JP2016167773A - Imaging apparatus and processing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging apparatus capable of reducing image shading caused by instability of voltage of a well, and reducing noises attributed to a well contact area, and a processing method of the same.SOLUTION: The imaging apparatus is disposed inside a well of a semiconductor substrate and includes: a plurality of pixels each having a photoelectric conversion part; a plurality of well contact areas for providing the wells of the semiconductor substrate with reference potential; and a signal processing part for correcting a signal of at least one pixel among the plurality of pixels neighboring the well contact areas.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an imaging apparatus and a processing method of the imaging apparatus.

  In recent years, CMOS type image sensors are mounted on digital cameras, digital video cameras, camera-equipped mobile phones, and the like. A CMOS image sensor includes a semiconductor substrate, a well formed in the semiconductor substrate, and a plurality of photodiodes arranged in a matrix in the well. Further, in order to fix and stabilize the potential of the well, there is known a CMOS type image pickup device including a well contact region for applying a reference potential in a region where a photodiode in the well is disposed.

  For example, Patent Document 1 discloses a configuration in which a well contact is provided for each of a plurality of pixels according to a periodic pattern. In the image sensor of Patent Document 1, the potential distribution of the well can be stabilized while minimizing the space for providing the well contact.

  In addition, the imaging element of Patent Document 2 includes a P-type well having a first impurity concentration formed in a semiconductor substrate, a plurality of N-type photodiodes arranged in a matrix in the P-type well, and a P-type well. Well contact. The P-type well contact is formed for each photodiode in the P-type well, and a reference potential having a second impurity concentration higher than the first impurity concentration is applied. Further, in the P-type well, a P-type dark charge trapping region having a third impurity concentration higher than the first impurity concentration and capturing charges due to dark current is formed in the vicinity of the well contact. According to the image sensor of Patent Document 2, it is possible to prevent the charge due to the dark current generated in the vicinity of the well contact from being mixed with the signal charge accumulated in the photodiode.

JP 2001-230400 A JP 2012-15160 A

  The configuration in which the well contact is provided in the pixel as in Patent Document 2 has a problem that the dark current charge generated in the vicinity of the well contact becomes a noise charge mixed with the signal charge, thereby degrading the image quality. If the well contacts are provided in all the pixels of the image sensor, the dynamic range or the SN ratio of the image sensor can be deteriorated. Therefore, it is preferable to dispose the well contacts discretely for each of the plurality of pixels so that the well potential can be sufficiently stabilized.

  However, in Patent Document 1 in which well contacts are provided for each of a plurality of pixels in accordance with a periodic pattern, the imaging conditions are such that the influence of dark current appears in an image, such as when setting high ISO sensitivity and when shooting with a long second exposure. In particular, a lot of noise charges are mixed in pixels around the well contact. This noise charge appears in the image according to the pattern of the pixel provided with the well contact, which causes a significant deterioration in image quality.

  An object of the present invention is to provide an imaging apparatus and a processing method of the imaging apparatus that can reduce image shading and noise caused by a well contact region due to unstable well potential.

  An imaging device of the present invention is provided in a well of a semiconductor substrate, each of which has a plurality of pixels each having a photoelectric conversion unit, a plurality of well contact regions for supplying a reference potential to the well of the semiconductor substrate, and imaging conditions And a signal processing unit that corrects a signal of at least one of the plurality of pixels adjacent to the well contact region.

  By providing the well contact region, the potential of the well can be stabilized and shading of the image can be reduced, and noise caused by the well contact region can be reduced by correcting the signal processing unit.

1 is a block diagram of an imaging apparatus according to a first embodiment of the present invention. It is a figure which shows the structure of the image pick-up element which concerns on the 1st Embodiment of this invention. It is a figure which shows the structure of the pixel which concerns on the 1st Embodiment of this invention. 1 is an equivalent circuit diagram of a pixel according to a first embodiment of the present invention. It is a flowchart which shows the imaging | photography process which concerns on the 1st Embodiment of this invention. It is a figure which shows a well contact pixel correction determination table. It is a figure which shows the structure of the pixel which concerns on the 1st Embodiment of this invention. It is a flowchart which shows the flow of a dark current level acquisition process. It is a flowchart which shows the flow of a well contact pixel correction process. It is a figure which shows a dark current correction value calculation coefficient table. It is a figure which shows the arrangement pattern of a well contact pixel. It is a flowchart which shows the flow of an imaging | photography process.

