JP2006108950A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus for correcting pixels of a white spot by taking into account an operating temperature and an exposure time of a solid-state image sensor and correcting the white spot without degrading the resolution of an image, and to provide a correction method of a pixel signal. <P>SOLUTION: A white spot detection correction circuit 6 detects the white spot on the basis of the pixel signal outputted from the solid-state image sensor 3 by utilizing a sensor resulting dark current that is a difference between a pixel signal of a light shield pixel and a pixel signal of a vertical transfer register, calculates the sensor resulting dark current in a light shield state, calculates a ratio of the pixel signal of the white spot to the sensor resulting dark current and stores an address of the white spot and the ratio to a white spot ROM 9 in cross-reference with each other. The white spot detection correction circuit 6 multiplies the stored ratio with the sensor resulting dark current of the solid-state image sensor 3 in the operating state to calculate a defective component of the pixel signal of the white spot, and eliminates the defective component of the pixel signal of the white spot by subtracting the defective component from the pixel signal of the white spot to correct the pixel signal of the white spot. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image pickup apparatus that corrects a pixel signal of a defective pixel of a solid-state image sensor and a pixel signal correction method.

  In an image taken by an imaging device such as a video camera or a digital camera, various image defects due to the solid-state imaging device appear. An image defect includes fixed pattern noise (FPN) appearing at the same position in an image, and a well-known fixed pattern noise includes a white spot (white scratch). A white point indicates that when a semiconductor constituting a pixel (also referred to as a photoelectric conversion element or a sensor) is contaminated by metal ions or the crystallinity of the semiconductor is damaged, dark current is generated and This occurs when the signal output increases. White spots are recognized as bright spots such as white, red, and blue in the image.

In a conventional imaging device, a white point is detected and its address and pixel value are stored in advance, and the stored pixel value is subtracted from the pixel value of the white point output from the solid-state image sensor, or the white point The address is stored in advance, and the white point is removed by replacing the pixel value of the white point with the average value of the pixel values of surrounding pixels.
Further, the dark current that generates a white spot depends on the temperature, and increases as the temperature increases. For this reason, in the conventional imaging device, the operating temperature of the solid-state imaging device is detected, and white point pixels are corrected according to the detected temperature. As a method for detecting the operating temperature of the solid-state imaging device, for example, it is obtained by calculation based on pixel signals output from the solid-state imaging device (see, for example, Patent Documents 1 and 2).
Japanese Patent Laid-Open No. 9-23358 JP 11-317516 A

However, in the conventional imaging device, although white point pixels are corrected according to the temperature of the solid-state imaging device, no consideration is given to the exposure time of the solid-state imaging device. The dark current that generates a white spot depends on the exposure time and increases with an increase in the exposure time. For this reason, a correction method for correcting white point pixels in accordance with a change in exposure time of the solid-state imaging device is desired.
Further, in the conventional imaging device, when the pixel value of the white point pixel is replaced based on the pixel value of the surrounding pixels, the resolution of the image is lowered, and in particular, the edge portion is lost, resulting in a blurred image. There was a problem such as.
In the manufacturing process of the solid-state imaging device, although the reduction of foreign matters is attempted, it is difficult to remove the white spots of the solid-state imaging device as described above.

  The present invention has been made in view of such circumstances, and an object of the present invention is to correct white point pixels in consideration of the operating temperature and exposure time of the solid-state imaging device, and without reducing the image resolution. An object of the present invention is to provide an imaging device for correcting a white point and a method for correcting a pixel signal.

