Imaging device, imaging device control method, and imaging device control program

Abstract

An imaging device according to the present invention is provided with a plurality of pixel rows, an error detection unit, and a failure determination unit. The plurality of pixel rows constitute a pixel array in which pixels comprising CMOS are arranged, and each pixel row is configured by connecting, via wiring, imaging pixels that output pixel signals corresponding to incident light, a row-specific value reference pixel that outputs a row-specific reference signal, and a correction code reference pixel that outputs an error correction code for the reference signal. On the basis of the reference signal output from the row-specific value reference pixel constituting a specific pixel row among the plurality of pixel rows and the error correction code output from the correction code reference pixel constituting the pixel row, the error detection unit detects an error in the reference signal. The failure determination unit determines whether or not a failure has occurred in the pixel row on the basis of the reference signal and the result of detection by the error detection unit.

Description

Image capture device, image capture device control method, and image capture device control program

[0001] The present technology relates to an imaging device including a CMOS (Complementary Metal Oxide Semiconductor) image sensor, an imaging device control method, and an imaging device control program.

[0002] In a typical CMOS image sensor, the row scanning unit outputs pixel control signals such as reset, accumulation, and transfer for the intended pixels in the pixel array, and selects the address of the row to be read out, and the pixel signals output from the pixel array are converted into digital data by a column-parallel analog-to-digital converter. Therefore, if an accidental failure occurs in the row scanning unit or the pixel control signal wiring output from the row scanning unit, incorrect pixel control or incorrect readout row selection will occur, causing abnormalities in the image data captured by the image sensor. The function of detecting whether the image sensor performed pixel control and readout row selection as intended is particularly useful for camera systems equipped with image sensors.

[0003] Conventionally, as a method for detecting a failure in a row scanning unit or a pixel control signal wiring output from the row scanning unit, there has been an example in which a row-specific potential is applied to a reference pixel arranged in the same row as an imaging pixel in a pixel array, the reference pixel is read out simultaneously with the imaging pixel, and row-specific digital data converted by a column-parallel AD (Analog to Digital) conversion circuit is used to compare the row-specific digital data with an expected value for the intended readout row.

[0004] For example, in Patent Document 1 listed below, row-specific binary data is created by combining two potentials input to a reference pixel from outside the pixel array for each row, and this reference pixel digital data is compared with an expected value to detect a fault. This technology can detect faults in the row scanning unit and the pixel control signal wiring output from the row scanning unit.

[0005] As another example, Patent Document 2 is similar to Patent Document 1 in that reference pixels are given row-specific binary data and the digital data of the reference pixels is compared with an expected value to detect a fault, but it also discloses a technology in which the presence or absence of a fault in the reference pixel is stored in advance in a memory within the image sensor or input from outside the image sensor.

[0006] With this technology, before comparing the digital data of the reference pixel with the expected value, the accuracy of the detection of a fault due to a fault in the reference pixel is determined based on the presence or absence of the fault. As a result, an image sensor in which the row scanning unit and the pixel control signal wiring output from the row scanning unit are normal and only the reference pixel has experienced an initial fault can be considered normal.

[0007] JP 2018-56962 A JP 2018-61234 A

[0008] However, in the technology described in Patent Document 1, failures in reference pixels are also subject to failure detection, so an image sensor in which the row scanning unit and the pixel control signal wiring output from the row scanning unit are normal and only the reference pixel has a failure is deemed to have an abnormality in the row scanning unit and the pixel control signal wiring output from the row scanning unit, which will result in a decrease in yield if it is an initial failure, or excessive failure detection if it is an accidental failure.

[0009] In order to avoid the influence of a reference pixel failure in this method, it is conceivable to arrange multiple reference pixels having the same row-specific data in the same row and add comparison between the reference pixels, but this would increase the area of ​​the image sensor.Furthermore, the technology described in Patent Document 2 above requires an information storage mechanism to be installed inside or outside the image sensor for storing information on the success or failure of failure detection due to a reference pixel failure.

[0010] In view of the above circumstances, an object of the present technology is to provide an imaging device, an imaging device control method, and an imaging device control program that are highly efficient and capable of accurate failure detection.

[0011] To achieve the above object, an imaging device according to one embodiment of the present technology includes a plurality of pixel rows, an error detection unit, and a fault determination unit. The plurality of pixel rows form a pixel array in which pixels formed by CMOS (Complementary Metal Oxide Semiconductor) are arranged, and each pixel row is configured by wiring connecting imaging pixels that output pixel signals corresponding to incident light, row-specific value reference pixels that output row-specific reference signals, and correction code reference pixels that output error correction codes for the reference signals. The error detection unit detects an error in the reference signal based on the reference signal output from the row-specific value reference pixels constituting a specific pixel row among the plurality of pixel rows and the error correction code output from the correction code reference pixels constituting the pixel row. The fault determination unit determines whether or not a fault exists in the pixel row based on an illumination signal and a detection result by the error detection unit.

[0012] When the error detection unit does not detect an error in the reference signal output from the row-specific value reference pixel that constitutes the pixel row, the error detection unit may supply the reference signal to the fault detection and determination unit as the reference signal for the pixel row, and when the error detection unit detects an error in the reference signal output from the row-specific value reference pixel that constitutes the pixel row, the error detection unit may supply a reference signal obtained by correcting the reference signal as the reference signal for the pixel row to the fault determination unit.

[0013] The fault determination unit may compare the reference signal supplied from the error detection unit with an expected value set for the pixel row, and if the reference signal and the expected value do not match, determine that there is a fault in the pixel row.

[0014] When it is determined that the pixel row has a failure, the failure determination section may notify that an abnormality exists in a captured image generated based on outputs from the imaging pixels.

[0015] When the error detection unit detects an error in the reference signals output from the row-specific value reference pixels that constitute the pixel row, the failure determination unit may not need to determine whether or not there is a failure in the pixel row.

[0016] The error detection unit may detect an error in a reference signal output from row-specific value reference pixels that constitute the pixel row, and if the reference signal cannot be corrected, may notify that there is an abnormality in the captured image generated based on the output of the imaging pixels.