(First embodiment)
FIG. 1 is a block diagram illustrating a configuration example of an imaging apparatus according to the first embodiment of the present invention. The image sensor 101 receives an optical image formed by the optical system, and converts the optical image into an electrical signal. An analog front end (hereinafter referred to as AFE) 102 performs reference level adjustment (clamp processing) and analog-digital conversion processing on the output signal of the image sensor 101. Note that the AFE 102 may be provided in the image sensor 101. A digital front end (hereinafter referred to as DFE) 103 performs digital processing such as image signal correction and pixel rearrangement on the output signal of the AFE 102. The digital signal processing unit 104 performs development processing and defective pixel interpolation processing on the output signal of the DFE 103. The storage unit 105 is used as a working memory for the digital signal processing unit 104 or as a buffer memory for continuous shooting or the like. The storage unit 105 also stores defective pixel data such as defective pixel addresses and defect levels. The control unit 106 includes a CPU and the like, and comprehensively controls the entire imaging apparatus. The operation unit 107 outputs an electrical signal to the control unit 106 in accordance with a user operation. The display unit 108 displays various setting screens, images, and the like. The recording unit 109 records an image or the like on a recording medium such as a memory card or a hard disk. The timing generation circuit 110 generates a timing signal for driving the image sensor 101.

  FIG. 2 is a diagram illustrating a configuration example of the image sensor 101 of FIG. The image sensor 101 includes a pixel unit 201, a vertical scanning unit 202, a reading unit 203, and a horizontal scanning unit 204. The pixel unit 201 has a plurality of pixels arranged in a matrix in a well formed in a semiconductor substrate. The pixel unit 201 receives an optical image formed by the optical system. The pixel unit 201 includes an opening 205 including a plurality of pixels that output a pixel signal corresponding to the amount of received light, and an optical black unit (hereinafter referred to as an OB unit) 206 including a plurality of pixels in which the light receiving unit is shielded from light. Have. The OB portion 206 is a light shielding area where pixels are shielded from light. The opening 205 is an opening area where pixels are not shielded from light. Signals of a plurality of pixels in the OB unit 206 are used as a dark reference level for each captured image. The vertical scanning unit 202 sequentially selects a plurality of pixels in the pixel unit 201 in units of rows. The pixels in the selected row output a signal to the reading unit 203. The horizontal scanning unit 204 sequentially selects the column of pixels in the row read by the reading unit 203, and causes the AFE 102 to output a signal of the selected pixel from the reading unit 203. That is, the reading unit 203 reads the signal of the pixel selected by the vertical scanning unit 202 and the horizontal scanning unit 204 and outputs the read signal to the AFE 102. Thereby, the signals of all the pixels in the pixel unit 201 are output to the AFE 102.

  FIG. 3 is a diagram illustrating a configuration example of the four pixels 301 and 316 to 318 in the pixel unit 201 of FIG. For simplicity of explanation, only the four pixels 301 and 316 to 318 are shown, but in reality, more pixels are arranged. All the pixels in the pixel portion 201 are formed in the same well in the semiconductor substrate.

  The pixel 301 includes a photodiode 302 formed in a well of a semiconductor substrate, a floating diffusion (hereinafter referred to as FD) 303, diffusion regions 304 to 307, and a well contact region 308, each of which is an element isolation region 313. being surrounded. Further, four gate electrodes 309 to 312 are formed on the semiconductor substrate via an insulating film. The wiring 314 connects the FD 303, the gate electrode 311, and the diffusion region 307. A vertical output line (column output line) 315 is connected to the diffusion region 304 and is a signal line for outputting the signal of the pixel 301 to the reading unit 203 for each column. The vertical output line 315 is provided for each column of pixels, and the pixels in the same column are connected to the same vertical output line 315. The well contact region 308 is connected to a well in the semiconductor substrate.