In order to achieve the above object, a first image pickup apparatus of the present invention includes a solid-state image pickup device that outputs a pixel signal, and correction means that corrects the pixel signal output from the solid-state image pickup device. Are arranged around a plurality of effective pixels so as to form a matrix together with the plurality of effective pixels, and a plurality of effective pixels arranged in a matrix for converting incident light into signal charges and outputting them as pixel signals. A plurality of light-shielding pixels covered with a light-shielding film, at least one pixel transfer unit of an effective pixel transfer unit that extracts pixel signals of the plurality of effective pixels, and a light-shielding pixel transfer unit that extracts image signals of the plurality of light-shielding pixels A plurality of effective / light-shielded pixel vertical transfer registers that extract pixel signals for each column of the plurality of effective pixels and the plurality of light-shielded pixels and transfer them in the vertical direction. A light-shielding pixel portion, one or a plurality of invalid pixel vertical transfer registers arranged in a column or matrix around the effective / light-shielding pixel portion and transferring pixel signals having a pixel value of 0 in the vertical direction; And a horizontal transfer register that transfers pixel signals transferred by the one or more invalid pixel vertical transfer registers in a horizontal direction, wherein the correction means When the image sensor is operated in a light-shielded state, the solid-state image sensor is transferred by the invalid pixel vertical transfer register from pixel signals of the plurality of light-shielded pixels extracted by the light-shielded pixel transfer unit and output by the solid-state image sensor. When the solid-state imaging device is operated in a light-shielded state using a sensor-induced dark current obtained by subtracting the pixel signal output by the solid-state imaging device A defect that stores the address of the defective pixel of the solid-state imaging device detected based on the pixel signal output by the pixel signal and the ratio of the pixel signal of the defective pixel corresponding to the address and the dark current caused by the sensor in association with each other Pixel signals that are transferred by the invalid pixel vertical transfer register from the pixel signals of the plurality of light-shielded pixels output by the solid-state image sensor and output by the pixel storage means and the light-shielded pixel transfer unit, and output by the solid-state image sensor The sensor-derived dark current calculation means for calculating the sensor-induced dark current and the address of the defective pixel stored in the defective pixel storage means and the corresponding ratio are read out and calculated by the sensor-derived dark current calculation means. A defect component calculating means for multiplying the sensor-induced dark current by the ratio and calculating a defect component of a pixel signal of the defective pixel; The defective pixel output by the solid-state imaging device is obtained by subtracting the defective component of the pixel signal of the corresponding defective pixel calculated by the defective component calculating means from the pixel signal of the defective pixel at the address output by the solid-state imaging device. And defect component removing means for removing the defect component from the pixel signal.
The second imaging device of the present invention includes a solid-state imaging device that outputs a pixel signal, and a correction unit that corrects the pixel signal output by the solid-state imaging device. A plurality of effective pixels arranged in a matrix for converting light into signal charges and outputting as pixel signals, and arranged around the effective pixels so as to form a matrix together with the plurality of effective pixels, A plurality of covered light-shielding pixels, an effective pixel transfer unit that extracts pixel signals of the plurality of effective pixels, and a light-shielding pixel transfer unit that extracts image signals of the plurality of light-shielded pixels, respectively, An effective / light-shielding pixel section having a plurality of effective / light-shielding pixel vertical transfer registers that extract pixel signals for each of the plurality of effective pixels and the plurality of light-shielding pixels and transfer them in the vertical direction; One or a plurality of invalid pixel vertical transfer registers that are arranged in a column or matrix around the valid / light-shielded pixel portion and transfer a pixel signal having a pixel value of 0 in the vertical direction, and the plurality of valid / light-shielded pixels vertical A solid-state image pickup device having a transfer register and a horizontal transfer register for horizontally transferring a pixel signal transferred by the one or more invalid pixel vertical transfer registers, wherein the correcting means blocks the solid-state image pickup device in a light-shielding state. And when the solid-state image sensor is operated in a light-shielded state, the light-shielding unit detects the defective pixel of the solid-state image sensor based on a pixel signal output from the solid-state image sensor. Transferred from the pixel signals of the plurality of light-shielded pixels extracted by the pixel transfer unit and output from the solid-state imaging device by the invalid pixel vertical transfer register. A first sensor-induced dark current calculation unit that calculates a sensor-induced dark current by subtracting a pixel signal output from the solid-state imaging device, a pixel signal of the defective pixel detected by the defective pixel detection unit, and the first A ratio calculation means for calculating a ratio with the sensor-induced dark current calculated by the sensor-derived dark current calculation means, an address of the defective pixel detected by the defective pixel detection means, and the address calculated by the ratio calculation means And defective pixel storage means for storing the ratio of defective pixels corresponding to the pixel, and the invalid pixel vertical transfer from the pixel signals of the plurality of light-shielded pixels extracted by the light-shielded pixel transfer unit and output by the solid-state imaging device A second sensor-induced dark that calculates the sensor-induced dark current by subtracting the pixel signal transferred by the register and output by the solid-state imaging device Read the current calculation means, the address of the defective pixel stored in the defective pixel storage means and the corresponding ratio, multiply the sensor-induced dark current calculated by the second sensor-derived dark current calculation means by the ratio, Defect component calculation means for calculating a defect component of the pixel signal of the defective pixel, and a corresponding defective pixel pixel calculated by the defect component calculation means from the pixel signal of the defective pixel at the address output by the solid-state imaging device And a defect component removing unit that subtracts the defect component of the signal and removes the defect component from the pixel signal of the defective pixel output by the solid-state imaging device.
The first pixel signal correcting method according to the present invention includes a plurality of effective pixels arranged in a matrix that converts incident light into signal charges and outputs the signal as a pixel signal, and a matrix together with the plurality of effective pixels. A plurality of light-shielded pixels arranged around the plurality of effective pixels and covered with a light-shielding film, an effective pixel transfer unit that extracts pixel signals of the plurality of effective pixels, and image signals of the plurality of light-shielded pixels A plurality of effective / light-shielded pixels that each have at least one pixel-transfer portion of a light-shielded pixel transfer portion that takes out the pixel signals, extracts pixel signals for each of the plurality of effective pixels and the plurality of light-shielded pixels, and transfers them in the vertical direction. An effective / light-shielding pixel portion having a transfer register, and one or a plurality of non-transparent pixels that are arranged in a column or matrix around the effective / light-shielding pixel portion and transfer pixel signals having a pixel value of 0 in the vertical direction. A solid-state imaging device comprising: a pixel vertical transfer register; and a horizontal transfer register for horizontally transferring pixel signals transferred by the plurality of valid / light-shielded pixel vertical transfer registers and the one or more invalid pixel vertical transfer registers A pixel signal correction method for correcting an output pixel signal, wherein when the solid-state image sensor is operated in a light-shielded state, a defective pixel of the solid-state image sensor based on a pixel signal output by the solid-state image sensor And detecting the defective pixel from the pixel signals of the plurality of light-shielded pixels extracted by the light-shielded pixel transfer unit and output by the solid-state image sensor when the solid-state image sensor is operated in a light-shielded state. The pixel signal transferred by the vertical transfer register and output by the solid-state image sensor is subtracted to display the sensor-induced dark current. And calculating a ratio of the pixel signal of the defective pixel detected in the defective pixel detection step to the sensor-induced dark current calculated in the first sensor-derived dark current calculation step. A defective pixel storing step for storing the ratio of the defective pixel detected in the defective pixel detecting step and the ratio of the defective pixel corresponding to the address calculated in the ratio calculating step in association with each other; The sensor signal is derived by subtracting the pixel signal transferred by the invalid pixel vertical transfer register and output by the solid-state image sensor from the pixel signals of the plurality of light-shielded pixels output by the light-shielded pixel transfer unit and output by the solid-state image sensor. Second sensor-derived dark current calculation step for calculating dark current, and defects stored in the defective pixel storage step Defect component calculation that reads the pixel address and the corresponding ratio, multiplies the sensor-induced dark current calculated in the second sensor-derived dark current calculation step by the ratio, and calculates the defect component of the pixel signal of the defective pixel And subtracting the defect component of the pixel signal of the corresponding defective pixel calculated in the defect component calculation step from the pixel signal of the defective pixel at the address output by the solid-state imaging device, and outputting by the solid-state imaging device And a defect component removing step of removing the defect component from the pixel signal of the defective pixel.
In addition, a third imaging device of the present invention includes a solid-state imaging device that outputs a pixel signal and correction means that corrects the pixel signal output by the solid-state imaging device, and the solid-state imaging device is incident A plurality of effective pixels arranged in a matrix for converting light into signal charges and outputting as pixel signals, and arranged around the effective pixels so as to form a matrix together with the plurality of effective pixels, A plurality of covered light-shielding pixels, an effective pixel transfer unit that extracts pixel signals of the plurality of effective pixels, and a light-shielding pixel transfer unit that extracts image signals of the plurality of light-shielded pixels, respectively, An effective / light-shielding pixel section having a plurality of effective / light-shielding pixel vertical transfer registers that extract pixel signals for each of the plurality of effective pixels and the plurality of light-shielding pixels and transfer them in the vertical direction; One or a plurality of invalid pixel verticals arranged in a row or matrix around the valid / light-shielded pixel portion and transferring a pixel signal having a pixel value of 0 in the vertical direction to the valid / light-shielded pixel vertical transfer register An image pickup apparatus comprising: a transfer register; and a horizontal transfer register that horizontally transfers pixel signals transferred by the plurality of effective / light-shielded pixel vertical transfer registers, wherein the correction unit blocks the solid-state image sensor in a light-shielded state. Pixels transferred by the invalid pixel vertical transfer register from the pixel signals of the plurality of light-shielded pixels output by the light-shielded pixel transfer unit and output by the solid-state image sensor when operated by the solid-state image sensor Pixels output by the solid-state image sensor when the solid-state image sensor is operated in a light-shielded state using a sensor-induced dark current obtained by subtracting the signal Defective pixel storage means for storing the address of the defective pixel of the solid-state imaging device detected based on the number, and the ratio of the pixel signal of the defective pixel corresponding to the address and the sensor-induced dark current in association with each other; A pixel signal transferred by the invalid pixel vertical transfer register and output from the solid-state image sensor and subtracted from a pixel signal of the plurality of light-shielded pixels output by the solid-state image sensor taken out by the light-shielded pixel transfer unit; A sensor-induced dark current calculation means for calculating the induced dark current and an address and a corresponding ratio of the defective pixel stored in the defective pixel storage means are read out, and the sensor-derived dark current calculated by the sensor-derived dark current calculation means is obtained. Defect component calculation means for multiplying the ratio and calculating a defect component of the pixel signal of the defective pixel, and the solid-state imaging device. The defect component of the pixel signal of the corresponding defective pixel calculated by the defect component calculation means is subtracted from the pixel signal of the defective pixel at the address that has been input, and the defect signal is output from the pixel signal of the defective pixel output by the solid-state imaging device. And a defect component removing means for removing the component.
In addition, a fourth imaging device of the present invention includes a solid-state imaging device that outputs a pixel signal and correction means that corrects the pixel signal output by the solid-state imaging device, and the solid-state imaging device is incident A plurality of effective pixels arranged in a matrix for converting light into signal charges and outputting as pixel signals, and arranged around the effective pixels so as to form a matrix together with the plurality of effective pixels, A plurality of covered light-shielding pixels, an effective pixel transfer unit that extracts pixel signals of the plurality of effective pixels, and a light-shielding pixel transfer unit that extracts image signals of the plurality of light-shielded pixels, respectively, An effective / light-shielding pixel section having a plurality of effective / light-shielding pixel vertical transfer registers that extract pixel signals for each of the plurality of effective pixels and the plurality of light-shielding pixels and transfer them in the vertical direction; One or a plurality of invalid pixel verticals arranged in a row or matrix around the valid / light-shielded pixel portion and transferring a pixel signal having a pixel value of 0 in the vertical direction to the valid / light-shielded pixel vertical transfer register An image pickup apparatus comprising: a transfer register; and a horizontal transfer register that horizontally transfers pixel signals transferred by the plurality of effective / light-shielded pixel vertical transfer registers, wherein the correction unit blocks the solid-state image sensor in a light-shielded state. And when the solid-state image sensor is operated in a light-shielded state, the light-shielding unit detects the defective pixel of the solid-state image sensor based on a pixel signal output from the solid-state image sensor. The pixel signals of the plurality of light-shielded pixels extracted by the pixel transfer unit and output by the solid-state imaging device are transferred by the invalid pixel vertical transfer register and the fixed pixels are output. A first sensor-induced dark current calculation unit that calculates a sensor-induced dark current by subtracting a pixel signal output from the image sensor, a pixel signal of the defective pixel detected by the defective pixel detection unit, and the first sensor Corresponding to the ratio calculation means for calculating the ratio of the sensor-derived dark current calculated by the caused dark current calculation means, the address of the defective pixel detected by the defective pixel detection means, and the address calculated by the ratio calculation means Defective pixel storage means for storing the ratio of defective pixels to be associated with each other, and the invalid pixel vertical transfer register from the pixel signals of the plurality of light-shielded pixels extracted by the light-shielded pixel transfer unit and output by the solid-state imaging device. Second sensor-derived dark current calculation for subtracting the pixel signal transferred and output by the solid-state imaging device to calculate the sensor-induced dark current And a defective pixel address and a corresponding ratio stored in the defective pixel storage means, multiply the sensor-induced dark current calculated by the second sensor-derived dark current calculation means by the ratio, and A defect component calculation means for calculating a defect component of the pixel signal of the pixel, and a pixel signal of the corresponding defective pixel calculated by the defect component calculation means from the pixel signal of the defective pixel at the address output by the solid-state imaging device. Defect component removal means for subtracting the defect component and removing the defect component from the pixel signal of the defective pixel output by the solid-state imaging device.
The second pixel signal correction method according to the present invention includes a plurality of effective pixels arranged in a matrix that converts incident light into signal charges and outputs them as pixel signals, and a matrix together with the plurality of effective pixels. A plurality of light-shielded pixels arranged around the plurality of effective pixels and covered with a light-shielding film, an effective pixel transfer unit that extracts pixel signals of the plurality of effective pixels, and image signals of the plurality of light-shielded pixels A plurality of effective / light-shielded pixels that each have at least one pixel-transfer portion of a light-shielded pixel transfer portion that takes out the pixel signals, extracts pixel signals for each of the plurality of effective pixels and the plurality of light-shielded pixels, and transfers them in the vertical direction. An effective / light-shielding pixel portion having a transfer register; and a pixel signal having a pixel value of 0 arranged in a row or matrix around the effective / light-shielding pixel portion in a vertical direction to transfer the effective / light-shielding image portion Output by an imaging device comprising one or more invalid pixel vertical transfer registers for transferring to a vertical transfer register and a horizontal transfer register for transferring pixel signals transferred by the plurality of valid / light-shielded pixel vertical transfer registers in the horizontal direction A pixel signal correcting method for correcting a pixel signal to be corrected, wherein when the solid-state image sensor is operated in a light-shielded state, defective pixels of the solid-state image sensor are detected based on the pixel signal output by the solid-state image sensor. Detecting defective pixels to be detected, and when the solid-state image sensor is operated in a light-shielded state, the invalid pixel vertical is extracted from the pixel signals of the plurality of light-shielded pixels extracted by the light-shielded pixel transfer unit and output by the solid-state image sensor. Subtracting the pixel signal transferred by the transfer register and output by the solid-state imaging device, the sensor-induced dark current is calculated. Sensor-derived dark current calculation step, and ratio calculation for calculating a ratio between the pixel signal of the defective pixel detected in the defective pixel detection step and the sensor-induced dark current calculated in the first sensor-derived dark current calculation step A defective pixel storing step for storing the step, the address of the defective pixel detected in the defective pixel detecting step and the ratio of the defective pixel corresponding to the address calculated in the ratio calculating step in association with each other; and Subtracting the pixel signal transferred by the invalid pixel vertical transfer register and output from the solid-state image sensor from the pixel signals of the plurality of light-shielded pixels output by the transfer unit and output by the solid-state image sensor, and the sensor-induced dark current is subtracted. A second sensor-induced dark current calculation step to be calculated, and the defective pixel stored in the defective pixel storage step. A defect component calculating step of reading a dress and a corresponding ratio, multiplying the sensor-induced dark current calculated in the second sensor-derived dark current calculating step by the ratio, and calculating a defect component of a pixel signal of the defective pixel; The defect component output from the solid-state imaging device is obtained by subtracting the defect component of the pixel signal of the corresponding defective pixel calculated in the defect component calculation step from the pixel signal of the defective pixel at the address output by the solid-state imaging device. A defect component removing step of removing a defect component from the pixel signal of the pixel.