[0017] The plurality of pixel rows may include a first pixel row and a second pixel row that are read out simultaneously and have the same reference signal and error correction code; the error detection unit may detect an error in the first reference signal based on a first reference signal output from row-specific value reference pixels that constitute the first pixel row and a first error correction code output from correction code reference pixels that constitute the first pixel row, and when an error is detected from the first reference signal, detect an error in the second reference signal based on a second reference signal output from row-specific value reference pixels that constitute the second pixel row and a second error correction code output from correction code reference pixels that constitute the second pixel row; and the fault determination unit may determine the presence or absence of a fault in the first pixel row and the second pixel row based on the first reference signal, the second reference signal, and a detection result by the error detection unit.

[0018] When the error detection unit does not detect an error in a first reference signal output from the row-eigenvalue reference pixels constituting the first pixel row, it may supply the first reference signal to the fault determination unit as a reference signal for the first pixel row and the second pixel row; when the error detection unit detects an error in the first reference signal output from the row-eigenvalue reference pixels constituting the first pixel row and does not detect an error in a second reference signal output from the row-eigenvalue reference pixels constituting the second pixel row, it may supply the second reference signal to the fault determination unit as a reference signal for the first pixel row and the second pixel row.

[0019] The fault determination unit may compare the reference signal supplied from the error detection unit with an expected value set for the first pixel row and the second pixel row, and if the reference signal and the expected value do not match, determine that there is a fault in the first pixel row and the second pixel row.

[0020] When it is determined that there is a failure in the first pixel row and the second pixel row, the failure determination unit may notify that there is an abnormality in a captured image generated based on the output of the imaging pixels.

[0021] When the error detection unit detects an error in both a first reference signal output from the row-specific value reference pixels constituting the first pixel row and a second reference signal output from the row-specific value reference pixels constituting the second pixel row, the fault determination unit may not need to determine whether or not there is a fault in the first pixel row and the second pixel row.

[0022] When the error correction unit detects an error in both a first reference signal output from the row-specific value reference pixels constituting the first pixel row and a second reference signal output from the row-specific value reference pixels constituting the second pixel row, the error correction unit may notify that there is an abnormality in the captured image generated based on the output of the capturing pixels.

[0023] To achieve the above object, an imaging device control program according to one embodiment of the present technology operates an information processing device as an error detection unit and a fault determination unit. The error detection unit configures a pixel array in which pixels made of CMOS (Complementary Metal Oxide Semiconductor) are arranged, and each pixel row is configured by connecting imaging pixels that output pixel signals corresponding to incident light, row-specific value reference pixels that output row-specific reference signals, and correction code reference pixels that output error correction codes for the reference signals via wiring. The error detection unit detects an error in the reference signal based on a reference signal output from the row-specific value reference pixels constituting a specific pixel row and an error correction code output from the correction code reference pixels constituting the pixel row. The fault determination unit determines whether or not there is a fault in the pixel row based on the reference signal and a detection result by the error detection unit.

[0024] To achieve the above object, an imaging device control method according to one embodiment of the present technology includes an error detection unit that detects an error in a reference signal based on a reference signal output from the row-specific value reference pixel that constitutes a specific pixel row and an error correction code output from the correction code reference pixel that constitutes the pixel row, among a plurality of pixel rows that constitute a pixel array in which pixels made of CMOS (Complementary Metal Oxide Semiconductor) are arranged, and each pixel row is constituted by imaging pixels that output pixel signals corresponding to incident light, row-specific value reference pixels that output row-specific reference signals, and correction code reference pixels that output error correction codes for the reference signals, and the error detection unit detects an error in the reference signal based on a reference signal output from the row-specific value reference pixel that constitutes the specific pixel row and an error correction code output from the correction code reference pixel that constitutes the specific pixel row, and a failure determination unit that determines whether or not there is a failure in the specific pixel row based on the reference signal and a detection result by the error detection unit.

[0025] FIG. 1 is a schematic diagram of an imaging device according to a first embodiment of the present technology. FIG. 2 is a flowchart showing the operation of the imaging device. FIG. 3 is a schematic diagram of reference signals output by row eigenvalue reference pixels of the imaging device. FIG. 4 is a schematic diagram of a pixel array in a conventional imaging device. FIG. 5 is a schematic diagram of an imaging device according to a second embodiment of the present technology. FIG. 6 is a flowchart showing the operation of the imaging device. FIG. 7 is a block diagram showing the hardware configuration of an information processing device capable of realizing the functional configurations of the imaging devices according to the first and second embodiments of the present technology.

[0026] First Embodiment A first embodiment of the present technology will be described.

[0027] [Configuration and Operation of Imaging Device] Fig. 1 is a block diagram of an imaging device 100 according to a first embodiment. Fig. 2 is a flowchart showing the operation of the imaging device 100. As shown in Fig. 1, the imaging device 100 includes a pixel array 101, an A / D converter array 102, a row scanning unit 103, a control unit 104, a signal processing unit 105, a voltage supply unit 106, a ramp signal supply unit 107, an error detection unit 108, and a failure determination unit 109.

[0028] The pixel array 101 is an array in which pixels made of CMOS (Complementary Metal Oxide Semiconductor) are arranged. Specifically, the pixel array 101 includes imaging pixels 121, row eigenvalue reference pixels 122, and correction code reference pixels 123. In Fig. 1 , the row eigenvalue reference pixels 122 are indicated by hatching with diagonal lines, and the correction code reference pixels 123 are indicated by hatching with dots.

[0029] The pixel array 101 is composed of rows and columns of pixels. FIG. 1 shows pixel rows R and pixel columns L each composed of pixels. As shown in the figure, the pixel array 101 is composed of a plurality of pixel rows R and a plurality of pixel columns L. Each pixel row R is composed of one or more imaging pixels 121, row-specific value reference pixels 122, and correction code reference pixels 123. The pixels constituting each pixel row R are connected to each other by row wiring 131, and the pixels constituting each pixel column L are connected to each other by column wiring 132. The number of pixel rows R and pixel columns L constituting the pixel array 101 is not particularly limited.

