JP2009177436A - Solid-state imaging apparatus, signal processor, and electronic information device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a solid-state imaging apparatus capable of detecting a blackening phenomenon and correcting a signal level of a pixel at a part where the blackening phenomenon is generated without adversely affecting an analog signal read from the pixel and its AD conversion processing. <P>SOLUTION: The solid-state imaging apparatus which outputs image data of an object by imaging of the object is provided with: an imaging part 101 which images the object to generate its analog image signal; an AD conversion part 102 which converts the analog image signal into a digital image signal; a blackening detection circuit 111 which detects a generation part of the blackening phenomenon in the image of the object on the basis of a level fluctuation pattern in which the signal level of the digital image signal fluctuates; and a blackening correction circuit 112 which corrects the signal level of the pixel in which blackening is generated, which is at the generation part of the blackening phenomenon on the basis of output of the blackening detection circuit. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a solid-state imaging device, a signal processing device, and an electronic information device. In particular, in a solid-state imaging device such as a CMOS image sensor, the occurrence of a blackening phenomenon is detected and the output level of a photoelectric conversion signal is corrected. And a signal processing device for detecting occurrence of the blackening phenomenon and correcting the output level, and an electronic information device such as a digital camera or a video camera using the solid-state imaging device and the signal processing device It is.

  Conventionally, a solid-state imaging device has a CCD image sensor that sequentially reads out electric charges obtained by photoelectric conversion in each pixel by a charge coupled device (CCD) and converts them into electric signals, and obtains photoelectric conversion in each pixel. There is a CMOS image sensor that reads out the converted electric charge after converting it into an electric signal.

  FIG. 11 is a diagram for explaining a conventional CMOS image sensor, and shows a configuration of a pixel in the CMOS image sensor.

  A pixel 30 constituting a conventional CMOS image sensor includes a photoelectric conversion unit (photodiode) 31 that generates a signal charge by photoelectric conversion, and a transfer transistor 32 that transfers the signal charge generated by the photodiode 31 to the floating diffusion layer 36. An amplifying transistor 34 that amplifies the potential of the floating diffusion layer 36; a reset transistor 33 that resets the charge of the floating diffusion layer 36; and a selection transistor 35 that reads the output signal of the amplifying transistor 34 to the read signal line L; have. Here, the transfer transistor 32 is controlled by a transfer signal TR, the reset transistor 33 is controlled by a reset signal RST, and the selection transistor 35 is controlled by a selection signal SEL.

  In the CMOS image sensor having the pixel 30 having such a configuration, a signal (read signal) read from the photoelectric conversion unit of each pixel to the read signal line L corresponds to a signal charge generated by photoelectric conversion. Since the signal component (photoelectric conversion signal) and the noise component are included, a constant corresponding to the reset voltage (reference voltage) of the floating diffusion layer 36 from the signal read from the photoelectric conversion unit by the differential amplifier. The reset signal is subtracted, and the difference signal is taken out as a photoelectric conversion signal in each pixel. Here, the reset signal is an output signal of the amplification transistor 35 corresponding to a reference voltage applied to the floating diffusion layer 36 by the reset transistor 33.

  However, in a solid-state imaging device such as a CMOS image sensor, when a high-brightness subject is picked up, an image blackening phenomenon (blackening phenomenon) occurs where an image of a high-brightness portion of the subject becomes black. That is, as shown in FIG. 12, when strong light is incident on the photoelectric conversion unit, the reset signal Vn becomes large due to light leakage in a state where the photoelectric conversion signal Vs is saturated at the maximum level (see point B) ( The output of the differential amplifier, that is, the difference signal (Vs−Vn) taken out as the signal component becomes zero. This is the generation mechanism of this blackening phenomenon.