According to the first imaging device of the present invention, first, the pixels of the plurality of light-shielded pixels that are taken out by the light-shielded pixel transfer unit and output by the solid-state image sensor when the solid-state image sensor is operated in a light-shielded state. When the solid-state imaging device is operated in a light-shielded state by the defective pixel storage means using a sensor-induced dark current obtained by subtracting a pixel signal transferred from the signal by the invalid pixel vertical transfer register and output by the solid-state imaging device Corresponding to the address of the defective pixel of the solid-state imaging device detected based on the pixel signal output by the solid-state imaging device, and the ratio of the pixel signal of the defective pixel corresponding to the address and the sensor-induced dark current Add and remember. Next, the invalid pixel vertical transfer register transfers the pixel signals of the plurality of light-shielded pixels outputted by the light-shielded pixel transfer unit and output by the solid-state image sensor by the sensor-induced dark current calculation means, and is transmitted by the solid-state image sensor. The sensor-generated dark current is calculated by subtracting the output pixel signal. Next, the address of the defective pixel stored in the defective pixel storage unit and the corresponding ratio are read by the defective component calculation unit, the sensor-induced dark current calculated by the sensor-derived dark current calculation unit is multiplied by the ratio, A defect component of a pixel signal of the defective pixel is calculated. Next, the defect component of the pixel signal of the corresponding defective pixel calculated by the defect component calculation unit is subtracted from the pixel signal of the defective pixel at the address output by the solid-state imaging device by the defect component removal unit, and the solid The defective component is removed from the pixel signal of the defective pixel output by the imaging device.
For this reason, the pixel signal of the defective pixel of the solid-state image sensor obtained in the light-shielded state and the sensor origin are obtained by using the sensor-induced dark current that is the difference between the pixel signal of the plurality of light-shielded pixels and the pixel signal of the invalid pixel vertical transfer register By multiplying the dark current ratio of the solid-state image sensor in the active state by the dark current caused by the sensor, the defect component included in the pixel signal of the defective pixel is calculated, and the calculated defect component is subtracted from the pixel signal of the defective pixel. It is possible to remove a defective component included in a pixel signal of a defective pixel.
Therefore, since the dark current itself caused by the sensor of the solid-state imaging device depending on the temperature and the exposure time can be detected and the defective pixel can be corrected, the defective pixel can be corrected with high accuracy. Further, since the address of the defective pixel and the ratio thereof are stored in association with each other, the memory capacity can be reduced. There is no need for a calculation table in which the temperature and the correction amount are associated with each other. In addition, since it is not necessary to replace defective pixels based on the pixel values of the peripheral pixels, the edge portion can be corrected correctly and a sharp image can be obtained without reducing the image resolution.
According to the second imaging device of the present invention, when the solid-state imaging device is operated in a light-shielded state, the solid-state imaging device is operated based on a pixel signal output from the solid-state imaging device by a defective pixel detection unit. A defective pixel is detected and transferred by the invalid pixel vertical transfer register from the pixel signals of the plurality of light-shielded pixels output by the solid-state image sensor and extracted by the light-shielded pixel transfer unit by the first sensor-derived dark current calculation means. Then, the pixel signal output from the solid-state image sensor is subtracted to calculate a sensor-induced dark current. Next, a ratio between the pixel signal of the defective pixel detected by the defective pixel detection unit and the sensor-induced dark current calculated by the first sensor-derived dark current calculation unit is calculated by the ratio calculation unit. Next, the defective pixel storage means stores the defective pixel address detected by the defective pixel detection means in association with the defective pixel ratio corresponding to the address calculated by the ratio calculation means. Then, the solid-state image sensor is transferred by the invalid pixel vertical transfer register from the pixel signals of the plurality of light-shielded pixels output by the solid-state image sensor and extracted by the light-shielded pixel transfer unit by the second sensor-induced dark current calculation means. The pixel signal output by is subtracted to calculate the sensor-induced dark current. Next, the defect component calculation means reads the defective pixel address and the corresponding ratio stored in the defective pixel storage means, and sets the ratio to the sensor-induced dark current calculated by the second sensor-derived dark current calculation means. Multiply and calculate the defective component of the pixel signal of the defective pixel. Next, the defect component of the pixel signal of the corresponding defective pixel calculated by the defect component calculation unit is subtracted from the pixel signal of the defective pixel at the address output by the solid-state imaging device by the defect component removal unit, and the solid The defective component is removed from the pixel signal of the defective pixel output by the imaging device.
Therefore, the sensor-induced dark current, which is the difference between the pixel signals of the plurality of light-shielded pixels and the pixel signal of the invalid pixel vertical transfer register, is used to detect a defective pixel of the solid-state imaging device in the light-shielded state and The dark current is calculated, the ratio between the pixel signal of the defective pixel and the sensor-induced dark current is calculated, and the calculated ratio is stored in association with the corresponding defective pixel. Then, the sensor-induced dark current of the solid-state imaging device in the operating state is calculated, the defect ratio included in the pixel signal of the defective pixel is calculated by multiplying the stored ratio, and the calculated defect component is calculated as the pixel signal of the defective pixel. The defect component included in the pixel signal of the defective pixel can be removed by subtracting from.
Therefore, it has the same effect as the first imaging device.
In addition, the correction means includes the defective pixel detection means, the first sensor-induced dark current calculation means, and the ratio calculation means, and the address of the defective pixel and its ratio (the pixel signal of the defective pixel and the sensor-induced dark current The ratio is stored in association with the defective pixel storage means.
Therefore, it is not necessary to detect defective pixels by a dedicated device and obtain the defective pixel addresses and their ratios.
According to the first pixel signal correction method of the present invention, when the solid-state image sensor is operated in a light-shielded state in the defective pixel detection step, the solid-state image signal is output based on the pixel signal output from the solid-state image sensor. The plurality of pixels extracted by the light-shielded pixel transfer unit and output by the solid-state image sensor when the defective pixels of the image sensor are detected and the solid-state image sensor is operated in a light-shielded state in the first sensor-induced dark current calculation step The pixel signal transferred by the invalid pixel vertical transfer register and output from the solid-state imaging device is subtracted from the pixel signal of the light-shielded pixel, and the sensor-induced dark current is calculated and detected in the defective pixel detection step in the ratio calculation step. Calculating a ratio between the pixel signal of the defective pixel and the sensor-induced dark current calculated in the first sensor-derived dark current calculating step, and storing the defective pixel The address of the detected defective pixel in the defective pixel detection step said ratio calculating step in association with the ratio of defective pixels corresponding to the calculated said address stored in step. Then, in the second sensor-induced dark current calculation step, the solid-state image sensor is transferred by the invalid pixel vertical transfer register from the pixel signals of the plurality of light-shielded pixels output by the light-shielded pixel transfer unit and output by the solid-state image sensor. Subtracting the pixel signal output from the sensor, calculating a sensor-induced dark current, reading the defective pixel address and the corresponding ratio stored in the defective pixel storing step in the defect component calculating step, and The sensor-induced dark current calculated in the current calculation step is multiplied by the ratio, the defect component of the pixel signal of the defective pixel is calculated, and the defective pixel of the address output by the solid-state imaging device in the defect component removal step is calculated. Subtract the defect component of the pixel signal of the corresponding defective pixel calculated in the defect component calculation step from the pixel signal, Serial removing defective component from the pixel signal of the defective pixel output by the solid-state imaging device.
Therefore, the sensor-induced dark current, which is the difference between the pixel signals of a plurality of light-shielded pixels and the pixel signal of the invalid pixel vertical transfer register, is used to detect a defective pixel of the solid-state imaging device in a light-shielded state and The resulting dark current is calculated, the ratio between the pixel signal of the defective pixel and the sensor-induced dark current is calculated, and the calculated ratio is stored in association with the corresponding defective pixel. Then, the sensor-induced dark current of the solid-state imaging device in the operating state is calculated, the defect ratio included in the pixel signal of the defective pixel is calculated by multiplying the stored ratio, and the calculated defect component is calculated as the pixel signal of the defective pixel. The defect component included in the pixel signal of the defective pixel can be removed by subtracting from.
Therefore, it has the same effect as the second imaging device.
Further, according to the third imaging device of the present invention, a plurality of effective pixels arranged in a matrix for converting incident light into signal charges and outputting them as pixel signals, and a matrix together with the plurality of effective pixels A plurality of light-shielded pixels arranged around the plurality of effective pixels and covered with a light-shielding film, an effective pixel transfer unit that extracts pixel signals of the plurality of effective pixels, and image signals of the plurality of light-shielded pixels A plurality of effective / light-shielded pixel vertical transfers, each having at least one pixel transfer part of the light-shielded pixel transfer part to be taken out, extracting pixel signals for each of the plurality of effective pixels and the plurality of light-shielded pixels and transferring them in the vertical direction An effective / light-shielding pixel portion having a register and a pixel signal having a pixel value of 0 arranged in a row or matrix around the effective / light-shielding pixel portion in the vertical direction to transfer the effective / light-shielding pixel portion For a solid-state imaging device having one or more invalid pixel vertical transfer registers for transferring to a transfer register and a horizontal transfer register for transferring pixel signals transferred by the plurality of valid / light-shielded pixel vertical transfer registers in a horizontal direction, Correction of defective pixels is performed in the same manner as in the first imaging device.
Therefore, it has the same effect as the first imaging device.
Further, according to the fourth imaging device of the present invention, a plurality of effective pixels arranged in a matrix for converting incident light into signal charges and outputting them as pixel signals, and a matrix together with the plurality of effective pixels A plurality of light-shielded pixels arranged around the plurality of effective pixels and covered with a light-shielding film, an effective pixel transfer unit that extracts pixel signals of the plurality of effective pixels, and image signals of the plurality of light-shielded pixels A plurality of effective / light-shielded pixel vertical transfers, each having at least one pixel transfer part of the light-shielded pixel transfer part to be taken out, extracting pixel signals for each of the plurality of effective pixels and the plurality of light-shielded pixels and transferring them in the vertical direction An effective / light-shielding pixel portion having a register and a pixel signal having a pixel value of 0 arranged in a row or matrix around the effective / light-shielding pixel portion in the vertical direction to transfer the effective / light-shielding pixel portion For a solid-state imaging device having one or more invalid pixel vertical transfer registers for transferring to a transfer register and a horizontal transfer register for transferring pixel signals transferred by the plurality of valid / light-shielded pixel vertical transfer registers in a horizontal direction, Correction of defective pixels is performed in the same manner as in the second imaging device.
Therefore, it has the same effect as the second imaging device.
According to the second pixel signal correction method of the present invention, together with the plurality of effective pixels arranged in a matrix that converts incident light into a signal charge and outputs it as a pixel signal, the plurality of effective pixels A plurality of light-shielding pixels arranged around the plurality of effective pixels so as to form a matrix and covered with a light-shielding film; an effective pixel transfer unit that extracts pixel signals of the plurality of effective pixels; and the plurality of light-shielding pixels A plurality of effective / light-shielding units each having at least one pixel-transfer unit of a light-shielding pixel transfer unit for extracting an image signal, extracting pixel signals for each of the plurality of effective pixels and the plurality of light-shielding pixels, and transferring them in the vertical direction An effective / light-shielding pixel portion having a pixel vertical transfer register; and a pixel signal having a pixel value of 0 arranged in a row or matrix around the effective / light-shielding pixel portion in the vertical direction to transmit the effective / light-shielding pixel portion. A solid-state imaging device having one or more invalid pixel vertical transfer registers for transferring to an optical pixel vertical transfer register and a horizontal transfer register for transferring pixel signals transferred by the plurality of valid / light-shielded pixel vertical transfer registers in a horizontal direction On the other hand, the defective pixel is corrected in the same manner as the above-described pixel signal correction method.
Therefore, it has the same effect as the first pixel signal correction method.