[0030] The imaging pixels 121 photoelectrically convert incident light and accumulate electric charges. When a row selection signal is input from a row wiring 131, the imaging pixels 121 output a pixel signal corresponding to the amount of accumulated electric charge to a column wiring 132. The number of imaging pixels 121 constituting each pixel row R and each pixel column L is not particularly limited.

[0031] The row-specific value reference pixel 122 outputs a row-specific reference signal. The row-specific value reference pixel 122 receives a fixed voltage V ０ or V １ is supplied, and when a row selection signal is input from the row wiring 131, a fixed voltage V ０ and V １ A reference signal is output according to either of the fixed voltages V ０ The reference signal output from the row-specific value reference pixel 122 to which the fixed voltage V １ The reference signal output from the row eigenvalue reference pixel 122 to which the input signal is supplied is set to "1."

[0032] 1 shows only one row-specific value reference pixel 122 in each pixel row R, but in reality, a number of row-specific value reference pixels 122 are arranged that are sufficient to generate a reference signal specific to each pixel row R. FIG. 3 is a schematic diagram showing reference signals specific to each pixel row R. As shown in the figure, when pixel rows R have four rows, four different reference signals, "00," "01," "10," and "11," are generated by using two row-specific value reference pixels 122.

[0033] Therefore, by configuring each pixel row R with two row-specific value reference pixels 122, a reference signal specific to each pixel row R is generated. For example, if the number of pixel rows R is 1536, then １０ <1536<2 １１ Therefore, by setting the number of row-specific value reference pixels 122 constituting each pixel row R to 11, a reference signal specific to each pixel row R can be generated.

[0034] The correction code reference pixels 123 output an error correction code for the reference signal output by the row eigenvalue reference pixels 122. The type of error correction code is not particularly limited, and may be a parity code, a checksum, a cyclic redundancy check (CRC), a Hamming code, or the like. Although only one correction code reference pixel 123 is shown in each pixel row R in FIG. 1 , in reality, a number of correction code reference pixels 123 are arranged that is sufficient to generate an error correction code for the reference signal of each pixel row R. For example, if each pixel row R includes 11 row eigenvalue reference pixels 122 and the error correction code type is CRC-4, an error correction code can be generated by setting the number of correction code reference pixels 123 in each pixel row R to five.

[0035] The A / D converter array 102 is an array in which A / D converters 141 are arranged. The A / D converters 141 are connected to the column wirings 132, and convert analog signals input from the column wirings 132, specifically, pixel signals, reference signals, and error correction codes, into digital signals.

[0036] The row scanning unit 103 selects a pixel row R from which to read out a signal. When the row scanning unit 103 applies a voltage to the row wiring 131 of the pixel row R from which to read out, signals are output from the imaging pixels 121, row eigenvalue reference pixels 122, and correction code reference pixels 123 connected to this row wiring 131 to the column wiring 132 connected to each of them, and then read out. The row scanning unit 103 sequentially selects the pixel rows R from which to read out.

[0037] The control unit 104 is connected to and controls the row scanning unit 103 and the A / D converter 141. The signal processing unit 105 is connected to the imaging pixels 121 and the A / D converter 141 via column wiring 132, and generates image data based on pixel signals output from the imaging pixels 121. The voltage supply unit 106 supplies reference potentials for generating reference signals and error correction codes to the row eigenvalue reference pixels 122 and the correction code reference pixels 123. The ramp signal supply unit 107 supplies a ramp signal for A / D conversion to the A / D converter 141.

[0038] The error detection unit 108 detects an error in the reference signal based on the reference signal output from the row-specific value reference pixels 122 that constitute a specific pixel row R and the error correction code output from the correction code reference pixels 123 that constitute that pixel row R. Specifically, the error detection unit 108 reads out the reference signal output from the row-specific value reference pixels 122 that constitute the pixel row R selected by the row scanning unit 103 (St101, see FIG. 2 ).

[0039] Furthermore, the error detection unit 108 performs an error detection process using the error correction code output from the correction code reference pixels 123 that constitute the pixel row R, and detects an error in the reference signal output from the row eigenvalue reference pixels 122 (St102). The error in the reference signal is due to a failure in the row eigenvalue reference pixels 122.

[0040] When the error detection unit 108 does not detect an error in the reference signal output from the row-specific value reference pixels 122 that make up the pixel row R (St103; No), the error detection unit 108 supplies this reference signal to the failure determination unit 109 as the reference signal for the pixel row R. On the other hand, when the error detection unit 108 detects an error in the reference signal output from the row-specific value reference pixels 122 that make up the pixel row R (St103; Yes), the error detection unit 108 corrects this reference signal by error correction processing using an error correction code.

[0041] If the error detection unit 108 can correct the reference signal (St104; Yes), it corrects the reference signal (St105) and supplies the corrected reference signal to the fault determination unit 109 as the reference signal for the pixel row R. If the error detection unit 108 cannot correct the reference signal (St104; No), it notifies the outside, for example, the device in which the imaging device 100 is installed, that there is an abnormality in the captured image generated based on the output of the imaging pixels 121 (St106), and ends imaging.

[0042] The fault determination unit 109 determines whether or not a fault exists in the pixel row R based on the reference signal and the determination result by the error detection unit 108. Specifically, if the error detection unit 108 detects no error in the reference signals output from the row-specific value reference pixels 122 that constitute the pixel row R (St103; No), the fault determination unit 109 compares the reference signal supplied from the error detection unit 108 with an expected value that is set in advance for the pixel row R (St107). If the two values ​​match (St108; Yes), the fault determination unit 109 determines that no fault has occurred in the pixel row R. On the other hand, if the two values ​​do not match (St108; No), the fault determination unit 109 determines that a fault has occurred in the pixel row R.