  The pixels 316 to 318 are pixels in which the well contact region 308 is not disposed, but have other configurations similar to those of the pixel 301. Here, in the following description, a pixel in which the well contact region 308 is arranged like the pixel 301 is particularly referred to as a “well contact pixel”, and a pixel in which the well contact region 308 is not arranged like the pixels 316 to 318. Will be referred to as “ordinary pixels”.

  In the pixel unit 201, for example, one well contact pixel 301 is provided for three normal pixels 316 to 318. By disposing well contact pixels 301 in such a manner that the well potential can be sufficiently stabilized in the pixel portion 201, shading of a captured image can be reduced. However, the layout of each component in each pixel in FIG. 3 is not limited to the configuration in FIG. 3 and may be arranged at an appropriate position within a range where the function is exhibited.

  FIG. 4 is an equivalent circuit diagram of the pixel 301 in FIG. Although a configuration example of the pixel 301 is shown, the pixels 316 to 318 also have the same configuration. The photodiode 401 is a photoelectric conversion unit that receives incident light and generates and accumulates charges corresponding to the amount of received light. The photodiode 401 corresponds to the photodiode 302 in FIG.

  The transfer transistor 402 transfers the charge generated in the photodiode 401 to the FD 403 in response to the transfer pulse signal φTX. The FD 403 can hold the charge transferred from the photodiode 303 and corresponds to the FD 303 in FIG. The transfer transistor 402 corresponds to the photodiode 302, the FD 303, and the gate electrode 309 in FIG.

  The output transistor 404 amplifies a voltage based on the electric charge held in the FD 403 and outputs it as a pixel signal. Here, as an example, a source follower circuit using an output transistor (MOS transistor) 404 and a constant current source 407 is shown. The constant current source 407 is connected to the vertical output line 315. The output transistor 404 corresponds to the diffusion region 305, the diffusion region 306, and the gate electrode 311 in FIG.

  The selection transistor 405 outputs the signal output from the output unit 404 to the vertical output line 315 in response to the vertical selection pulse signal φSEL. As described above, the signal output to the vertical output line 315 is sampled by the readout unit 203 for each column, and then output to the AFE 102. The selection transistor 405 corresponds to the diffusion region 304, the diffusion region 305, and the gate electrode 310 in FIG.

  The reset transistor 406 supplies the reference potential SVDD to the FD 403 in response to the reset pulse signal φRES, and resets the charge of the FD 403. The reset transistor 406 corresponds to the diffusion region 306, the diffusion region 307, and the gate electrode 312 in FIG.

  The well 408 is provided in the semiconductor substrate and is a common well for all pixels. For example, a p-type well 408 is provided in an n-type semiconductor substrate. The anode of the photodiode 401 and the FD 403 are connected to the well 408. The back gates of the transfer transistor 402, the output transistor 404, the selection transistor 405, and the reset transistor 406 are connected to the well 408. The well contact region 308 is connected to the well 408. A ground potential (reference potential) is applied to the well contact region 308. The well contact region 308 supplies a ground potential to the well 408. The well contact pixel 301 is provided with the well contact region 308, but the normal pixels 316 to 318 are not provided with the well contact region 308. That is, the normal pixels 316 to 318 are different from the well contact pixel 301 only in that there is no well contact region 308. The pixel unit 201 includes a plurality of well contact pixels 301 and a plurality of normal pixels 316 to 318 at a ratio of 1: 3, for example. Each of the plurality of well contact pixels 301 has a plurality of well contact regions 308. The number of the plurality of well contact regions 308 is smaller than the number of the plurality of pixels 301 and 316 to 318. By applying a ground potential to the well contact region 308 in the plurality of well contact pixels 301, variations in the potential of the well 408 (back gate potentials of the transistors 402 and 404 to 406) from pixel to pixel are reduced. Thereby, shading of the image is reduced and the image quality can be improved.