  In order to achieve the above object, the defective pixel of the solid-state imaging device is detected in the light-shielded state, the sensor-induced dark current in the light-shielded state is calculated, and the ratio between the pixel signal of the defective pixel and the sensor-induced dark current is calculated and calculated. The ratio is stored in association with the corresponding defective pixel. Then, the defect ratio included in the pixel signal of the defective pixel is calculated by multiplying the stored ratio by the sensor-induced dark current of the corresponding defective pixel of the solid-state imaging device in the operating state, and the calculated defect component is calculated for the defective pixel. The defect component included in the pixel signal of the defective pixel is removed by subtracting from the pixel signal.

Hereinafter, an image pickup apparatus and a pixel signal correction method according to Embodiment 1 of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram illustrating a schematic configuration of the imaging apparatus according to the first embodiment.
As shown in FIG. 1, the imaging apparatus according to the first embodiment includes a lens 1, an aperture 2, a solid-state imaging device 3, a CDS (Correlated Double Sampling) circuit 4, an AD (Analog to Digital) conversion circuit 5, and a white point detection correction circuit. 6, an image processing circuit 7, a CPU 8, a white point ROM 9, an image RAM 10, and a recording medium 11.

  The lens 1 forms an image of incident light on the solid-state image sensor 3. The diaphragm 2 adjusts the amount of incident light of the solid-state image sensor 3 and serves as a mechanical shutter. The solid-state imaging device 3 is composed of, for example, a CCD (Charge Coupled Device), and has a plurality of pixels that convert incident light into signal charges and output them as pixel signals, and pixel signals output by the plurality of pixels. (Image) is output. The CDS circuit 4 performs correlated double sampling processing on the pixel signal output from the solid-state imaging device 3 to remove noise contained in the pixel signal. The AD conversion circuit 5 converts the analog pixel signal output from the CDS circuit 4 into a digital pixel signal. The white point detection / correction circuit 6 detects a white point (defective pixel) of the solid-state imaging device 3 based on the digital pixel signal output from the AD conversion circuit 5 and corrects the detected white point pixel signal. The white point detection by the white point detection correction circuit 6 is performed by the manufacturer at the time of inspection before shipment of the imaging apparatus.

  The image processing circuit 7 performs various image processing such as gamma correction on the pixel signal output from the white point detection correction circuit 6 and outputs the result. CPU8 controls each part of this imaging device. The white point ROM 9 stores the address of the white point detected by the white point detection / correction circuit 6 at the time of inspection of the imaging apparatus and its ratio (described later) in association with each other. The white point detection / correction circuit 6 reads the white point address and ratio stored in the white point ROM 9 at the time of photographing after purchase of the imaging apparatus, and corrects the white point pixel signal corresponding to the address based on the ratio. To do. The image RAM 10 serves as a buffer memory for the pixel signal output from the image processing circuit 7, and serves as a working memory when the white point detection / correction circuit 6 detects the white point of the solid-state imaging device 3. The recording medium 11 is an exchangeable recording medium such as a video tape or a memory card, and records the pixel signal (image) output from the image processing circuit 7.

FIG. 2 is a diagram illustrating a configuration of a pixel portion of the solid-state imaging device illustrated in FIG.
As shown in FIG. 2, the pixel unit 20 of the solid-state imaging device 3 includes an effective pixel unit 21, a front horizontal OPB (Optical Black) unit 22, a horizontal rear OPB unit 23, a horizontal transfer register 24, and an output circuit 25.

The effective pixel unit 21 is arranged in a matrix and takes out a plurality of effective pixels (not shown) that convert incident light into signal charges and outputs them as pixel signals, and extracts pixel signals for each of the plurality of effective pixels for each column. And a plurality of columns of vertical transfer registers (not shown) for transferring in the vertical direction.
The plurality of effective pixels have a color filter of any one color of R (Red), G (Green), and B (Blue) that transmits incident light. The plurality of effective pixels receive light through a color filter, convert the incident light into a signal charge, and output it as a pixel signal. The vertical transfer register has the same number of transfer elements as the number of rows of a plurality of effective pixels, and transfers pixel signals in the vertical direction for each pixel by these transfer elements. The vertical transfer register is formed with a light shielding film that shields incident light.

The pre-horizontal OPB unit 22 takes out a plurality of light-shielded pixels (not shown) arranged in a matrix in the same row as a plurality of effective pixels, and extracts a pixel signal for each column of the plurality of light-shielded pixels and transfers them in the vertical direction. Column vertical transfer registers (not shown).
A plurality of light shielding pixels and a plurality of columns of vertical transfer registers are formed with a light shielding film that shields incident light. Since the plurality of light shielding pixels are shielded from light, charges that are not related to light are accumulated. The plurality of light shielding pixels are used to detect an optical black level during operation of the solid-state imaging device 3. The plurality of columns of vertical transfer registers have the same configuration as that of the effective pixel unit 21.

The horizontal post-OPB unit 23 includes a plurality of columns of vertical transfer registers (not shown).
A plurality of columns of vertical transfer registers are formed with a light shielding film that shields incident light. The plurality of columns of vertical transfer registers have the same configuration as that of the effective pixel unit 21. The vertical transfer registers of a plurality of columns transfer pixel signals having a pixel value of 0. The plurality of columns of vertical transfer registers are used to detect a no-signal level during operation of the solid-state imaging device 3.

  The horizontal transfer register 24 takes out pixel signals transferred in the vertical direction by a plurality of columns of vertical transfer registers of the effective pixel unit 21, the horizontal pre-OPB unit 22 and the horizontal post-OPB unit 23, and transfers them in the horizontal direction. The horizontal transfer register 24 has the same number of transfer elements as the number of columns of the vertical transfer registers of the effective pixel unit 21, the horizontal front OPB unit 22, and the horizontal post OPB unit 23, and these transfer elements send pixel signals for each pixel. Transfer horizontally. The output circuit 25 converts the pixel signal (signal charge) transferred in the horizontal direction by the horizontal transfer register 24 into a voltage and outputs the voltage to the CDS circuit 4 in the next stage.