  Therefore, in Patent Document 1, a level detection circuit for a signal (read signal) read from the photoelectric conversion unit and a reset signal is provided, and there is a signal or reset signal read from the photoelectric conversion unit by the level detection circuit. When it is determined that the level is equal to or higher than a certain level, an image without darkening is obtained by not performing differential processing. This Patent Document 1 includes a memory for storing a signal level obtained by AD converting the output of the differential amplifier, and a read signal or a reset signal from the photoelectric conversion unit is a certain level or higher. When it is determined that the signal level is read from the memory, the signal level is replaced with a predetermined level to obtain an image free from black sun.

  However, in the method disclosed in Patent Document 1, a detection circuit that detects the level of the analog signal read to the read signal line is provided in an analog signal path from the read signal line to the analog signal AD converter. Since it is necessary to add, even when the blackening phenomenon does not occur, the influence of the operation in the detection circuit may reach the analog signal.

  Patent Document 2 discloses a solid-state imaging device that takes measures against the blackening phenomenon by determining the occurrence of the blackening phenomenon in the AD conversion unit in consideration of the influence on the analog signal as described above. Has been.

  In the technique disclosed in this document 2, in the AD conversion unit that AD converts the analog signal read to the read signal line, the odd number AD conversion is based on the comparison error between the reset signal and the reference voltage. The AD conversion is performed on the reset signal and the comparison error is reflected, and the AD of the read signal is converted based on the comparison error between the signal (read signal) read from the photoelectric conversion unit and the reference voltage in the even AD conversion. Conversion is in progress.

  Here, the level of the reference voltage changes from a predetermined level at a constant rate as time elapses. Further, the AD conversion value of the analog signal is specifically obtained by measuring the time required for the level of the analog signal and the level of the reference voltage to be equal from the comparison start timing using a counter. This is equivalent to the count value. Further, by setting the AD conversion value of the reset signal as the down-count value of the counter and the AD conversion value of the read signal as the up-counter value of the counter, the read signal, the reset signal, That is, the photoelectric conversion signal at each pixel, which is the difference value, is obtained.

  In Patent Document 2, when it is determined that the reset signal is affected by light leakage in the AD conversion of the odd number of analog signals, that is, even if a certain period of time elapses, When the level of the reference voltage is not equal, the counter uses the latch output of these comparators, and the counter counts the maximum up-count value regardless of the result of AD conversion of the even-numbered analog signal performed thereafter. By making it output, the blackening phenomenon is suppressed.

  However, even in the technique disclosed in Patent Document 2, the signal level of the read signal line is greatly lowered after the reset of the floating diffusion layer until the AD conversion (odd number AD conversion) of the reset signal is performed. When more intense light is incident, the reset signal may not be detected even if the reset signal is affected by light leakage in odd-numbered AD conversion.

Therefore, in Patent Document 2, in consideration of such a case, when the potential level of the read signal line is lowered to a certain value or less when the AD conversion is performed on the read signal line an odd number of times. Discloses a circuit to which a correction circuit for raising the level of the read signal is connected.
JP 2004-248304 A JP 2007-243266 A

  As described above, in a conventional solid-state imaging device such as a CMOS image sensor, the level of an analog signal read from a pixel to a readout signal line is detected in order to avoid a darkening phenomenon in an image when a high-luminance subject is imaged. A level detection circuit is provided, and the level of the analog signal read to the read signal line is corrected based on the detection output of the level detection circuit, or the signal component generated by photoelectric conversion in the pixel is read from the pixel. The processing is changed.

  However, it is necessary to add a level detection circuit to the analog signal path for reading the signal component from the pixel in order to correct the analog signal level read to the readout signal line or to change the signal reading process from the pixel. Therefore, there is a problem that the analog signal itself can be adversely affected.

  The present invention has been made to solve the above-described conventional problems, and detects a blackening phenomenon without adversely affecting an analog signal read from a pixel and its AD conversion processing, and the blackening is detected. It is an object of the present invention to obtain a solid-state imaging device, a signal processing device, and an electronic information device using these that can correct the signal level of a pixel at a place where the phenomenon occurs.

