversion element includes a GB photoelectric conversion element row, which is a photoelectric conversion element row including the photoelectric conversion elements 51G and 51B arranged in the row direction X, and the row direction X. RG photoelectric conversion element rows, which are photoelectric conversion element rows composed of photoelectric conversion elements 51R and 51G arranged in a row, are alternately arranged in the column direction Y.

  The arrangement of the photoelectric conversion elements of the second photoelectric conversion elements is arranged in the column direction Y with a gr photoelectric conversion element array that is a photoelectric conversion element array composed of the photoelectric conversion elements 51 g and the photoelectric conversion elements 51 r aligned in the column direction Y. The bg photoelectric conversion element array, which is a photoelectric conversion element array including the photoelectric conversion elements 51b and 51g, is alternately arranged in the row direction X. In addition, the arrangement of the photoelectric conversion elements of the second photoelectric conversion element includes a gb photoelectric conversion element row, which is a photoelectric conversion element row composed of the photoelectric conversion elements 51g and the photoelectric conversion elements 51b arranged in the row direction X, and the row direction X. The rg photoelectric conversion element rows, which are photoelectric conversion element rows composed of the photoelectric conversion elements 51r and 51g arranged in parallel, are alternately arranged in the column direction Y. In the present embodiment, the photoelectric conversion element 51B and the photoelectric conversion element 51b in the upper right in FIG. 2 of the photoelectric conversion element 51B form a pair, and the photoelectric conversion element 51G and the photoelectric conversion element 51g in the upper right in FIG. 2 of the photoelectric conversion element 51G. And the photoelectric conversion element 51R and the photoelectric conversion element 51r on the upper right in FIG. 2 of the photoelectric conversion element 51R form a pair.

  On the right side of each photoelectric conversion element array, a vertical charge transfer path 54 for transferring charges accumulated in the photoelectric conversion elements constituting each photoelectric conversion element array in the column direction Y (only a part is shown in FIG. 2). Is formed). The vertical charge transfer path 54 is formed by, for example, n-type impurities injected into a p-well layer formed on an n-type silicon substrate.

  Above the vertical charge transfer path 54, transfer electrodes V <b> 1 to V <b> 8 are formed to which an eight-phase transfer pulse for controlling transfer of charges read out to the vertical charge transfer path 54 is applied by the image sensor driving unit 10. ing.

  The transfer electrodes V1 to V8 are arranged so as to meander between the photoelectric conversion element rows in the row direction X so as to avoid the photoelectric conversion elements constituting them. On the upper side of the gb photoelectric conversion element row, a transfer electrode V8 and a transfer electrode V1 are arranged in this order from the photoelectric conversion element row side between adjacent photoelectric conversion element rows. On the lower side of the gb photoelectric conversion element row, the transfer electrode V2 and the transfer electrode V3 are arranged in order from the gb photoelectric conversion element row side between the adjacent photoelectric conversion element rows. On the upper side of the rg photoelectric conversion element row, a transfer electrode V4 and a transfer electrode V5 are arranged in this order from the photoelectric conversion element row side between adjacent photoelectric conversion element rows. On the lower side of the rg photoelectric conversion element row, a transfer electrode V6 and a transfer electrode V7 are arranged in order from the rg photoelectric conversion element row side between the adjacent photoelectric conversion element rows.

  Between each photoelectric conversion element and the vertical charge transfer path 54 corresponding to the photoelectric conversion element, a charge reading unit 55 for reading the charge generated in each photoelectric conversion element to the vertical charge transfer path 54 is provided. The charge readout unit 55 is formed by a part of a p-well layer formed on an n-type silicon substrate, for example. The charge readout unit 55 is provided in the same direction (in the diagonally lower right direction in the drawing) with respect to each photoelectric conversion element.

  A transfer electrode V2 is formed above the charge reading unit 55 corresponding to each photoelectric conversion element in the gb photoelectric conversion element row, and a read pulse is applied to the transfer electrode V2 to each photoelectric conversion element in the gb photoelectric conversion element row. The accumulated charges can be read out to the vertical charge transfer path 54 on the right side of each photoelectric conversion element.

  A transfer electrode V4 is formed above the charge reading unit 55 corresponding to each photoelectric conversion element in the GB photoelectric conversion element row, and a read pulse is applied to each of the photoelectric conversion elements in the GB photoelectric conversion element row. The accumulated charges can be read out to the vertical charge transfer path 54 on the right side of each photoelectric conversion element.