FIG. 3 is an explanatory diagram of pixel signals output by the solid-state imaging device shown in FIG.
Here, it is assumed that light with uniform brightness is incident on the solid-state imaging device 3. In addition, the influence of the color filter of the effective pixel is ignored.
As shown in FIG. 3, when one line of the solid-state imaging device 3 is scanned, pixel signals having different levels are obtained in the effective pixel unit 21, the horizontal front OPB unit 22, and the horizontal rear OPB unit 23, respectively.
The level of the pixel signal in the blanking area without the effective pixel unit 21, the pre-horizontal OPB unit 22, and the horizontal post-OPB unit 23 is “0”. The pixel signal obtained from the post-horizontal OPB unit 23 is a non-signal level pixel signal, which is due to the dark current caused by the vertical transfer register generated by the transfer of the vertical transfer register. The pixel signal obtained from the pre-horizontal OPB unit 22 is an optical black level pixel signal, and includes a dark current caused by a sensor of a light-shielded pixel that is accumulated and converted regardless of light, and a dark current caused by a vertical transfer register. . The pixel signal obtained from the effective pixel unit 21 is a pixel signal at an optical signal level, which is derived from a light-induced signal of an effective pixel obtained by photoelectric conversion of incident light and a sensor-derived effective pixel accumulated and converted irrespective of the light. The dark current and the dark current caused by the vertical transfer register are included.

  In other words, when light is incident on the solid-state imaging device 3, the effective pixel unit 21 without the light-shielding film outputs a pixel signal at an optical signal level including a light-induced signal, a sensor-induced dark current, and a vertical transfer register-derived dark current. The horizontal front OPB unit 22 on which the light shielding film is formed outputs an optical black level pixel signal including a dark current caused by the sensor and a dark current caused by the vertical transfer register, and the horizontal post-OPB unit 23 performs the vertical transfer. A non-signal level pixel signal including dark current caused by the register is output.

FIG. 4 is a diagram illustrating an example of a white spot of the solid-state imaging device. FIG. 5 is an explanatory diagram of pixel signals output from a solid-state imaging device having a white point.
When the solid-state imaging device 3 is operated in a light-shielded state, as shown in FIG. 4, a bright white spot (shown by two in FIG. 4) is generated in the output image. When one line (XX ′ plane) of this image is scanned, as shown in FIG. 5, a signal level that protrudes steeply with respect to other portions of the effective pixel portion 21 is obtained. As described in the background art section, this is due to the dark current caused by the sensor that is generated when the semiconductor constituting the effective pixel is contaminated by metal ions or the crystallinity of the semiconductor is damaged. .

FIG. 6 is a diagram showing a configuration of the white spot detection correction circuit shown in FIG.
As described above, the white point detection / correction circuit 6 detects the white point (defective pixel) of the solid-state image sensor 3 at the time of inspection before shipment of the imaging device, and at the time of shooting after purchase of the imaging device (during normal shooting) The white spot address and ratio (described later) stored in the white spot ROM 9 are read out, and the pixel signal corresponding to the address is corrected based on this ratio. The white point is detected by operating the solid-state imaging device 3 in a light-shielded state.
As shown in FIG. 6, the white point detection correction circuit 6 includes a white point detection unit 31, a sensor-induced dark current calculation unit 32, a ratio calculation unit 33, a white point storage control unit 34, and a white point correction unit 35.

  The white spot detection unit 31 detects a white spot based on the pixel signal output from the solid-state imaging device 3. For example, the white point detection circuit 31 detects a difference in signal level between a target pixel to be inspected and a peripheral pixel, and determines that a white point is detected when the difference in signal level is equal to or greater than a threshold value. The white point detection circuit 31 is configured to cumulatively add pixel signals at the same position in a plurality of images output from the solid-state imaging device 3 and compare the cumulatively added pixel signals to detect a white point. can do. In this case, it is possible to eliminate the random noise of the solid-state imaging device 3 and detect the white spot with higher accuracy. Note that the image RAM 10 is used for cumulative addition of pixel signals.

  The sensor-induced dark current calculation means 32 is a pixel signal (for example, an average value of pixel values of a plurality of light-shielded pixels) extracted from the plurality of light-shielded pixels of the front horizontal OPB unit 22 of the pixel unit 20 and output from the solid-state imaging device 3. The pixel signal transferred from the horizontal post-OPB unit 23 of the pixel unit 20 and output from the solid-state image sensor 3 (for example, the average value of the pixel values of a plurality of transfer elements constituting the vertical transfer register) is subtracted from The sensor-induced dark current of the plurality of effective pixels of the unit 21 and the plurality of light-shielded pixels of the horizontal front OPB unit 22 is calculated.

  The ratio calculation means 33 is a white point pixel signal detected by the white point detection means 31 and the sensor-induced dark current calculation means 32 when the solid-state imaging device 3 is operated in a light-shielded state during inspection before shipment of the image pickup apparatus. The ratio with the sensor-induced dark current calculated by is calculated. The white point storage control unit 34 associates the address of the white point detected by the white point detection unit 31 with the ratio of the corresponding white point calculated by the ratio calculation unit 33 and stores it in, for example, the white point ROM 9.

  The white point correction means 35 reads the white point address and ratio stored in the white point ROM 9 and corrects the white point pixel signal corresponding to the address output by the solid-state image sensor 3 based on this ratio. Specifically, the pixel signal of the white point is obtained by multiplying the sensor-induced dark current calculated by the sensor-derived dark current calculation means 32 at the time of normal photographing performed by the user after shipment of the imaging device by the white point ratio. The white dot pixel signal is corrected by subtracting the calculated defect component from the white dot pixel signal.

FIG. 7 is a diagram showing characteristics of sensor-induced dark current, white point, and vertical transfer register-induced current.
As described above, the white point pixel signal includes the vertical transfer register-induced dark current, the sensor-induced dark current, and the white point itself dark current, and the relationship shown in FIG. 7 has been found. That is, the white point pixel signal and the sensor-induced dark current depend on the temperature of the solid-state imaging device 3 and the exposure time, and have a linear relationship. These double approximately as the temperature increases by 10 ° C. Also, it increases as the exposure time increases. On the other hand, the dark current caused by the vertical transfer register has a linear relationship with the temperature, but does not depend on the exposure time and has a substantially constant relationship with the exposure time. This is because the vertical transfer register is always driven regardless of exposure.
Therefore, if the sensor-induced dark current changes according to the temperature and the exposure time, the white point pixel signal changes in the same manner, so the ratio of the white point pixel signal to the sensor-induced dark current and the sensor-induced dark current Based on this, it is possible to obtain the defect component of the white point pixel signal by calculation.
For example, when the white point pixel signal in the light-shielding state is “10” and the sensor-induced dark current is “2”, the ratio of the white point pixel signal to the sensor-induced dark current is “5”. During normal shooting, when the sensor-induced dark current is “4”, the sensor-induced dark current is twice that of the sensor-induced dark current during light shielding. The value is doubled and the value is “20”. Then, by subtracting the defect component obtained by the calculation from the white point pixel signal, a correct white point pixel signal from which the defect component has been removed can be obtained.

Next, the operation at the time of inspection before shipment of the image pickup apparatus of Embodiment 1 will be described.
Imaging with the imaging device is performed in a light-shielded state with the aperture 2 closed. Charges are accumulated regardless of light by the plurality of effective pixels of the effective pixel unit 21 of the screen unit 20 of the solid-state imaging device 3 and the plurality of light-shielding pixels of the horizontal OPB 22. Next, signal charges accumulated in a plurality of effective pixels and a plurality of light-shielded pixels are taken out by the respective vertical transfer registers as pixel signals and transferred in the vertical direction. At the same time, a pixel signal having a pixel value “0” is transferred in the vertical direction by the vertical transfer register of the post-horizontal OPB unit 23. Then, the pixel signals transferred in the vertical direction by the vertical transfer registers of the effective pixel unit 21, the pre-horizontal OPB unit 22 and the horizontal post-OPB unit 23 are transferred in the horizontal direction by the horizontal transfer register 24, and the output circuit 25 outputs the pixel signal. The signal (signal charge) is converted into a voltage and output to the CDS circuit 4 at the next stage.

The pixel signal output from the solid-state imaging device 3 is denoised by the CDS circuit 4, converted from an analog pixel signal to a digital pixel signal by the AD conversion circuit 5, and input to the white point detection correction circuit 6.
Here, a method of detecting a white point and storing the white point address and ratio (ratio between the pixel signal and the sensor-induced dark current) will be described in steps S1 to S4.
A white spot of the solid-state imaging device 3 is detected by the white spot detection circuit 31. Specifically, the white point detection means 31 detects a difference in signal level (pixel signal) between the target pixel and the surrounding pixels, and when the difference in signal level is equal to or greater than a threshold value, the white point is determined (step). S1). Next, the sensor-derived dark current calculation means 32 subtracts the average value of the plurality of pixel signals from the horizontal rear OPB unit 23 from the average value of the pixel signals of the plurality of light-shielded pixels of the horizontal front OPB unit 22, thereby obtaining the sensor-induced dark current. Is calculated (step S2). Next, the ratio between the white point pixel signal detected by the white point detection unit 31 and the sensor-induced dark current calculated by the sensor-derived dark current calculation unit 32 is calculated by the ratio calculation unit (step S3). Then, the white point address detected by the white point detection unit 31 by the white point storage control unit 34 is associated with the ratio of the corresponding white point calculated by the ratio calculation unit 33 and stored in the white point ROM 9. (Step S4).