  Here, when the well contact region 308 is provided in the well contact pixel 301, the dark current charge generated in the vicinity of the well contact region 308 is mixed with the signal charge as noise, and the image quality is deteriorated. Therefore, when the well contact region 308 is provided in all the pixels of the pixel portion 201, the dynamic range or the SN ratio of the imaging device can be deteriorated. Therefore, it is preferable that the well contact pixels 301 are discretely arranged in the pixel portion 201 and the other pixels are normal pixels 316 to 318 so that the potential of the well 408 can be sufficiently stabilized.

  Also, under imaging conditions where the influence of dark current often appears in an image, such as when setting high ISO sensitivity or shooting with a long second exposure under a high temperature environment, noise charge is particularly included in the signal charge of the well contact pixel 301 having the well contact region 308. Are mixed together and cause image quality degradation. Hereinafter, a method for improving the image quality by correcting the signal of the well contact pixel 301 in order to remove the noise will be described with reference to FIG.

  FIG. 5 is a flowchart illustrating a processing method of the imaging apparatus of FIG. In step S501, when the control unit 106 determines that the shooting process should be started, the control unit 106 sets shooting conditions set by the user, such as ISO sensitivity and shutter speed. Next, in step S502, the control unit 106 drives the image sensor 101 under the imaging conditions set in step S501 via the timing generation circuit 110, and causes the image sensor 101 to output an image signal. Next, in step S503, the control unit 106 determines whether or not correction processing is necessary for the well contact pixel 301 in accordance with the set imaging condition. In the determination, it is determined that correction processing is necessary when the dark current component in the image signal is increased. An example will be described with reference to FIG.

  FIG. 6 is a diagram showing a well contact pixel correction determination table. The control unit 106 determines that the correction is necessary when the shooting condition is that the shutter speed is 1 second or more and the ISO sensitivity is ISO 3200 or more, and the correction is performed when the shooting condition is other than that. Determine that it is not necessary. The configuration of the correction determination table is not limited to this, and for example, it may be determined whether correction processing is necessary with reference to the temperature of the image sensor 101. In order to acquire the temperature of the image sensor 101, a thermometer may be provided inside the image sensor 101. Further, a thermometer can be arranged on the mounting substrate of the image sensor 101 and used. The shooting conditions determined to require correction may be set appropriately according to the characteristics of the image sensor 101.

  If it is determined in step S503 that correction is necessary, the process proceeds to step S504. If it is determined that correction is not necessary, the process proceeds to step S505. In step S <b> 504, the digital signal processing unit 104 performs a correction process for the well contact pixel 301. The correction processing method includes a method of interpolating the signal of the well contact pixel 301 to be corrected with the average value of the signals of a plurality of pixels of the same color around the well contact pixel 301. The well contact pixel 301 is a pixel having the photodiode 302 closest to the well contact region 308 among the photodiodes 302 of the plurality of pixels 301 and 316 to 318 having the photodiode 302 adjacent to the well contact region 308. In step S504, the digital signal processing unit 104 corrects the signal of the pixel 301 having the photodiode 302 closest to the well contact region 308 according to the imaging condition. Thereafter, the process proceeds to step S505.

  In step S505, the digital signal processing unit 104 performs defective pixel correction processing, white balance processing, and development processing of the image sensor 101. In step S506, the control unit 106 displays the developed photographed image on the display unit 108, records it in the recording unit 109, and ends the photographing process.

  As described above, according to the present embodiment, the shading of the captured image can be reduced by disposing the well contact pixels 301 in the pixel unit 201 in a discrete manner. Further, under imaging conditions in which the dark current component in the image signal increases, the image quality deterioration due to noise charges generated in the vicinity of the well contact pixel 301 can be reduced by correcting (interpolating) the signal of the well contact pixel 301. it can.

  In FIG. 5, the pixel to be corrected is the well contact pixel 301 in which the well contact region 308 is arranged, but a plurality of pixels adjacent to one well contact pixel 301 may be corrected. . The distance between the well contact region 308 and the photodiode 302 is closely related to the influence of noise charges on the image signal. For example, as shown in FIG. 7, the case of four pixels in which photodiodes 701 to 704 and a well contact region 705 are arranged will be described as an example. In this case, a pixel to be corrected may be selected according to the distance between the well contact region 705 and the photodiodes 701 to 704 adjacent thereto. For example, two pixels including a photodiode 701 and a photodiode 704 that are close to the well contact region 705 can be corrected. In step S <b> 504, the digital signal processing unit 104 corrects the signal of at least one pixel among the plurality of pixels having the plurality of photodiodes 701 to 704 adjacent to the well contact region 705 according to the imaging condition. Good.