  A transfer electrode V6 is formed above the charge reading unit 55 corresponding to each photoelectric conversion element in the rg photoelectric conversion element row, and by applying a read pulse to the transfer electrode V6, the transfer electrode V6 is applied to each photoelectric conversion element in the rg photoelectric conversion element row. The accumulated charges can be read out to the vertical charge transfer path 54 on the right side of each photoelectric conversion element.

  A transfer electrode V8 is formed above the charge reading unit 55 corresponding to each photoelectric conversion element in the RG photoelectric conversion element row, and a read pulse is applied to each of the photoelectric conversion elements in the RG photoelectric conversion element row. The accumulated charges can be read out to the vertical charge transfer path 54 on the right side of each photoelectric conversion element.

  A horizontal charge transfer path 57 for transferring the charges transferred through the vertical charge transfer path 54 in the row direction X is connected to the vertical charge transfer path 54. The horizontal charge transfer path 57 is connected to the horizontal charge transfer path 57. Is connected to an output amplifier 58 that converts the charge transferred to a voltage signal and outputs the voltage signal.

  The transfer electrodes (V2, V4, V6, V8) above the charge reading unit 55 are respectively provided with a middle level (VM, for example, 0V) transfer pulse VM for forming a packet for accumulating charges in the vertical charge transfer path 54. And a transfer pulse VL having a low level (VL, for example, −8 V) lower than the VM for forming a barrier of the packet in the vertical charge transfer path 54, and a charge from each photoelectric conversion element to the vertical charge transfer path 54. Or a read pulse having a level higher than VM (VH, for example, 15 V) can be applied. Any transfer pulse of VL and VM can be applied to the transfer electrodes (V1, V3, V5, V7) other than the transfer electrodes (V2, V4, V6, V8) above the charge reading unit 55. .

  The solid-state imaging device 5 of the present embodiment has a shooting mode in which first image information is generated with a signal obtained from the first photoelectric conversion element, and second image information is generated with a signal obtained from the second photoelectric conversion element. Can be executed. According to this shooting mode, the first photoelectric conversion element and the second photoelectric conversion element have different light receiving sensitivities, so that an image having a wide dynamic range is generated by combining the first image information and the second image information. Can do.

Next, the procedure of the defective pixel correction method for the solid-state imaging device 5 in the shooting mode will be described. FIG. 3 is a flowchart showing the procedure of the defective pixel correction method.
First, the photographing mode is set and photographing is performed. When the exposure period by this photographing is completed, the transfer pulse VM is applied to the transfer electrodes V4 and V8, and the charge corresponding to each photoelectric conversion element of the first photoelectric conversion element. Accumulated packets are formed under the transfer electrodes V4 and V8. In this state, a read pulse is applied to each of the transfer electrodes V4 and V8, and the charge generated in each photoelectric conversion element of the first photoelectric conversion element is transferred to the charge accumulation packet formed corresponding to each photoelectric conversion element. Read out. Next, a transfer pulse of a predetermined pattern is applied to the transfer electrodes V1 to V8, and the charge read out in the charge accumulation packet is transferred to the horizontal charge transfer path 57 and transferred from here to the output unit 58, where It is converted and output, and the first field ends. Hereinafter, the signal obtained in the first field is also referred to as first image information.

  Next, the transfer pulse VM is applied to the transfer electrodes V2 and V6, respectively, and a charge accumulation packet corresponding to each photoelectric conversion element of the second photoelectric conversion element is formed below the transfer electrodes V2 and V6. Thereafter, the read pulse is not applied to the transfer electrodes V2 and V6, and the transfer pulse having the same predetermined pattern as that of the first field is applied to the transfer electrodes V1 to V8, and the dark current component existing in the charge accumulation packet is applied. Are transferred to the horizontal charge transfer path 57 in the same transfer pattern as the charge in the first field, transferred from here to the output unit 58, converted into a signal and output here, and the second field is completed. Hereinafter, the signal obtained in the second field is also referred to as second image information.

  Thus, the first image information detected by the first photoelectric conversion element and the second image information detected by the second photoelectric conversion element are acquired (step S11).

  By transferring the charge accumulation packet in the first field and the second field with the same transfer pattern, the first image information and the second image information can be obtained under the same conditions as much as possible.

  The image information obtained in each of the first field and the second field is digitally converted and then input to the digital signal processing unit 17. The digital signal processing unit 17 detects defective pixels of the first photoelectric conversion element based on the first image information obtained in the first field, and the second image information obtained in the second field. Based on the above, defective pixels of the second photoelectric conversion element are detected (step S12).