Next, the operation at the time of normal shooting of the image pickup apparatus of Embodiment 1 will be described.
When light enters the solid-state image sensor 3 through the lens 1 and the diaphragm 2, charges corresponding to the light amount are accumulated by the plurality of effective pixels of the effective pixel unit 21 of the pixel unit 20 of the solid-state image sensor 3. At the same time, charges are accumulated in the plurality of light-shielding pixels of the front horizontal OPB unit 22 regardless of light.
Next, signal charges accumulated in a plurality of effective pixels and a plurality of light-shielded pixels are taken out by the respective vertical transfer registers as pixel signals and transferred in the vertical direction. At the same time, a pixel signal having a pixel value “0” is transferred in the vertical direction by the vertical transfer register of the post-horizontal OPB unit 23. Then, the pixel signals transferred in the vertical direction by the vertical transfer registers of the effective pixel unit 21, the pre-horizontal OPB unit 22 and the horizontal post-OPB unit 23 are transferred in the horizontal direction by the horizontal transfer register 24, and the output circuit 25 outputs the pixel signal. The signal (signal charge) is converted into a voltage and output to the CDS circuit 4 at the next stage.

  The pixel signal output from the solid-state imaging device 3 is denoised by the CDS circuit 4, converted from an analog pixel signal to a digital pixel signal by the AD conversion circuit 5, and input to the white point detection correction circuit 6.

Here, a method for correcting the white point pixel signal will be described in steps S11 to S13.
The sensor-derived dark current calculation means 32 subtracts the average value of the plurality of pixel signals from the horizontal post-OPB unit 23 from the average value of the pixel signals of the plurality of light-shielded pixels of the horizontal front OPB unit 22 to calculate the sensor-induced dark current. (Step S11). Next, the white spot address and ratio stored in the white spot ROM 9 are read by the white spot correction means 35, and the ratio of each white spot is multiplied by the sensor-derived dark current calculated by the sensor-derived dark current calculation means 32. Then, the defect component of each white point pixel signal is calculated (step S12). Next, the corresponding defect component calculated from the white point pixel signal corresponding to the address output from the solid-state imaging device 3 by the white point correction unit 35 is subtracted, and the defect component is removed from the white point pixel signal. Thus, the pixel signal is corrected (step S13).

  The pixel signal corrected by removing the defect component is output to the image processing circuit 7 in the next stage, and subjected to image processing such as gamma correction. The pixel signal output by the image processing circuit 7 is stored in the image RAM 10 and then output externally or recorded on the recording medium 11.

As described above, according to the imaging apparatus of the first embodiment, the white point detection and correction circuit 6 detects the white point of the solid-state imaging device 3 and corrects the pixel signal. Therefore, it is possible to obtain an image with good image quality without white spots.
Further, the white point is detected by the white point detection and correction circuit 6 and the white point address and ratio are stored in the white point ROM 9. Therefore, it is not necessary to detect a white spot by a dedicated detection device, and the white spot can be easily detected.

Also, the white point is obtained by multiplying the sensor-induced dark current of the solid-state image sensor in the operating state by the ratio of the white-point pixel signal of the solid-state image sensor and the sensor-induced dark current obtained in the light-shielded state by the white point detection correction circuit 6 The defect component included in the pixel signal is calculated, and the calculated defect component is subtracted from the white point pixel signal to remove the defect component of the white point pixel signal.
Therefore, since the dark current itself caused by the sensor of the solid-state imaging device depending on the temperature and the exposure time can be detected and the white point can be corrected, the white point can be corrected with high accuracy.

  Further, since the white spot address and the ratio are stored in association with each other, the memory capacity can be reduced. There is no need for a calculation table in which the temperature and the correction amount are associated with each other. Further, since it is not necessary to replace the white point pixel signal based on the peripheral pixels, the edge portion can be corrected correctly and a sharp image can be obtained without reducing the image resolution.

8 to 11 are diagrams showing modifications of the pixel portion of the solid-state imaging device shown in FIG.
The positions of the front horizontal OPB unit 22 and the horizontal rear OPB unit 23 shown in FIG. 2 may be reversed. In other words, as shown in FIG. 8, a horizontal front OPB unit 26 and a horizontal rear OPB unit 27 that are adjacent in the horizontal direction of the effective pixel unit 21 are provided, and the horizontal front OPB unit 26 is configured by a plurality of columns of vertical registers. The rear OPB unit 27 may be composed of a plurality of light shielding pixels and a plurality of columns of vertical transfer registers.

  In the pixel unit 20 shown in FIG. 2, the sensor-induced dark current of the solid-state imaging device 3 is calculated based on the pixel signals of the pre-horizontal OPB unit 22 and the horizontal post-OPB unit 23. The horizontal front OPB portion 22 and the horizontal rear OPB portion 23 constitute an optical black region for obtaining an optical black level, which is well known conventionally. On the other hand, a dedicated OPB unit for calculating the sensor-induced dark current of the solid-state imaging device 3 may be provided.

FIG. 9 shows that the optical black level unit 61 having a plurality of light-shielding pixels and a plurality of columns of vertical transfer registers and the no-signal level unit 62 having a plurality of columns of vertical transfer registers are adjacent to the horizontal OPB unit 22 in the horizontal direction. It is an example arranged side by side.
The optical black level unit 61 only needs to have at least one column of light-shielded pixels and a vertical transfer register, and the no-signal level unit 62 only needs to have at least one column of a vertical transfer register.

10 shows that the optical black level unit 61 having a plurality of light-shielding pixels and a plurality of columns of vertical transfer registers and the no-signal level unit 62 having a plurality of columns of vertical transfer registers are adjacent to each other in the horizontal direction of the rear rear OPB unit 23. It is an example arranged side by side.
The optical black level unit 61 only needs to have at least one column of light-shielded pixels and a vertical transfer register, and the no-signal level unit 62 only needs to have at least one column of a vertical transfer register.

FIG. 11 shows an optical black level portion 63 having a plurality of light-shielding pixels and a plurality of columns of vertical transfer registers and a non-signal level portion 64 having a plurality of columns of vertical transfer registers. In this example, the rear OPB unit 23 is arranged so as to be adjacent to each other in the vertical direction.
The optical black level unit 63 only needs to have at least one row of light-shielding pixels and a vertical transfer register (transfer element), and the no-signal level unit 62 has at least one row of vertical transfer register (transfer element). do it.

  The plurality of light-shielding pixels of the optical black level portions 61 and 63 shown in FIGS. 9 to 11 can be configured to generate a larger dark current than the plurality of effective pixels of the effective pixel portion 21. As a result, the sensor-induced dark current can be easily detected, so that the sensor-induced dark current of the solid-state imaging device 3 can be obtained with high accuracy.

1 is a diagram illustrating a schematic configuration of an imaging apparatus according to Embodiment 1. FIG. It is a figure which shows the structure of the pixel part of the solid-state image sensor shown by FIG. It is explanatory drawing of the pixel signal output by the solid-state image sensor shown by FIG. It is a figure which shows an example of the white spot of a solid-state image sensor. It is explanatory drawing of the pixel signal output by the solid-state image sensor which has a white point. It is a figure which shows the structure of the white point detection correction circuit shown by FIG. It is a figure which shows the characteristic of a sensor-induced dark current, a white point, and a vertical transfer register-induced current. It is a figure which shows the modification of the pixel part of the solid-state image sensor shown by FIG. It is a figure which shows the modification of the pixel part of the solid-state image sensor shown by FIG. It is a figure which shows the modification of the pixel part of the solid-state image sensor shown by FIG. It is a figure which shows the modification of the pixel part of the solid-state image sensor shown by FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Lens, 2 ... Diaphragm, 3 ... Solid-state image sensor, 4 ... CDS circuit, 5 ... AD conversion circuit, 6 ... Linear defect detection correction circuit, 7 ... Image processing circuit, 8 ... CPU, 9 ... White dot ROM, 10 ... Image RAM, 20 ... Pixel unit 20, 21 ... Effective pixel unit, 22 ... Horizontal rear OPB unit, 23 ... Horizontal rear OPB unit, 24 ... Horizontal transfer Register, 25... Output circuit, 31... White point detecting means, 32... Sensor-induced dark current calculating means, 33 .. Ratio calculating means, 34.