[0043] If the reference signal does not match the expected value set for that pixel row R (St108; No), it is estimated that there is an abnormality in row scanning by the row scanning unit 103, a failure in the imaging pixels 121 that make up that pixel row R, or a failure in the row wiring 131 that makes up that pixel row R. Therefore, the failure determination unit 109 notifies the outside that there is an abnormality in the captured image generated based on the output of the imaging pixels 121 (St106), and terminates imaging. If the reference signal matches the expected value set for that pixel row R (St108; Yes), there is no abnormality in that pixel row R, so imaging continues.

[0044] On the other hand, if the error detection unit 108 detects an error in the reference signal output from the row-specific value reference pixels 122 that constitute pixel row R (St103; Yes) and the error is not corrected by the error detection unit 108 (St104; No), the failure determination unit 109 does not determine whether or not there is a failure due to the reference signal. If there is an error in the reference signal, it is estimated that a failure has occurred in the row-specific value reference pixels 122. Therefore, if failure determination is performed, it will be determined that a failure has occurred in pixel row R, even if no failure has occurred in pixels other than the row-specific value reference pixels 122 of pixel row R. By not performing failure determination by the failure determination unit 109, it is possible to prevent failure determination due to a failure in the row-specific value reference pixels 122.

[0045] Furthermore, if the error detection unit 108 detects an error in the reference signals output from the row-specific value reference pixels 122 that constitute a pixel row R (St103; Yes) and the error is corrected by the error detection unit 108 (St104; Yes), the failure determination unit 109 compares the reference signals corrected by the error detection unit 108 with an expected value that is set in advance for the pixel row R (St107) to perform failure determination. In this case, since the error in the reference signals due to the failure of the row-specific value reference pixels 122 has been resolved by the correction, it is possible to prevent failure determination due to the failure of the row-specific value reference pixels 122.

[0046] Note that when the error detection unit 108 detects an error in the reference signals output from the row-specific value reference pixels 122 that constitute pixel row R (St103; Yes), the failure determination unit 109 may not perform failure determination based on the reference signals, regardless of whether the error correction by the error detection unit 108 has been successful. In this case as well, by the failure determination unit 109 not performing failure determination, it is possible to prevent failure detection due to a failure of the row-specific value reference pixels 122.

[0047] [Effects of the Imaging Device] As described above, the imaging device 100 detects an error in the reference signal output by the row eigenvalue reference pixels 122 using the error correction code output by the correction code reference pixels 123. Furthermore, if there is no error in the reference signal or if the error in the reference signal has been corrected, the reference signal is used to determine whether or not there is a fault in the pixel row. This prevents an erroneous determination of a fault in the pixel row due to an error in the reference signal caused by a fault in the row eigenvalue reference pixels 122, and enables accurate fault determination of the pixel row.

[0048] One method for suppressing the effects of reference pixel failure is to multiplex reference pixels. Fig. 4 is a schematic diagram of a pixel array using this method. The pixel array 501 shown in the figure includes imaging pixels 521, reference pixels 522a, and reference pixels 522b. Each pixel row R of the pixel array 501 is made up of imaging pixels 521, reference pixels 522a, and reference pixels 522b. The reference pixels 522a are pixels that output a reference signal specific to the pixel row R. The reference pixels 522b are pixels that output the same reference signal as the reference pixels 522a, and the same number of reference pixels as the reference pixels 522a are required.

[0049] In this configuration, even if one of the reference pixels 522a and 522b fails and an error occurs in the reference signal, the other will output a correct reference signal. This makes it possible to suppress the effects of a reference pixel failure. However, it is necessary to provide the same number of reference pixels 522b as the reference pixels 522a, which increases the pixel mounting area. Although Figure 4 shows three reference pixels 522a and three reference pixels 522b, in reality, more reference pixels are required.

[0050] Another method for suppressing the influence of a reference pixel failure is to store information about the presence or absence of a reference pixel failure in an information storage mechanism built into the imaging device in advance, or to obtain the information from outside the imaging device. However, in this case, an information storage mechanism needs to be provided inside or outside the imaging device. In contrast, the imaging device 100 according to the present technology does not require such an information storage mechanism.

[0051] As described above, the imaging device 100 has excellent pixel area efficiency, can suppress the effects of reference pixel failures without requiring an information retention mechanism, and can accurately detect pixel row failures. Therefore, the imaging device 100 is suitable for applications where imaging is performed continuously, such as in-vehicle sensors, factory use, traffic monitoring, and biometric authentication. The imaging device 100 can also be used in any application where a CMOS image sensor can be used.

[0052] Second Embodiment A second embodiment of the present technology will be described.

[0053] [Configuration and Operation of Imaging Device] Fig. 5 is a block diagram of an imaging device 200 according to the second embodiment. Fig. 6 is a flowchart showing the operation of the imaging device 200. As shown in Fig. 5, the imaging device 200 includes a pixel array 201, an A / D converter array 202, a row scanning unit 203, a control unit 204, a signal processing unit 205, a voltage supply unit 206, a ramp signal supply unit 207, an error detection unit 208, and a failure determination unit 209.

[0054] The pixel array 201 is an array in which pixels made of CMOS (Complementary Metal Oxide Semiconductor) are arranged. Specifically, the pixel array 201 includes imaging pixels 221, row eigenvalue reference pixels 222, and correction code reference pixels 223. In Fig. 5 , the row eigenvalue reference pixels 222 are indicated by hatching with diagonal lines, and the correction code reference pixels 223 are indicated by hatching with dots.

[0055] The pixel array 201 is composed of rows and columns of pixels. FIG. 5 shows pixel rows R and pixel columns L each composed of pixels. As shown in the figure, the pixel array 201 is composed of a plurality of pixel rows R and a plurality of pixel columns L. Each pixel row R is composed of one or more imaging pixels 221, row-specific value reference pixels 222, and correction code reference pixels 223. The pixels constituting each pixel row R are connected to each other by row wiring 231, and the pixels constituting each pixel column L are connected to each other by column wiring 232.