  A solid-state imaging device according to the present invention is a solid-state imaging device that outputs image data of a subject by imaging the subject, an imaging unit that images the subject and generates an analog image signal thereof, and the analog image signal An AD converter for converting the digital image signal; a blackening detection circuit for detecting a blackening occurrence location in the image of the subject based on a level fluctuation pattern in which the signal level of the digital image signal changes; And a blackening correction circuit for correcting the signal level of the blackening occurrence pixel, which is a pixel located at the occurrence of the blackening phenomenon, based on the output of the blackening detection circuit. Achieved.

  According to the present invention, in the solid-state imaging device, the blackening detection circuit has a signal level of a first pixel of interest based on a signal level of the digital image signal sequentially input for each pixel constituting the imaging unit. When the pixel is smaller than the threshold level, a blackened pixel detection unit that determines that the pixel of interest is a blackened pixel, and a signal level that is sequentially input for each of the pixels, the pixel of interest is changed to a predetermined number of pixels. A high-brightness pixel detection unit that determines that the peripheral pixel is the first high-brightness pixel when the signal level of the peripheral pixel separated by a corresponding interval is higher than a second threshold level that is higher than the first threshold level And blackening determination when a second high-luminance pixel having a signal level greater than the third threshold level is detected based on the signal level sequentially input for each pixel. End signal A blackening phenomenon end determination unit to output, and when the target pixel is determined to be a blackened pixel and the peripheral pixel is determined to be a high luminance pixel, the target pixel of the first high luminance pixel When the pixel located adjacent to the pixel side is detected as the occurrence start position of the blackening phenomenon, and thereafter the blackening determination end signal is received, the first high luminance pixel and the second high luminance pixel It is preferable that a blackening phenomenon occurrence determination unit that determines that a blackening phenomenon occurs between the two is provided.

  In the solid-state imaging device according to the aspect of the invention, the blackening correction circuit may use a pixel located between the first high-brightness pixel and the second high-brightness pixel as the blackening generation pixel and set a signal level thereof. It is preferable to correct.

  In the solid-state imaging device according to the present invention, the high-intensity pixel detection unit delays the digital image signal sequentially input for each pixel, and a signal of the digital image signal output from the delay device It is preferable to include a high luminance determination circuit that determines that a peripheral pixel for the target pixel is a high luminance pixel when the level is higher than the second threshold level.

  According to the present invention, in the solid-state imaging device, the delay unit can change a delay amount of an input digital image signal to any one of a plurality of preset delay amounts. It is preferable that a pixel interval from the target pixel to the peripheral pixel is determined by adjusting the delay amount.

  In the solid-state imaging device according to the present invention, the imaging unit includes a control unit that controls the imaging unit to thin out and output an analog image signal obtained by imaging the subject in pixel units, and the control unit includes the delay unit It is preferable to control the delay amount to be a delay amount corresponding to the thinning-out rate of the analog image signal.

  In the solid-state imaging device according to the present invention, it is preferable that the second threshold level used in the high luminance pixel detection circuit and the third threshold level used in the blackening phenomenon end determination circuit are the same level.

  In the solid-state imaging device according to the present invention, it is preferable that the second threshold level used in the high luminance pixel detection circuit is different from the third threshold level used in the blackening phenomenon end determination circuit.

  According to the present invention, in the solid-state imaging device, the blackening correction circuit stores a signal level of a high luminance pixel located in the vicinity of a blackening occurrence pixel which is a pixel located at the blackening phenomenon occurrence location. It is preferable to replace the signal level of the blackening occurrence pixel located at the blackening phenomenon occurrence location with the stored signal level.