Claims (18)

A solid-state imaging device that outputs a pixel signal; and a correction unit that corrects the pixel signal output by the solid-state imaging device;
The solid-state imaging device is
A plurality of effective pixels arranged in a matrix that converts incident light into signal charges and outputs them as pixel signals;
A plurality of light shielding pixels arranged around the plurality of effective pixels so as to form a matrix together with the plurality of effective pixels and covered with a light shielding film;
Each of the plurality of effective pixels and the plurality of light shielding units includes at least one pixel transfer unit of an effective pixel transfer unit that extracts pixel signals of the plurality of effective pixels and a light shielding pixel transfer unit that extracts image signals of the plurality of light shielding pixels. An effective / light-shielding pixel unit having a plurality of effective / light-shielding pixel vertical transfer registers that extract pixel signals for each column of pixels and transfer them in the vertical direction;
One or a plurality of invalid pixel vertical transfer registers arranged in a column or matrix around the effective / light-shielding pixel portion and transferring a pixel signal having a pixel value of 0 in the vertical direction;
An image pickup apparatus comprising: a plurality of valid / light-shielded pixel vertical transfer registers; and a horizontal transfer register that transfers pixel signals transferred by the one or more invalid pixel vertical transfer registers in a horizontal direction,
The correction means includes
When the solid-state image sensor is operated in a light-shielded state, the solid-state image sensor is transferred by the invalid pixel vertical transfer register from pixel signals of the plurality of light-shielded pixels output by the light-shielded pixel transfer unit and output by the solid-state image sensor. The solid-state imaging detected based on the pixel signal output by the solid-state imaging device when the solid-state imaging device is operated in a light-shielded state using a sensor-induced dark current obtained by subtracting the pixel signal output by the imaging device Defective pixel storage means for storing the address of the defective pixel of the element, the ratio of the pixel signal of the defective pixel corresponding to the address and the sensor-induced dark current in association with each other;
A pixel signal transferred by the invalid pixel vertical transfer register and output from the solid-state image sensor and subtracted from a pixel signal of the plurality of light-shielded pixels output by the solid-state image sensor taken out by the light-shielded pixel transfer unit; A sensor-induced dark current calculating means for calculating the induced dark current;
The defective pixel address stored in the defective pixel storage means and the corresponding ratio are read out, the sensor-induced dark current calculated by the sensor-derived dark current calculation means is multiplied by the ratio, and the defect of the pixel signal of the defective pixel A defect component calculating means for calculating a component;
The defective pixel output by the solid-state imaging device is obtained by subtracting the defective component of the pixel signal of the corresponding defective pixel calculated by the defective component calculating means from the pixel signal of the defective pixel at the address output by the solid-state imaging device. A defect component removing means for removing the defect component from the pixel signal of
An imaging apparatus characterized by that.   The correction means includes defective pixel detection means for detecting a defective pixel of the solid-state image sensor based on a pixel signal output from the solid-state image sensor when the solid-state image sensor is operated in a light-shielded state. The imaging apparatus according to claim 1.   The defective pixel detection means includes cumulative addition means for cumulatively adding pixel signals at the same position in a plurality of images output from the solid-state imaging device, and the plurality of the same number of the plurality of sheets that have been cumulatively added by the cumulative addition means. The imaging apparatus according to claim 2, wherein a defective pixel is detected based on a pixel signal at a position. The correction means includes ratio calculation means for calculating a ratio between a pixel signal of the defective pixel detected by the defective pixel detection means and a sensor-induced dark current calculated by the sensor-derived dark current calculation means,
When a defective pixel is detected by the defective pixel detection means, a sensor-induced dark current is calculated by the sensor-induced dark current calculation means, and a pixel signal of the defective pixel detected by the defective pixel detection means by the ratio calculation means The ratio of the sensor-induced dark current calculated by the sensor-induced dark current calculation means is calculated, and the defective pixel address detected by the defective pixel detection means by the defective pixel storage means is calculated by the ratio calculation means. The imaging apparatus according to claim 2, wherein a ratio of defective pixels corresponding to the address is stored in association with each other.   The imaging device according to claim 1, wherein the light-shielding pixel is configured to generate a larger dark current than the effective pixel.   The imaging device according to claim 1, wherein the plurality of light-shielding pixels constitute an optical black region for detecting a black level of a pixel signal.   The imaging apparatus according to claim 1, wherein the invalid pixel vertical transfer register forms an optical black region for detecting a black level of a pixel signal. A solid-state imaging device that outputs a pixel signal; and a correction unit that corrects the pixel signal output by the solid-state imaging device;
The solid-state imaging device is
A plurality of effective pixels arranged in a matrix that converts incident light into signal charges and outputs them as pixel signals;
A plurality of light shielding pixels arranged around the plurality of effective pixels so as to form a matrix together with the plurality of effective pixels and covered with a light shielding film;
Each of the plurality of effective pixels and the plurality of light shielding units includes at least one pixel transfer unit of an effective pixel transfer unit that extracts pixel signals of the plurality of effective pixels and a light shielding pixel transfer unit that extracts image signals of the plurality of light shielding pixels. An effective / light-shielding pixel unit having a plurality of effective / light-shielding pixel vertical transfer registers that extract pixel signals for each column of pixels and transfer them in the vertical direction;
One or a plurality of invalid pixel vertical transfer registers arranged in a column or matrix around the effective / light-shielding pixel portion and transferring a pixel signal having a pixel value of 0 in the vertical direction;
A solid-state imaging device having a horizontal transfer register that horizontally transfers pixel signals transferred by the plurality of valid / light-shielded pixel vertical transfer registers and the one or more invalid pixel vertical transfer registers,
The correction means includes
Defective pixel detection means for detecting a defective pixel of the solid-state image sensor based on a pixel signal output by the solid-state image sensor when the solid-state image sensor is operated in a light-shielded state;
When the solid-state image sensor is operated in a light-shielded state, the solid-state image sensor is transferred from the pixel signals of the plurality of light-shielded pixels extracted by the light-shielded pixel transfer unit and output by the solid-state image sensor, and transferred by the invalid pixel vertical transfer register. A first sensor-induced dark current calculation means for subtracting a pixel signal output by the element and calculating a sensor-induced dark current;
A ratio calculating means for calculating a ratio between a pixel signal of the defective pixel detected by the defective pixel detecting means and a sensor-induced dark current calculated by the first sensor-derived dark current calculating means;
Defective pixel storage means for storing the address of the defective pixel detected by the defective pixel detection means and the ratio of the defective pixel corresponding to the address calculated by the ratio calculation means in association with each other;
The sensor signal is derived by subtracting the pixel signal transferred by the invalid pixel vertical transfer register and output by the solid-state image sensor from the pixel signals of the plurality of light-shielded pixels output by the light-shielded pixel transfer unit and output by the solid-state image sensor. A second sensor-derived dark current calculating means for calculating dark current;
The defective pixel address stored in the defective pixel storage means and the corresponding ratio are read, the sensor-induced dark current calculated by the second sensor-derived dark current calculation means is multiplied by the ratio, and the pixel of the defective pixel A defect component calculating means for calculating a defect component of the signal;
The defective pixel output by the solid-state imaging device is obtained by subtracting the defective component of the pixel signal of the corresponding defective pixel calculated by the defective component calculating means from the pixel signal of the defective pixel at the address output by the solid-state imaging device. A defect component removing means for removing the defect component from the pixel signal of
An imaging apparatus characterized by that. A plurality of effective pixels arranged in a matrix that converts incident light into signal charges and outputs them as pixel signals;
A plurality of light shielding pixels arranged around the plurality of effective pixels so as to form a matrix together with the plurality of effective pixels and covered with a light shielding film;
Each of the plurality of effective pixels and the plurality of light shielding units includes at least one pixel transfer unit of an effective pixel transfer unit that extracts pixel signals of the plurality of effective pixels and a light shielding pixel transfer unit that extracts image signals of the plurality of light shielding pixels. An effective / light-shielding pixel unit having a plurality of effective / light-shielding pixel vertical transfer registers that extract pixel signals for each column of pixels and transfer them in the vertical direction;
One or a plurality of invalid pixel vertical transfer registers arranged in a column or matrix around the effective / light-shielding pixel portion and transferring a pixel signal having a pixel value of 0 in the vertical direction;
A pixel signal output by a solid-state imaging device including a horizontal transfer register that horizontally transfers pixel signals transferred by the plurality of valid / light-shielded pixel vertical transfer registers and the one or more invalid pixel vertical transfer registers. A correction method of a pixel signal to be corrected,
A defective pixel detection step of detecting a defective pixel of the solid-state image sensor based on a pixel signal output by the solid-state image sensor when the solid-state image sensor is operated in a light-shielded state;
When the solid-state image sensor is operated in a light-shielded state, the solid-state image sensor is transferred from the pixel signals of the plurality of light-shielded pixels extracted by the light-shielded pixel transfer unit and output by the solid-state image sensor, and transferred by the invalid pixel vertical transfer register. A first sensor-induced dark current calculation step of subtracting a pixel signal output by the element and calculating a sensor-induced dark current;
A ratio calculation step of calculating a ratio between a pixel signal of the defective pixel detected in the defective pixel detection step and a sensor-induced dark current calculated in the first sensor-induced dark current calculation step;
A defective pixel storage step for storing the address of the defective pixel detected in the defective pixel detection step and the ratio of the defective pixel corresponding to the address calculated in the ratio calculation step in association with each other;
The sensor signal is derived by subtracting the pixel signal transferred by the invalid pixel vertical transfer register and output by the solid-state image sensor from the pixel signals of the plurality of light-shielded pixels output by the light-shielded pixel transfer unit and output by the solid-state image sensor. A second sensor-derived dark current calculation step for calculating dark current;
The defective pixel address stored in the defective pixel storage step and the corresponding ratio are read out, the sensor-induced dark current calculated in the second sensor-derived dark current calculation step is multiplied by the ratio, and the pixel of the defective pixel A defect component calculation step for calculating a defect component of the signal;
The defective pixel output by the solid-state imaging device is obtained by subtracting the defective component of the pixel signal of the corresponding defective pixel calculated in the defective component calculation step from the pixel signal of the defective pixel at the address output by the solid-state imaging device. Removing a defect component from the pixel signal of the defect component,