  Note that when applying correction processing by interpolation to pixel signals of a plurality of adjacent pixels, it is necessary to be careful because a trace that has been subjected to interpolation processing called correction trace is likely to appear in an image. In the second embodiment described below, an embodiment in which such a correction mark hardly appears in an image will be described.

(Second Embodiment)
The second embodiment of the present invention is different from the first embodiment in the correction processing method of the well contact pixel 301. The imaging device according to the present embodiment acquires a noise charge generation level due to the dark current of the well contact pixel 301 in advance in the manufacturing process of the imaging device. Hereinafter, the points of the present embodiment different from the first embodiment will be described.

  FIG. 8 is a flowchart showing dark current level acquisition processing of the well contact pixel 301 performed in the manufacturing process of the imaging device of the present embodiment. In step S801, the control unit 106 sets shooting conditions for obtaining an image for acquiring a dark current level. This shooting condition is set under conditions where dark current is likely to occur. For example, the shooting speed is set at a shutter speed of 4 seconds and ISO sensitivity of ISO 12800. In addition, it is desirable that the temperature environment at the time of shooting is appropriately managed, and for example, shooting is performed under an environment of 30 ° C.

  Next, in step S <b> 802, the control unit 106 drives the image sensor 101 under the shooting conditions set in step S <b> 801 and in a light-shielded state via the timing generation circuit 110, and outputs a dark image signal to the image sensor 101. Let The light shielding state is a state where the pixels are shielded from light.

  In step S803, the digital signal processing unit 104 extracts a pixel signal of the well contact pixel 301 from the dark image signal. In step S804, the digital signal processing unit 104 records the dark pixel signal for each address of the well contact pixel 301 in the storage unit 105 as a dark current level (correction data).

  The above is the dark current level acquisition processing of the well contact pixel 301 performed in the manufacturing process of the imaging device. Note that the dark current level acquisition process described above is not limited to the manufacturing process of the imaging device, and may be performed, for example, in an inspection process when manufacturing the imaging device 101. For example, when the image sensor 101 is in a light-shielded state after shipment of the image capturing apparatus, the image sensor 101 may be automatically executed in the background.

  Next, the flow of shooting processing by the imaging apparatus of this embodiment will be described. In the present embodiment, imaging processing is performed in the same manner as in FIG. 5 of the first embodiment. However, this embodiment is different from the first embodiment in the processing method of well contact pixel correction in step S504. Hereinafter, the processing method of step S504 in the present embodiment will be described. In the first embodiment, the method of interpolating the pixel signal of the well contact pixel 301 with the average value of the surrounding pixels of the same color for each pixel when it is determined that correction is necessary has been described. In the present embodiment, in step S504 of FIG. 5, processing is performed according to the flowchart of FIG.

  In FIG. 9, the signal of the well contact pixel 301 in which the well contact region 308 is arranged is corrected using the dark current level (correction data) stored in the storage unit 107. The conditions for acquiring the dark current level were a shutter speed of 4 seconds and an ISO sensitivity of ISO 12800 in a 30 ° C. environment. Therefore, in the correction, a value obtained by multiplying the dark current level by a coefficient corresponding to the temperature of the image sensor 101, the shutter speed, and the ISO sensitivity is used as the offset correction value every time shooting is performed.

  In step S901 in FIG. 9, the control unit 106 acquires the temperature, shutter speed, and ISO sensitivity of the image sensor 101 as imaging conditions. Next, in step S902, the digital signal processing unit 104 sets the coefficient A in FIG. 10A corresponding to the imaging condition to the dark current correction level stored in the storage unit 105 for each of the plurality of well contact pixels 301. And the coefficient B in FIG. Thereby, the dark current correction value for each well contact pixel 301 of interest is calculated.