[0056] The pixel row R includes a first pixel row R1 and a second pixel row R2. The row wiring 231 of the first pixel row R1 and the row wiring 231 of the second pixel row R2 are connected, and the first pixel row R1 and the second pixel row R2 are read out simultaneously. Although not shown in FIG. 5 , the other pixel rows R also include a first pixel row R1 and a second pixel row R2 that are read out simultaneously. The number of pixel rows R and pixel columns L that make up the pixel array 201 is not particularly limited.

[0057] The imaging pixels 221 photoelectrically convert incident light and accumulate electric charges. When a row selection signal is input from the row wiring 231, the imaging pixels 221 output a pixel signal corresponding to the amount of accumulated electric charge to the column wiring 232. The number of imaging pixels 221 constituting each pixel row R and each pixel column L is not particularly limited.

[0058] The row-specific value reference pixel 222 outputs a row-specific reference signal. ０ or V １ is supplied, and when a row selection signal is input from the row wiring 231, a fixed voltage V ０ and V １ The reference signal is output in accordance with either of the above.

[0059] Here, the reference signals output by the row-specific value reference pixels 222 are the same between the first pixel row R1 and the second pixel row R2. Hereinafter, the reference signals output by the row-specific value reference pixels 222 constituting the first pixel row R1 will be referred to as the "first reference signal," and the reference signals output by the row-specific value reference pixels 222 constituting the second pixel row R2 will be referred to as the "second reference signal." If there are no failures in the row-specific value reference pixels 222 in the first pixel row R1 and the second pixel row R2, the first reference signal and the second reference signal will be the same. Note that while only one row-specific value reference pixel 222 is shown in each pixel row R in FIG. 5 , in reality, a number of row-specific value reference pixels 222 capable of generating a unique reference signal are arranged in each pixel row R (see FIG. 3 ).

[0060] The correction code reference pixels 123 output an error correction code of the reference signal output by the row eigenvalue reference pixels 122. The method of the error correction code is not particularly limited, and may be a parity code, a checksum, a cyclic redundancy check (CRC), a Hamming code, or the like.

[0061] Hereinafter, the error correction code output by the correction code reference pixels 223 constituting the first pixel row R1 will be referred to as the "first error correction code," and the error correction code output by the correction code reference pixels 223 constituting the second pixel row R2 will be referred to as the "second error correction code." The first error correction code and the second error correction code are identical. Although only one correction code reference pixel 123 is shown in each pixel row R in FIG. 5 , in reality, a number of correction code reference pixels 123 sufficient to generate an error correction code for the reference signal of each pixel row R are arranged.

[0062] The A / D converter array 202 is an array in which A / D converters 241 are arranged. The A / D converters 241 are connected to the column wirings 232, and convert analog signals input from the column wirings 232, specifically, pixel signals, first reference signals, second reference signals, first error correction codes, and second error correction codes, into digital signals.

[0063] The row scanning unit 203 selects a pixel row R from which signals are to be read. When the row scanning unit 203 applies a voltage to the row wiring 231 of the pixel row R to be read, signals are output from the imaging pixels 221, row-specific value reference pixels 222, and correction code reference pixels 223 connected to this row wiring 231 to the column wiring 232 connected to each of them, and then read out. As described above, in the pixel array 201, the row wiring 231 is connected between the adjacent first pixel row R and second pixel row R2, so that the first pixel row R1 and second pixel row R2 are read out simultaneously. Hereinafter, this pair of the first pixel row R1 and second pixel row R2 that are read out simultaneously will be referred to as a "pixel row pair." The row scanning unit 203 sequentially selects pixel row pairs to be read out.

[0064] The control unit 204 is connected to and controls the row scanning unit 203 and the A / D converter 241. The signal processing unit 205 is connected to the imaging pixels 221 and the A / D converter 241 via column wiring 232, and generates image data based on pixel signals output from the imaging pixels 221. The voltage supply unit 206 supplies reference potentials for generating reference signals and error correction codes to the row eigenvalue reference pixels 222 and the correction code reference pixels 223. The ramp signal supply unit 207 supplies a ramp signal for A / D conversion to the A / D converter 241.

[0065] The error detection unit 208 detects an error in the reference signal based on the reference signal output from the row-specific value reference pixels 122 that constitute a specific pixel row R and the error correction code output from the correction code reference pixels 123 that constitute that pixel row R. Specifically, the error detection unit 208 reads out a first reference signal output from the row-specific value reference pixels 122 that constitute the first pixel row R1 of the pixel row pair selected by the row scanning unit 203, and a second reference signal output from the row-specific value reference pixels 122 that constitute the second pixel row R2 of the same pixel row pair (St201, see FIG. 6 ).

[0066] Furthermore, the error detection unit 208 performs an error detection process using the first error correction code output from the correction code reference pixels 223 that make up the first pixel row R1, and detects an error in the first reference signal (St202).

[0067] When the error detection unit 208 does not detect an error in the first reference signal (St203; No), it supplies this first reference signal as a reference signal for the first pixel row R1 and the second pixel row R2 to the failure determination unit 209. On the other hand, when the error detection unit 208 detects an error in the first reference signal (St203; Yes), it performs error detection processing using the second error correction code output from the correction code reference pixel 223 that constitutes the second pixel row R2, and detects an error in the second reference signal (St204).

[0068] When the error detection unit 208 does not detect an error in the second reference signal (St205; No), it supplies the second reference signal as a reference signal for the first pixel row R1 and the second pixel row R2 to the failure determination unit 209. On the other hand, when the error detection unit 208 detects an error in the second reference signal (St205; Yes), it notifies the outside, for example, the device in which the imaging device 200 is installed, that there is an abnormality in the captured image generated based on the output of the imaging pixels 221 (St206), and ends imaging.

[0069] The fault determination unit 209 determines whether or not there is a fault in the pixel row R based on the reference signal and the determination result by the error detection unit 208. Specifically, if the error detection unit 208 does not detect an error in at least one of the first reference signal and the second reference signal, the fault determination unit 209 compares the reference signal (first reference signal or second reference signal) supplied from the error detection unit 208 with the expected values ​​set for the first pixel row R1 and the second pixel row R2 (St 207). Note that the same expected value is set for the first pixel row R1 and the second pixel row R2 in each pixel row pair.