  Next, a process of comparing the defective pixel detected by the first image information with the defective pixel detected by the second image information is performed. 4 to 6 are schematic diagrams illustrating a part of the array of photoelectric conversion elements and the color components of light detected by each photoelectric conversion element.

FIG. 4 is a schematic diagram illustrating a case where the photoelectric conversion element that detects the G light of the first photoelectric conversion element is a defective pixel.
As shown in FIG. 4, when the photoelectric conversion element indicated by diagonal lines is a defective pixel, a photoelectric conversion element that detects the same color component adjacent to the defective pixel (detects g light circled in FIG. 4). It is determined whether or not the photoelectric conversion element to be defective is defective (step S13). When the photoelectric conversion element that detects the adjacent g light is not a defective pixel, the pixel signal detected by the photoelectric conversion element that detects the g light is acquired (step S15). Here, since the photoelectric conversion elements for detecting G light and the photoelectric conversion elements for detecting g light are alternately arranged from the upper right direction to the lower left direction in FIG. 4, they are paired with the photoelectric conversion elements for detecting G light. The photoelectric conversion element to be used may be either the upper right side or the lower left side. When one is a defective pixel, the opposite pixel may be used as a substitute for the pair of photoelectric conversion elements.

FIG. 5 is a schematic diagram illustrating a case where the photoelectric conversion element that detects g light of the second photoelectric conversion element is a defective pixel.
As shown in FIG. 5, when the photoelectric conversion element indicated by hatching is a defective pixel, the photoelectric conversion element that detects the same color component adjacent to the defective pixel (the G light circled in FIG. 5 is detected). It is determined whether or not the photoelectric conversion element to be defective is defective (step S14). If the photoelectric conversion element that detects the adjacent G light is not a defective pixel, the pixel signal detected by the photoelectric conversion element that detects the G light is acquired (step S16).

  On the other hand, as shown in FIG. 6, when both the photoelectric conversion element for detecting the G light indicated by the oblique lines and the photoelectric conversion element for detecting the g light adjacent to the photoelectric conversion element for detecting the G light are defective pixels. Is the closest photoelectric conversion element arranged around the defective pixel and detects the same G light (a photoelectric conversion element that detects G light circled in FIG. 6). A pixel signal is acquired (step S17). In this embodiment, the case where the photoelectric conversion element that detects G light or g light is a defective pixel has been described as an example. However, the case where the photoelectric conversion element that detects R light or r light is a defective pixel or B The same correction can be made when the photoelectric conversion element for detecting light or b light is a defective pixel.

  Thereafter, correction processing is performed by using the pixel signals acquired in steps S15 to S17 as they are as they are as pixel signals of defective pixels (step S18). At this time, the obtained pixel signal is used as it is as the pixel signal of the defective pixel, or when the light receiving sensitivities of the first photoelectric conversion element and the second photoelectric conversion element are different, the sensitivity corresponding to the light receiving sensitivity is used. The time required for the arithmetic processing can be reduced only by the multiplication of the coefficients. When the light receiving sensitivities of the first photoelectric conversion element and the second photoelectric conversion element are the same, no multiplication of sensitivity coefficients is necessary, so that no arithmetic processing is required. As described above, by using the pixel signal of the normal photoelectric conversion element paired with the defective pixel as it is as the pixel signal of the defective pixel, the arithmetic processing related to the correction processing can be reduced or omitted.

  The digital signal processing unit 17 generates color image data using the corrected first image information and second image information. The generated color image data is compressed and then recorded on the recording medium 21.

  According to the correction method of the present embodiment, the first image information and the second image information based on the pixel signals detected by the first photoelectric conversion element and the second photoelectric conversion element are compared with each other. When there is a defective pixel in one of the image information and the second image information, the pixel signal of the other photoelectric conversion element adjacent to the defective pixel is used. In this way, it is not necessary to calculate the pixel value of the defective pixel by the arithmetic processing using the pixel signal around the defective pixel as in the conventional correction method.

  Note that the solid-state imaging device of the present embodiment has a drive for generating image data only with image information obtained from the first photoelectric conversion element and the first photoelectric conversion element when the correction process of the defective pixel is not performed. The driving in the case of generating image data with the first image information obtained from the second image information obtained from the second photoelectric conversion element can be arbitrarily switched.

  Note that, as described above, driving when image data is generated using only image information obtained from the first photoelectric conversion element may be performed in a high-speed shooting mode such as moving image shooting.