A method for correcting a pixel signal. A solid-state imaging device that outputs a pixel signal; and a correction unit that corrects the pixel signal output by the solid-state imaging device;
The solid-state imaging device
A plurality of effective pixels arranged in a matrix that converts incident light into signal charges and outputs them as pixel signals;
A plurality of light shielding pixels arranged around the plurality of effective pixels so as to form a matrix together with the plurality of effective pixels and covered with a light shielding film;
Each of the plurality of effective pixels and the plurality of light shielding units includes at least one pixel transfer unit of an effective pixel transfer unit that extracts pixel signals of the plurality of effective pixels and a light shielding pixel transfer unit that extracts image signals of the plurality of light shielding pixels. An effective / light-shielding pixel unit having a plurality of effective / light-shielding pixel vertical transfer registers that extract pixel signals for each column of pixels and transfer them in the vertical direction;
One or a plurality of invalid pixel verticals arranged in a row or matrix around the effective / light-shielded pixel portion and transferring a pixel signal having a pixel value of 0 in the vertical direction to the valid / light-shielded pixel vertical transfer register A transfer register;
A horizontal transfer register for horizontally transferring pixel signals transferred by the plurality of effective / light-shielded pixel vertical transfer registers,
The correction means includes
When the solid-state image sensor is operated in a light-shielded state, the solid-state image sensor is transferred by the invalid pixel vertical transfer register from pixel signals of the plurality of light-shielded pixels output by the light-shielded pixel transfer unit and output by the solid-state image sensor. The solid-state imaging detected based on the pixel signal output by the solid-state imaging device when the solid-state imaging device is operated in a light-shielded state using a sensor-induced dark current obtained by subtracting the pixel signal output by the imaging device Defective pixel storage means for storing the address of the defective pixel of the element, the ratio of the pixel signal of the defective pixel corresponding to the address and the sensor-induced dark current in association with each other;
A pixel signal transferred by the invalid pixel vertical transfer register and output from the solid-state image sensor and subtracted from a pixel signal of the plurality of light-shielded pixels output by the solid-state image sensor taken out by the light-shielded pixel transfer unit; A sensor-induced dark current calculating means for calculating the induced dark current;
The defective pixel address stored in the defective pixel storage means and the corresponding ratio are read out, the sensor-induced dark current calculated by the sensor-derived dark current calculation means is multiplied by the ratio, and the defect of the pixel signal of the defective pixel A defect component calculating means for calculating a component;
The defective pixel output by the solid-state imaging device is obtained by subtracting the defective component of the pixel signal of the corresponding defective pixel calculated by the defective component calculating means from the pixel signal of the defective pixel at the address output by the solid-state imaging device. A defect component removing means for removing the defect component from the pixel signal of
An imaging apparatus characterized by that.   The correction means includes defective pixel detection means for detecting a defective pixel of the solid-state image sensor based on a pixel signal output from the solid-state image sensor when the solid-state image sensor is operated in a light-shielded state. The imaging apparatus according to claim 10.   The defective pixel detection means includes cumulative addition means for cumulatively adding pixel signals at the same position in a plurality of images output from the solid-state imaging device, and the plurality of the same number of the plurality of sheets that have been cumulatively added by the cumulative addition means. The imaging apparatus according to claim 11, wherein a defective pixel is detected based on a pixel signal of a position. The correction means includes ratio calculation means for calculating a ratio between a pixel signal of the defective pixel detected by the defective pixel detection means and a sensor-induced dark current calculated by the sensor-derived dark current calculation means,
When a defective pixel is detected by the defective pixel detection means, a sensor-induced dark current is calculated by the sensor-induced dark current calculation means, and a pixel signal of the defective pixel detected by the defective pixel detection means by the ratio calculation means The ratio of the sensor-induced dark current calculated by the sensor-induced dark current calculation means is calculated, and the defective pixel storage means calculates the defective pixel address detected by the defective pixel detection means and the ratio calculation means. 12. The image pickup apparatus according to claim 11, wherein a ratio of defective pixels corresponding to the address is stored in association with each other.   The imaging device according to claim 10, wherein the light-shielding pixel is configured to generate a larger dark current than the effective pixel.   The imaging device according to claim 10, wherein the plurality of light shielding pixels constitute an optical black region for detecting a black level of a pixel signal.   The image pickup apparatus according to claim 10, wherein the invalid pixel vertical transfer register forms an optical black region for detecting a black level of a pixel signal. A solid-state imaging device that outputs a pixel signal; and a correction unit that corrects the pixel signal output by the solid-state imaging device;
The solid-state imaging device
A plurality of effective pixels arranged in a matrix that converts incident light into signal charges and outputs them as pixel signals;
A plurality of light shielding pixels arranged around the plurality of effective pixels so as to form a matrix together with the plurality of effective pixels and covered with a light shielding film;
Each of the plurality of effective pixels and the plurality of light shielding units includes at least one pixel transfer unit of an effective pixel transfer unit that extracts pixel signals of the plurality of effective pixels and a light shielding pixel transfer unit that extracts image signals of the plurality of light shielding pixels. An effective / light-shielding pixel unit having a plurality of effective / light-shielding pixel vertical transfer registers that extract pixel signals for each column of pixels and transfer them in the vertical direction;
One or a plurality of invalid pixel verticals arranged in a row or matrix around the effective / light-shielded pixel portion and transferring a pixel signal having a pixel value of 0 in the vertical direction to the valid / light-shielded pixel vertical transfer register A transfer register;
A horizontal transfer register for horizontally transferring pixel signals transferred by the plurality of effective / light-shielded pixel vertical transfer registers,
The correction means includes
Defective pixel detection means for detecting a defective pixel of the solid-state image sensor based on a pixel signal output by the solid-state image sensor when the solid-state image sensor is operated in a light-shielded state;
When the solid-state image sensor is operated in a light-shielded state, the solid-state image sensor is transferred from the pixel signals of the plurality of light-shielded pixels extracted by the light-shielded pixel transfer unit and output by the solid-state image sensor, and transferred by the invalid pixel vertical transfer register. A first sensor-induced dark current calculation means for subtracting a pixel signal output by the element and calculating a sensor-induced dark current;
A ratio calculating means for calculating a ratio between a pixel signal of the defective pixel detected by the defective pixel detecting means and a sensor-induced dark current calculated by the first sensor-derived dark current calculating means;
Defective pixel storage means for storing the address of the defective pixel detected by the defective pixel detection means and the ratio of the defective pixel corresponding to the address calculated by the ratio calculation means in association with each other;
The sensor signal is derived by subtracting the pixel signal transferred by the invalid pixel vertical transfer register and output by the solid-state image sensor from the pixel signals of the plurality of light-shielded pixels output by the light-shielded pixel transfer unit and output by the solid-state image sensor. A second sensor-derived dark current calculating means for calculating dark current;
The defective pixel address stored in the defective pixel storage means and the corresponding ratio are read, the sensor-induced dark current calculated by the second sensor-derived dark current calculation means is multiplied by the ratio, and the pixel of the defective pixel A defect component calculating means for calculating a defect component of the signal;
The defective pixel output by the solid-state imaging device is obtained by subtracting the defective component of the pixel signal of the corresponding defective pixel calculated by the defective component calculating means from the pixel signal of the defective pixel at the address output by the solid-state imaging device. A defect component removing means for removing the defect component from the pixel signal of
An imaging apparatus characterized by that. A plurality of effective pixels arranged in a matrix that converts incident light into signal charges and outputs them as pixel signals;
A plurality of light shielding pixels arranged around the plurality of effective pixels so as to form a matrix together with the plurality of effective pixels and covered with a light shielding film;
Each of the plurality of effective pixels and the plurality of light shielding units includes at least one pixel transfer unit of an effective pixel transfer unit that extracts pixel signals of the plurality of effective pixels and a light shielding pixel transfer unit that extracts image signals of the plurality of light shielding pixels. An effective / light-shielding pixel unit having a plurality of effective / light-shielding pixel vertical transfer registers that extract pixel signals for each column of pixels and transfer them in the vertical direction;
One or a plurality of invalid pixel verticals arranged in a row or matrix around the effective / light-shielded pixel portion and transferring a pixel signal having a pixel value of 0 in the vertical direction to the valid / light-shielded pixel vertical transfer register A transfer register;
A correction method of a pixel signal for correcting a pixel signal output by an imaging device including a horizontal transfer register for transferring a pixel signal transferred by the plurality of effective / light-shielded pixel vertical transfer registers in a horizontal direction,
A defective pixel detection step of detecting a defective pixel of the solid-state image sensor based on a pixel signal output by the solid-state image sensor when the solid-state image sensor is operated in a light-shielded state;
When the solid-state image sensor is operated in a light-shielded state, the solid-state image sensor is transferred from the pixel signals of the plurality of light-shielded pixels extracted by the light-shielded pixel transfer unit and output by the solid-state image sensor, and transferred by the invalid pixel vertical transfer register. A first sensor-induced dark current calculation step of subtracting a pixel signal output by the element and calculating a sensor-induced dark current;
A ratio calculation step of calculating a ratio between a pixel signal of the defective pixel detected in the defective pixel detection step and a sensor-induced dark current calculated in the first sensor-induced dark current calculation step;
A defective pixel storage step for storing the address of the defective pixel detected in the defective pixel detection step and the ratio of the defective pixel corresponding to the address calculated in the ratio calculation step in association with each other;
The sensor signal is derived by subtracting the pixel signal transferred by the invalid pixel vertical transfer register and output by the solid-state image sensor from the pixel signals of the plurality of light-shielded pixels output by the light-shielded pixel transfer unit and output by the solid-state image sensor. A second sensor-derived dark current calculation step for calculating dark current;
The defective pixel address stored in the defective pixel storage step and the corresponding ratio are read out, the sensor-induced dark current calculated in the second sensor-derived dark current calculation step is multiplied by the ratio, and the pixel of the defective pixel A defect component calculation step for calculating a defect component of the signal;
The defective pixel output by the solid-state imaging device is obtained by subtracting the defective component of the pixel signal of the corresponding defective pixel calculated in the defective component calculation step from the pixel signal of the defective pixel at the address output by the solid-state imaging device. Removing a defect component from the pixel signal of the defect component,
A method for correcting a pixel signal.

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