[0070] If the two match (St208; Yes), the failure determination unit 209 determines that no failure has occurred in the first pixel row R1 or the second pixel row R2. On the other hand, if the two do not match (St208; No), the failure determination unit 209 determines that a failure has occurred in the first pixel row R1 or the second pixel row R2.

[0071] If the reference signal does not match the expected value set for that pixel row R (first pixel row R1 and second pixel row R2) (No in St208), it is estimated that there is an abnormality in row scanning by the row scanning unit 203, a failure in the imaging pixels 221 that make up that pixel row R, or a failure in the row wiring 231 that makes up that pixel row R. Therefore, the failure determination unit 209 notifies the outside that there is an abnormality in the captured image generated based on the output of the imaging pixels 221 (St206), and terminates imaging. If the reference signal matches the expected value set for that pixel row R (Yes in St208), there is no abnormality in that pixel row R, so imaging continues.

[0072] On the other hand, if the error detection unit 208 detects errors in both the first reference signal and the second reference signal (St205; Yes), the failure determination unit 209 does not determine whether or not there is a failure due to the reference signals. If there are errors in the first reference signal and the second reference signal, it is estimated that a failure has occurred in the row-specific value reference pixels 222 in both the first pixel row R1 and the second pixel row R2. Therefore, if failure determination is performed, it will be determined that a failure has occurred in the pixel row R, even if no failure has occurred in pixels other than the row-specific value reference pixels 222 in the pixel row R. By not performing failure determination, the failure determination unit 209 can prevent detection of a failure due to a failure in the row-specific value reference pixels 222.

[0073] [Effects of the Imaging Device] As described above, the imaging device 200 detects an error in the reference signal output by the row-specific value reference pixel 222 using the error-correcting code output by the correction code reference pixel 223. Furthermore, if there is no error in the reference signal, or if a reference signal for a pixel row that is simultaneously read out is available, the reference signal is used to determine whether or not there is a fault in the pixel row. This prevents an erroneous determination of a fault in the pixel row due to an error in the reference signal caused by a fault in the row-specific value reference pixel 222, and enables accurate fault determination of the pixel row.

[0074] As described above, the imaging device 200 also has excellent pixel area efficiency, is capable of suppressing the effects of reference pixel failures without requiring an information retention mechanism, and is capable of accurately detecting pixel row failures. Therefore, the imaging device 200 is suitable for applications where imaging is performed continuously, such as in-vehicle sensors, factory use, traffic monitoring, and biometric authentication. The imaging device 200 can also be used in any application where a CMOS image sensor can be used.

[0075] (Hardware Configuration) The functional configuration in the first embodiment, particularly the error detection unit 108 and the fault determination unit 109, can be realized by an information processing device. The functional configuration in the second embodiment, particularly the error detection unit 208 and the fault determination unit 209, can also be realized by an information processing device. The hardware configuration of an information processing device 300 that can realize these functional configurations will be described below. Figure 7 is a schematic diagram showing this hardware configuration.

[0076] As shown in the figure, the information processing device 300 incorporates a CPU (Central Processing Unit) 1001 and a GPU (Graphics Processing Unit) 1002. An input / output interface 1006 is connected to the CPU 1001 and the GPU 1002 via a bus 1005. A ROM (Read Only Memory) 1003 and a RAM (Random Access Memory) 1004 are connected to the bus 1005.

[0077] The input / output interface 1006 is connected to an input unit 1007 including input devices such as a keyboard and a mouse through which a user inputs operation commands, an output unit 1008 that outputs a processing operation screen and images of processing results to a display device, a storage unit 1009 including a hard disk drive or the like that stores programs and various data, and a communication unit 1010 including a LAN (Local Area Network) adapter or the like that executes communication processing via a network typified by the Internet. Also connected is a drive 1011 that reads and writes data from a removable storage medium 1012 such as a magnetic disk, optical disk, magneto-optical disk, or semiconductor memory.

[0078] The CPU 1001 executes various processes in accordance with a program stored in a ROM 1003 or a program read from a removable storage medium 1012 such as a magnetic disk, optical disk, magneto-optical disk, or semiconductor memory, installed in a storage unit 1009, and loaded from the storage unit 1009 into a RAM 1004. The RAM 1004 also stores data necessary for the CPU 1001 to execute various processes as appropriate. The GPU 1002 executes calculations necessary for image rendering under the control of the CPU 1001.

[0079] In the information processing device 300 configured as described above, the CPU 1001 performs the above-described series of processes by, for example, loading a program stored in the memory unit 1009 into the RAM 1004 via the input / output interface 1006 and the bus 1005 and executing it.

[0080] The program executed by information processing device 300 can be provided by being recorded on removable storage medium 1012 such as a package medium, for example. The program can also be provided via a wired or wireless transmission medium such as a local area network, the Internet, or digital satellite broadcasting.

[0081] Furthermore, in the information processing device 300, the program can be installed in the storage unit 1009 via the input / output interface 1006 by attaching the removable storage medium 1012 to the drive 1011. The program can also be received by the communication unit 1010 via a wired or wireless transmission medium and installed in the storage unit 1009. Alternatively, the program can be installed in advance in the ROM 1003 or the storage unit 1009.

[0082] The program executed by the information processing device 300 may be a program that is processed chronologically in the order described in this disclosure, or may be a program that is processed in parallel or at the required timing, such as when called.

[0083] Furthermore, the entire hardware configuration of the information processing device 300 does not have to be installed in one device, and the information processing device 300 may be configured by multiple devices. Furthermore, part of the hardware configuration of the information processing device 300 may be installed in multiple devices connected via a network.

[0084] (About the present disclosure) The effects described in this disclosure are merely examples and are not limiting, and other effects may also be present. The description of multiple effects does not necessarily mean that these effects are exhibited simultaneously. It means that at least one of the effects described above can be obtained depending on the conditions, etc., and effects not described in this disclosure may also be exhibited. Furthermore, it is possible to combine at least two of the characteristic features described in this disclosure.