  In the configuration shown in FIG. 2, the present invention can also be applied to a configuration in which each photoelectric conversion element of the second photoelectric conversion element is changed to a photoelectric conversion element provided with a luminance filter above the light receiving surface.

  The luminance filter is a filter having spectral characteristics correlated with light luminance information. This luminance filter corresponds to an ND filter, a transparent filter, a white filter, a gray filter, or the like, but the configuration in which light is directly incident on the light receiving surface without providing anything above the light receiving surface of the photoelectric conversion element is also possible. It can be said that a filter is provided.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the present embodiment, the configuration of the imaging device is the same as that in the first embodiment.
FIG. 7 is a diagram schematically illustrating an example of an array of photoelectric conversion elements of the image sensor according to the present embodiment. As shown in FIG. 7, the first photoelectric conversion element and the second photoelectric conversion element are arranged in a square lattice so as to be inclined by 45 degrees with respect to the row direction X and the column direction Y, respectively. Each second photoelectric conversion element is arranged between the row direction X and the column direction Y of the element. Further, above each photoelectric conversion element, a 2 × 2 array of the first photoelectric conversion elements when viewed in an oblique 45 degree direction in the row direction X and the column direction Y is an RGB Bayer array, and the row direction X In addition, a color filter is provided so that the 2 × 2 arrangement of the first photoelectric conversion elements when viewed in an oblique 45 ° direction in the column direction Y is an rgb Bayer arrangement.

  In the present embodiment, the photoelectric conversion element 51B and the photoelectric conversion element 51b adjacent to the lower side of the photoelectric conversion element 51B in FIG. 7 are paired, and the photoelectric conversion element 51G and the photoelectric conversion element 51G are positioned on the lower side of FIG. The adjacent photoelectric conversion element 51g makes a pair, and the photoelectric conversion element 51R and the photoelectric conversion element 51r adjacent to the lower side of the photoelectric conversion element 51R in FIG. 7 form a pair.

  The photoelectric conversion elements of the first photoelectric conversion element and the second photoelectric conversion element are arranged so that the photoelectric conversion elements that detect the same color component are adjacent to each other. That is, the photoelectric conversion element 51R is adjacent to the photoelectric conversion element 51r in the column direction Y, the photoelectric conversion element 51G is adjacent to the photoelectric conversion element 51g in the column direction Y, and the photoelectric conversion element 51B is adjacent to the photoelectric conversion element 51b in the column direction Y. Adjacent.

  As shown in FIG. 7, the imaging element in which the photoelectric conversion elements are arranged can also correct the defective pixel in the same procedure as in the first embodiment.

FIG. 8 is a schematic diagram showing a defective pixel and a photoelectric conversion element of the same color component adjacent to the defective pixel in the photoelectric conversion element array of FIG.
As shown in FIG. 8, when the photoelectric conversion element indicated by diagonal lines is a defective pixel, a pair of photoelectric conversion elements adjacent to the defective pixel (photoelectric conversion element for detecting g light circled in FIG. 8) ) Is a defect, and when the photoelectric conversion element for detecting the adjacent g light is not a defective pixel, the pixel signal detected by the photoelectric conversion element for detecting the g light is used as the pixel of the defective pixel. The correction processing is performed by using the signal as it is or when the first photoelectric conversion element and the second photoelectric conversion element have different light reception sensitivities, only by multiplication of sensitivity coefficients corresponding to the light reception sensitivities.

FIG. 9 is a schematic diagram illustrating a defective pixel and a photoelectric conversion element having the same color component adjacent to the defective pixel in the arrangement of the photoelectric conversion elements in FIG. 7.
As shown in FIG. 9, in the case where the photoelectric conversion element indicated by hatching is a defective pixel, a pair of photoelectric conversion elements adjacent to the defective pixel (photoelectric conversion element for detecting G light circled in FIG. 9) ) Is a defect, and when the photoelectric conversion element for detecting the adjacent G light is not a defective pixel, the pixel signal detected by the photoelectric conversion element for detecting the G light is used as the pixel of the defective pixel. Correction processing is performed as a signal.

  On the other hand, as shown in FIG. 10, when both the photoelectric conversion element that detects G light indicated by the oblique lines and the photoelectric conversion element that detects g light adjacent to the photoelectric conversion element that detects the G light are defective pixels. Is the closest photoelectric conversion element arranged around the defective pixel and detects the same G light (a photoelectric conversion element that detects G light circled in FIG. 10). The defective pixel is corrected using the pixel signal. In this embodiment, the case where the photoelectric conversion element that detects G light or g light is a defective pixel has been described as an example. However, when the photoelectric conversion element that detects R light or r light is a defective pixel, The same correction can be made when the photoelectric conversion element that detects b light is a defective pixel.