  FIGS. 10A and 10B show coefficients A and B that are multiplied by the dark current level according to the shooting conditions. FIG. 10A is a table showing a coefficient A determined by the shutter speed and ISO sensitivity. FIG. 10B is a table showing a coefficient B determined by the temperature of the image sensor 101. These tables are generated according to the characteristics of the image sensor 101. Further, these tables can be recorded in the storage unit 105 in advance.

  In step S903, the digital signal processing unit 104 corrects the pixel signal by subtracting the dark current correction value for each well contact pixel 301 obtained in step S902 from the pixel signal for each well contact pixel 301. To do.

  As described above, in the present embodiment, shading of a captured image can be reduced by disposing well contact pixels 301 in the pixel unit 201 similarly to the first embodiment. Furthermore, under imaging conditions in which the dark current component in the image signal increases, image quality degradation due to noise charges generated in the vicinity of the well contact region 308 can be reduced by correcting the signal of the well contact pixel 301.

  Also in this embodiment, the pixel to be corrected is the well contact pixel 301 in which the well contact region 308 is arranged, but the plurality of normal pixels 316 and 317 adjacent to one well contact pixel 301 of interest are also Similarly, correction processing may be performed. In this case, in step S804 in FIG. 8, the dark pixel signal level is set as the dark current level for each address of the well contact pixel 301 and the plurality of normal pixels 316 and 317 adjacent to the well contact pixel 301. 105. Then, in step S902 of FIG. 9, the dark current correction value can be calculated by multiplying the dark current level for each pixel by the coefficient A and the coefficient B. Alternatively, in this case, in step S902 of FIG. 9, the dark current correction value is determined based on the dark current correction value of the well contact pixel 301 according to the distance from the well contact region 308 to the photodiode 302 of the normal pixels 316 and 317. You may calculate by converting. In contrast to the first embodiment, since the pixel signal is corrected by offset correction, the present embodiment is advantageous in that correction traces are unlikely to appear in an image.

(Third embodiment)
In the third embodiment of the present invention, the dark current charge of the well contact pixel is corrected by the horizontal OB clamping process (horizontal optical black clamping process) of the DFE (signal processing unit) 103. FIG. 11 is a diagram illustrating a relationship between the pixel unit 201 and the output channel of the image sensor 101 in the present embodiment. In the present embodiment, an example in which the image sensor 101 outputs an image signal with four channels and the DFE 103 performs horizontal OB clamping processing for each channel and for each even-numbered row and every odd-numbered row is shown. In FIG. 11, the pixel portion 201 has pixels of 5 rows and 9 columns, but is not limited thereto. The first channel outputs signals of pixels in the first column, the fifth column, and the ninth column. The second channel outputs the signals of the pixels in the second column and the sixth column. The third channel outputs the signals of the pixels in the third and seventh columns. The fourth channel outputs the signals of the pixels in the fourth column and the eighth column.

  In the pixel unit 201, well contact pixels 1101 to 1104 are discretely arranged according to a group of pixels to be subjected to horizontal OB clamping processing. Alphabets A, B, C, D, E, F, G, and H attached to the pixels indicate groups in which the DFE 103 performs horizontal OB clamping processing. Here, each pixel to which F is attached is the well contact pixels 1101 to 1104, and the other pixels are normal pixels. The well contact pixels 1101 to 1104 have the same configuration as the well contact pixel 301 in FIG. 3 and have a well contact region 308. A normal pixel does not have a well contact region 308. Further, the well contact pixel and the normal pixel are arranged in the opening portion 205 and the OB portion 206 of the pixel portion 201 in accordance with the same periodic pattern. That is, the well contact region is periodically provided for the pixel in the opening 205 and the OB portion 206.

  The horizontal OB clamping process is performed so that the difference between the pixel signal of the pixel in the OB portion 206 of each row and the black level reference value is reduced for each channel and for each even row and odd row. Offset correction is performed on the pixel signal. With the horizontal OB clamping process, the dark reference level of the well contact pixel in the opening 205 is adjusted based on the well contact pixel in the OB portion 206. Therefore, according to the present embodiment, noise associated with the dark current charge of the well contact pixel is reduced, and good image quality can be obtained.