[0085] The present technology can also be configured as follows.

[0086] (1) An imaging device comprising: a pixel array in which pixels made of CMOS (Complementary Metal Oxide Semiconductor) are arranged, each pixel row being configured by imaging pixels outputting a pixel signal corresponding to incident light, row-specific value reference pixels outputting a row-specific reference signal, and correction code reference pixels outputting an error correction code of the reference signal, connected by wiring; an error detection unit that detects an error in the reference signal based on the reference signal output from the row-specific value reference pixels that constitute a specific pixel row among the plurality of pixel rows and the error correction code output from the correction code reference pixels that constitute the pixel row; and a fault determination unit that determines whether or not there is a fault in the pixel row based on the reference signal and the detection result by the error detection unit. (2) The imaging device according to (1), wherein, when the error detection unit does not detect an error in a reference signal output from a row-eigenvalue reference pixel constituting the pixel row, the error detection unit supplies the reference signal to the fault detection and determination unit as a reference signal for the pixel row, and when an error is detected in the reference signal output from the row-eigenvalue reference pixel constituting the pixel row, the error detection unit supplies a reference signal obtained by correcting the reference signal to the fault determination unit as a reference signal for the pixel row. (3) The imaging device according to (2), wherein the fault determination unit compares the reference signal supplied from the error detection unit with an expected value set for the pixel row, and determines that a fault exists in the pixel row if the reference signal does not match the expected value. (4) The imaging device according to (3), wherein, when the fault determination unit determines that a fault exists in the pixel row, the fault determination unit notifies that an abnormality exists in an image generated based on outputs of the imaging pixels. (5) The imaging device according to any one of (1) to (4) above, wherein, when the error detection unit detects an error in the reference signal output from the row-specific value reference pixel that constitutes the pixel row, the failure determination unit does not determine whether or not there is a failure in the pixel row.(6) The imaging device according to (5), wherein the error detection unit detects an error in a reference signal output from row-specific value reference pixels that constitute the pixel row, and if the reference signal cannot be corrected, notifies that an abnormality exists in the captured image generated based on the output of the imaging pixels. (7) The imaging device according to any one of (1) to (6), wherein the plurality of pixel rows are simultaneously read out and include a first pixel row and a second pixel row in which the reference signal and the error correction code are identical; the error detection unit detects an error in the first reference signal based on a first reference signal output from row-specific value reference pixels constituting the first pixel row and a first error correction code output from correction code reference pixels constituting the first pixel row, and when an error is detected from the first reference signal, detects an error in the second reference signal based on a second reference signal output from row-specific value reference pixels constituting the second pixel row and a second error correction code output from correction code reference pixels constituting the second pixel row; and the failure determination unit determines the presence or absence of a failure in the first pixel row and the second pixel row based on the first reference signal, the second reference signal, and a detection result by the error detection unit. (8) The imaging device according to (7), wherein, when the error detection unit does not detect an error in a first reference signal output from row-eigenvalue reference pixels constituting the first pixel row, it supplies the first reference signal to the failure determination unit as a reference signal for the first pixel row and the second pixel row, and when the error detection unit detects an error in the first reference signal output from the row-eigenvalue reference pixels constituting the first pixel row and does not detect an error in a second reference signal output from the row-eigenvalue reference pixels constituting the second pixel row, it supplies the second reference signal to the failure determination unit as a reference signal for the first pixel row and the second pixel row. (9) The imaging device according to (8), wherein the failure determination unit compares the reference signal supplied from the error detection unit with expected values ​​set for the first pixel row and the second pixel row, and determines that a failure exists in the first pixel row and the second pixel row when the reference signal does not match the expected value.(10) The imaging device according to (9), wherein, when determining that there is a failure in the first pixel row and the second pixel row, the failure determination unit notifies that there is an abnormality in a captured image generated based on output of the imaging pixels. (11) The imaging device according to any one of (7) to (10), wherein, when the error detection unit detects errors in both a first reference signal output from the row eigenvalue reference pixel that constitutes the first pixel row and a second reference signal output from the row eigenvalue reference pixel that constitutes the second pixel row, the failure determination unit does not determine the presence or absence of a failure in the first pixel row and the second pixel row. (12) The imaging device according to (11), wherein, when detecting errors in both the first reference signal output from the row eigenvalue reference pixel that constitutes the first pixel row and the second reference signal output from the row eigenvalue reference pixel that constitutes the second pixel row, the error correction unit notifies that there is an abnormality in a captured image generated based on output of the imaging pixels. (13) An imaging device control program that operates an information processing device as: an imaging pixel array in which pixels made of CMOS (Complementary Metal Oxide Semiconductor) are arranged, each pixel row being configured by connecting imaging pixels that output pixel signals corresponding to incident light, row-specific value reference pixels that output row-specific reference signals, and correction code reference pixels that output error correction codes for the reference signals by wiring; an error detection unit that detects an error in the reference signal based on a reference signal output from the row-specific value reference pixels that configure a specific pixel row and an error correction code output from the correction code reference pixels that configure the pixel row; and a fault determination unit that determines whether or not there is a fault in the pixel row based on the reference signal and the detection result by the error detection unit.(14) An imaging device control method, wherein an error detection unit forms a pixel array in which pixels made of CMOS (Complementary Metal Oxide Semiconductor) are arranged, and each pixel row is formed by connecting imaging pixels that output pixel signals corresponding to incident light, row-specific value reference pixels that output row-specific reference signals, and correction code reference pixels that output error correction codes for the reference signals by wiring, and detects an error in the reference signal based on a reference signal output from the row-specific value reference pixels that form a specific pixel row and an error correction code output from the correction code reference pixels that form the pixel row, and a fault determination unit determines whether or not there is a fault in the pixel row based on the reference signal and the detection result by the error detection unit.