  In the solid-state imaging device according to the present invention, the solid-state imaging device includes a color filter array in which a predetermined number of color filters having different colors are repeatedly arranged in a predetermined arrangement pattern on each pixel, and the signal level storage unit includes the black level Among the pixels outside the blackening phenomenon occurrence spot, the blackening phenomenon occurrence spot has a color filter of the same color as the color filter on the plurality of blackening occurrence pixels located on the same pixel line within the blackening phenomenon occurrence spot. All the signal levels of the nearest pixels are held for each color of the color filter, and the blackening correction circuit stores the signal level of the blackening occurrence pixel located at the blackening phenomenon occurrence location. Of the levels, it is preferable to replace the signal level of the pixel having the same color of the black filter generation pixel and the color filter.

  According to the present invention, in the solid-state imaging device, the signal level storage unit stores even-numbered pixels and odd-numbered pixels when storing the signal level of a high-luminance pixel located in the vicinity of the blackening phenomenon occurrence location. The blackening correction circuit stores the signal level of the odd-numbered blackening occurrence pixel located at the blackening phenomenon occurrence position among the stored signal levels. The signal level of the even-numbered blackening occurrence pixel located at the blackening phenomenon occurrence location is replaced with the signal level of the odd-numbered high-luminance pixel of the even-numbered high-luminance pixel of the stored signal level. It is preferable to correct the signal level of the pixel located at the blackening phenomenon occurrence place in place of the pixel signal level.

  In the solid-state imaging device according to the aspect of the invention, it is preferable that the blackening correction circuit corrects the signal level of the blackening occurrence pixel located at the blackening occurrence place by replacing the signal level with a preset signal level.

  According to the present invention, in the solid-state imaging device, the blackening correction circuit may generate the blackening phenomenon only when a shutter period when the subject is imaged by the imaging unit is shorter than a preset setting value. It is preferable to correct the signal level of the blackening occurrence pixel located at.

  According to the present invention, in the solid-state imaging device, the blackening phenomenon occurrence determination unit is blackened only when the high-intensity pixel detection unit determines that a preset number of pixels are continuously high-intensity pixels. It is preferable to determine that the phenomenon has occurred.

  A signal processing apparatus according to the present invention is a signal processing apparatus that processes a digital image signal output from a solid-state imaging device that images a subject and outputs image data of the subject, and the signal level of the digital image signal is A blackening detection circuit for detecting a blackening phenomenon occurrence location in the image of the subject based on the changing level fluctuation pattern, and a blackening phenomenon occurrence location based on the output of the blackening detection circuit. It has a blackening correction circuit that corrects the signal level of a blackening occurrence pixel that is a pixel, and this achieves the above object.

  According to the present invention, in the signal processing device, the solid-state imaging device includes an imaging unit that images the subject and outputs an analog image signal thereof, and an AD conversion unit that converts the analog image signal into a digital image signal. It is preferable.

  According to the present invention, in the signal processing device, the blackening detection circuit has a signal level of a target pixel of a first level based on a signal level of the digital image signal sequentially input for each pixel constituting the imaging unit. When the pixel is smaller than the threshold level, a blackened pixel detection unit that determines that the pixel of interest is a blackened pixel, and a signal level that is sequentially input for each of the pixels, the pixel of interest is changed to a predetermined number of pixels. A high-brightness pixel detection unit that determines that the peripheral pixel is the first high-brightness pixel when the signal level of the peripheral pixel separated by a corresponding interval is higher than a second threshold level that is higher than the first threshold level And blackening determination when a second high-luminance pixel having a signal level greater than the third threshold level is detected based on the signal level sequentially input for each pixel. End signal A blackening phenomenon end determination unit to output, and when the target pixel is determined to be a blackened pixel and the peripheral pixel is determined to be a high luminance pixel, the target pixel of the first high luminance pixel When the pixel located adjacent to the pixel side is detected as the occurrence start position of the blackening phenomenon, and thereafter the blackening determination end signal is received, the first high luminance pixel and the second high luminance pixel It is preferable that a blackening phenomenon occurrence determination unit that determines that a blackening phenomenon occurs between the two is provided.

  In the signal processing apparatus according to the aspect of the invention, the blackening correction circuit may use a pixel located between the first high-brightness pixel and the second high-brightness pixel as the blackening generation pixel, and set the signal level thereof. It is preferable to correct.