  FIG. 12 is a flowchart showing a flow of shooting processing by the imaging apparatus of the present embodiment. In step S1201, when the control unit 106 determines that the shooting process should be started, the control unit 106 sets shooting conditions set by the user, such as ISO sensitivity and shutter speed. Next, in step S1202, the control unit 106 drives the image sensor 101 under the imaging conditions set in step S1201 via the timing generation circuit 110, and causes the image sensor 101 to output an image signal.

  Next, in step S1203, the DFE 103 performs a horizontal OB clamping process on the image signal. The horizontal OB clamping process is performed so that the difference between the image signal of the pixel in the OB portion 206 of each row and the black level reference value is reduced for each channel and for each even row and odd row. Offset correction is performed on the pixel signal. That is, the DFE (signal processing unit) 103 periodically performs horizontal OB clamping processing on the pixels of the opening 205 using the pixel signal of the OB unit 206 as a reference level.

  Next, in step S1204, the digital signal processing unit 104 performs defective pixel correction processing, white balance processing, and development processing of the image sensor 101. In step S1205, the control unit 106 displays the developed photographed image on the display unit 108, records it in the recording unit 109, and ends the photographing process.

  As described above, in the present embodiment, as in the first embodiment, shading of a captured image can be reduced by disposing well contact pixels in the pixel unit 201 in a discrete manner. Furthermore, by performing the horizontal OB clamping process according to the period of the well contact pixels arranged in the opening 205 and the OB part 206, it is possible to reduce image quality deterioration due to noise charges generated in the vicinity of the well contact region.

  The above-described embodiments are merely examples of implementation in carrying out the present invention, and the technical scope of the present invention should not be construed in a limited manner. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

101 Image sensor, 102 AFE, 103 DFE, 104 Digital signal processing unit, 201 pixel unit, 205 opening, 206 OB unit, 301 well contact pixel, 302 photodiode, 308 well contact region, 316 to 318 normal pixel

Claims (11)

A plurality of pixels provided in a well of a semiconductor substrate, each having a photoelectric conversion unit;
A plurality of well contact regions for supplying a reference potential to the well of the semiconductor substrate;
An image pickup apparatus comprising: a signal processing unit that corrects a signal of at least one pixel among a plurality of pixels adjacent to the well contact region according to a photographing condition.   The imaging device according to claim 1, wherein the number of the plurality of well contact regions is smaller than the number of the plurality of pixels.   The imaging apparatus according to claim 1, wherein the imaging condition includes at least one of shutter speed, ISO sensitivity, and temperature.   The signal processing unit corrects a signal of the pixel to be corrected using signals of the plurality of pixels around the pixel to be corrected. The imaging device described.   The image pickup apparatus according to claim 1, wherein the signal processing unit corrects the signal of the pixel using correction data stored in a storage unit.   The imaging apparatus according to claim 5, wherein the correction data is data based on a signal of the pixel in a state where the pixel is shielded from light.   The imaging apparatus according to claim 1, wherein the signal processing unit corrects a signal of a pixel having the photoelectric conversion unit closest to the well contact region. The number of the plurality of well contact regions is less than the number of the plurality of pixels,
The plurality of pixels are arranged in a matrix and include a plurality of pixels in a light-shielding region that is shielded from light and a plurality of pixels in an opening region that is not shielded from light.
The imaging device according to claim 1, wherein the well contact region is periodically provided with respect to the pixel in the light shielding region and the opening region.   9. The imaging apparatus according to claim 8, wherein the signal processing unit periodically performs an optical black clamp process on the pixels in the aperture region using a signal of the pixel in the light shielding region as a reference level.   The imaging apparatus according to claim 9, wherein the signal processing unit performs an optical black clamp process according to a cycle of a pixel in which the well contact region is provided. A plurality of pixels provided in a well of a semiconductor substrate, each having a photoelectric conversion unit;
A processing method of an imaging device having a plurality of well contact regions for supplying a reference potential to a well of the semiconductor substrate,
A processing method of an imaging apparatus, comprising: a step of correcting a signal of at least one pixel among a plurality of pixels adjacent to the well contact region by a signal processing unit according to an imaging condition.

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