It is a figure which shows schematic structure of the digital camera which is an example of the imaging device which performs the defective pixel correction method of this invention. It is the plane schematic diagram which showed one structural example of the solid-state image sensor 5 shown in FIG. It is a flowchart which shows the procedure of the defective pixel correction method. It is a schematic diagram which shows the case where the photoelectric conversion element which detects G light of a 1st photoelectric conversion element is a defective pixel. It is a schematic diagram which shows the case where the photoelectric conversion element which detects the g light of a 2nd photoelectric conversion element is a defective pixel. It is a schematic diagram which shows the case where both the photoelectric conversion element which detects G light, and the photoelectric conversion element which detects g light adjacent to the photoelectric conversion element which detects this G light are defective pixels. It is a figure which shows typically the other example of the arrangement | sequence of a photoelectric conversion element. FIG. 8 is a schematic diagram illustrating a defective pixel and a photoelectric conversion element having the same color component adjacent to the defective pixel in the arrangement of the photoelectric conversion elements in FIG. 7. FIG. 8 is a schematic diagram illustrating a defective pixel and a photoelectric conversion element having the same color component adjacent to the defective pixel in the arrangement of the photoelectric conversion elements in FIG. 7. It is a schematic diagram which shows the case where both the photoelectric conversion element which detects G light, and the photoelectric conversion element which detects g light adjacent to the photoelectric conversion element which detects this G light are defective pixels.

Explanation of symbols

5 Image sensor 51R, 51G, 51B 1st photoelectric conversion element 51r, 51g, 51b 2nd photoelectric conversion element

Claims (5)

A plurality of photoelectric conversion elements for detecting light of a color component necessary for generating color image data are provided, and the plurality of photoelectric conversion elements are a plurality of first photoelectric conversion elements and a plurality of second photoelectric conversion elements. The plurality of first photoelectric conversion elements and the plurality of second photoelectric conversion elements are arranged in the same arrangement, and the photoelectric conversion elements that detect the same color component are arranged adjacent to each other. A defective pixel correction method for an image sensor,
When one of the first photoelectric conversion element and the second photoelectric conversion element is a defective pixel, the other photoelectric conversion element is close to the defective pixel and has the same color component. The pixel signal detected by the photoelectric conversion element to be detected is acquired and the pixel signal is used as it is as the pixel signal of the defective pixel, or the light receiving sensitivity of the first photoelectric conversion element and the second photoelectric conversion element is A defective pixel correction method in which correction processing is performed only by multiplication of a sensitivity coefficient corresponding to the light receiving sensitivity if different.   When the photoelectric conversion element that is close to the defective pixel and detects the same color component is defective, the defective pixel is included in the first photoelectric conversion element or the second photoelectric conversion element. 2. The defect according to claim 1, wherein a pixel signal is obtained from a photoelectric conversion element closest to the defective pixel and having the same color component, and the pixel signal of the defective pixel is calculated based on the pixel signal. Pixel correction method.   The first photoelectric conversion element and the second photoelectric conversion element are respectively arranged in a square lattice form in a row direction and a column direction, and the first photoelectric conversion element and the second photoelectric conversion element are arranged at about an arrangement pitch. The defective pixel correction method according to claim 1, wherein the defective pixel correction method is arranged at a position shifted by ½ in the row direction and the column direction.   The first photoelectric conversion element and the second photoelectric conversion element are arranged in a square lattice so as to be inclined with respect to the row direction and the column direction, respectively, and the row direction and the column of the first photoelectric conversion element The defective pixel correction method according to claim 1, wherein each second photoelectric conversion element is disposed between the directions. A plurality of photoelectric conversion elements for detecting light of a color component necessary for generating color image data are provided, and the plurality of photoelectric conversion elements are a plurality of first photoelectric conversion elements and a plurality of second photoelectric conversion elements. The plurality of first photoelectric conversion elements and the plurality of second photoelectric conversion elements are arranged in the same arrangement, and the photoelectric conversion elements that detect the same color component are arranged adjacent to each other. An image pickup apparatus including an image pickup device,
When one of the first photoelectric conversion element and the second photoelectric conversion element is a defective pixel, the other photoelectric conversion element is close to the defective pixel and has the same color component. An imaging apparatus comprising defective pixel correction means for acquiring a pixel signal detected by a photoelectric conversion element to be detected and performing correction processing using the pixel signal as it is as a pixel signal of the defective pixel.

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