[0087] REFERENCE SIGNS LIST 100, 200... Imaging device 101, 201... Pixel array 102, 202... A / D converter array 103, 203... Row scanning unit 104, 204... Control unit 105, 205... Signal processing unit 106, 206... Voltage supply unit 107, 207... Ramp signal supply unit 108, 208... Error detection unit 109, 209... Fault determination unit 121, 221... Imaging pixels 122, 222... Row eigenvalue reference pixels 123, 223... Correction code reference pixels 131, 231... Row wiring 132, 232... Column wiring

Claims

1. An imaging device comprising: a pixel array in which pixels made of CMOS (Complementary Metal Oxide Semiconductor) are arranged, each pixel row being configured by imaging pixels that output a pixel signal corresponding to incident light, row-specific value reference pixels that output a row-specific reference signal, and correction code reference pixels that output an error correction code for the reference signal, all connected by wiring; an error detection unit that detects an error in the reference signal based on the reference signal output from the row-specific value reference pixels that constitute a specific pixel row among the plurality of pixel rows and the error correction code output from the correction code reference pixels that constitute the pixel row; and a fault determination unit that determines whether or not there is a fault in the pixel row based on the reference signal and the detection result by the error detection unit.

2. An imaging device according to claim 1, wherein, when the error detection unit does not detect an error in a reference signal output from a row-specific value reference pixel constituting the pixel row, it supplies the reference signal to the fault detection and determination unit as a reference signal for the pixel row, and when an error is detected in the reference signal output from the row-specific value reference pixel constituting the pixel row, it corrects the reference signal and supplies the corrected reference signal to the fault determination unit as a reference signal for the pixel row.

3. An imaging device according to claim 2, wherein the failure determination section compares the reference signal supplied from the error detection section with an expected value set for the pixel row, and if the reference signal does not match the expected value, determines that there is a failure in the pixel row.

4. An imaging device according to claim 3, wherein, when the failure determination section determines that a failure exists in the pixel row, it notifies that there is an abnormality in the captured image generated based on the output of the imaging pixels.

5. An imaging device according to claim 1, wherein the failure determination section does not determine the presence or absence of a failure in a pixel row when the error detection section detects an error in the reference signal output from the row-specific value reference pixel that constitutes the pixel row.

6. An imaging device according to claim 5, wherein the error detection unit detects an error in a reference signal output from row-specific value reference pixels constituting the pixel row, and if the reference signal cannot be corrected, notifies that there is an abnormality in the captured image generated based on the output of the imaging pixels.

7. An imaging device according to claim 1, wherein the plurality of pixel rows are read out simultaneously and include a first pixel row and a second pixel row in which the reference signal and the error correction code are identical; the error detection unit detects an error in the first reference signal based on a first reference signal output from row-specific value reference pixels constituting the first pixel row and a first error correction code output from correction code reference pixels constituting the first pixel row, and when an error is detected from the first reference signal, detects an error in the second reference signal based on a second reference signal output from row-specific value reference pixels constituting the second pixel row and a second error correction code output from correction code reference pixels constituting the second pixel row; and the fault determination unit determines the presence or absence of a fault in the first pixel row and the second pixel row based on the first reference signal, the second reference signal and the detection result by the error detection unit.

8. An imaging device according to claim 7, wherein, when the error detection unit does not detect an error in a first reference signal output from row-eigenvalue reference pixels constituting the first pixel row, it supplies the first reference signal to the failure determination unit as a reference signal for the first pixel row and the second pixel row; when the error detection unit detects an error in the first reference signal output from the row-eigenvalue reference pixels constituting the first pixel row, and when the error detection unit does not detect an error in a second reference signal output from the row-eigenvalue reference pixels constituting the second pixel row, it supplies the second reference signal to the failure determination unit as a reference signal for the first pixel row and the second pixel row.

9. An imaging device according to claim 8, wherein the failure determination section compares the reference signal supplied from the error detection section with expected values ​​set for the first pixel row and the second pixel row, and if the reference signal and the expected value do not match, determines that there is a failure in the first pixel row and the second pixel row.

10. An imaging device according to claim 9, wherein, when the failure determination unit determines that there is a failure in the first pixel row and the second pixel row, it notifies that there is an abnormality in the captured image generated based on the output of the imaging pixels.

11. An imaging device according to claim 7, wherein the fault determination unit does not determine the presence or absence of a fault in the first pixel row and the second pixel row when the error detection unit detects an error in both a first reference signal output from the row-specific value reference pixels constituting the first pixel row and a second reference signal output from the row-specific value reference pixels constituting the second pixel row.

12. An imaging device according to claim 11, wherein, when the error correction unit detects an error in both a first reference signal output from row-specific value reference pixels constituting the first pixel row and a second reference signal output from row-specific value reference pixels constituting the second pixel row, it notifies that there is an abnormality in the captured image generated based on the output of the imaging pixels.

13. An imaging device control program that operates an information processing device as: an imaging pixel array in which pixels made of CMOS (Complementary Metal Oxide Semiconductor) are arranged, each pixel row being configured by connecting imaging pixels that output pixel signals corresponding to incident light, row-specific value reference pixels that output row-specific reference signals, and correction code reference pixels that output error correction codes for the reference signals by wiring; an error detection unit that detects errors in the reference signals based on reference signals output from the row-specific value reference pixels that configure a specific pixel row and error correction codes output from the correction code reference pixels that configure the pixel row; and a fault determination unit that determines whether or not there is a fault in the pixel row based on the reference signals and the detection results by the error detection unit.

14. A method for controlling an imaging device, in which an error detection unit forms a pixel array in which pixels made of CMOS (Complementary Metal Oxide Semiconductor) are arranged, and each pixel row is formed by wiring connecting imaging pixels that output pixel signals corresponding to incident light, row-specific value reference pixels that output row-specific reference signals, and correction code reference pixels that output error correction codes for the reference signals, and detects an error in the reference signal based on the reference signal output from the row-specific value reference pixels that form a specific pixel row and the error correction code output from the correction code reference pixels that form the pixel row, and a fault determination unit determines whether or not there is a fault in the pixel row based on the reference signal and the detection result by the error detection unit.

Images