  According to the present invention, in the signal processing apparatus, the blackening correction circuit stores a signal level of a high-luminance pixel located in the vicinity of a blackening occurrence pixel that is a pixel located at the blackening phenomenon occurrence location. It is preferable to replace the signal level of the blackening occurrence pixel located at the blackening phenomenon occurrence location with the stored signal level.

  According to the present invention, in the signal processing device, the solid-state imaging device includes a color filter array in which a predetermined number of color filters having different colors are repeatedly arranged in a predetermined arrangement pattern on each pixel. The signal level storage unit includes a color filter having the same color as a color filter on a plurality of blackening occurrence pixels located on the same pixel line within the blackening occurrence occurrence location, and a pixel outside the blackening occurrence occurrence location. Among them, the signal level of the pixel closest to the blackening occurrence location is held for each color of the color filter, and the blackening correction circuit is configured to detect the blackening occurrence pixel located at the blackening occurrence location. It is preferable to replace the signal level with the signal level of the pixel having the same color as that of the blackened pixel and the color filter among the stored signal levels.

  An electronic information device according to the present invention is an electronic information device having an image pickup unit that picks up an image of a subject, and the image pickup unit is the solid-state image pickup device, thereby achieving the object.

  An electronic information device according to the present invention is an electronic information device having an imaging unit that images a subject and a signal processing circuit that processes a digital image signal output from the imaging unit, and the signal processing circuit includes: The above signal processing apparatus achieves the above object.

  The operation of the present invention will be described below.

  In the present invention, in a solid-state imaging device that outputs image data of a subject by imaging the subject, an imaging unit that images the subject and generates an analog image signal thereof, and converts the analog image signal into a digital image signal Based on an AD conversion unit, a level fluctuation pattern in which the signal level of the digital image signal changes, a blackening detection circuit that detects a blackening phenomenon occurrence location in the image of the subject, and an output of the blackening detection circuit And a blackening correction circuit that corrects the signal level of the blackening occurrence pixel, which is a pixel located at the location where the blackening phenomenon occurs, so that the analog signal read from the pixel and its AD conversion process are used. It is possible to detect the blackening phenomenon and correct the signal level of the pixel where the blackening phenomenon occurs without adversely affecting the blackening phenomenon.

  Further, in the present invention, using a delay device that delays an input digital image signal, a target pixel that is a target for blackening determination and a peripheral pixel that is a target for high brightness determination in the vicinity of the target pixel. Since the interval can be changed, depending on the application of the solid-state imaging device, etc., by changing the interval between the target pixel and the neighboring pixels that are the targets of high luminance determination, erroneous determination of blackening phenomenon occurrence Can be suppressed.

  In the present invention, when thinning out the digital image signal read out from the imaging unit, the target pixel that is the target of blackening determination and the peripheral pixels that are the target of high brightness determination in the vicinity of the target pixel. Since the interval is changed in accordance with the thinning rate, detection of the blackening phenomenon occurrence place in the thinned image can be performed with the same accuracy as that of the image that has not been thinned.

  Further, in the present invention, the signal level of a high-luminance pixel located in the vicinity of the blackening occurrence pixel which is a pixel located at the blackening occurrence location is stored, and the blackening occurrence located at the blackening occurrence location is stored. Since the signal level of the pixel is replaced with the stored signal level, the signal level of the blackened pixel can be corrected without a sense of incongruity.

  Further, in the present invention, the signal level of a high-luminance pixel located in the vicinity of the blackening occurrence pixel which is a pixel located at the blackening occurrence location is stored, and the blackening occurrence located at the blackening occurrence location is stored. Since the signal level of the pixel is replaced with the signal level of a high-brightness pixel having a color filter of the same color as the blackening occurrence pixel, the correction of the signal level of the blackening occurrence pixel is not uncomfortable in a solid-state imaging device having a color filter. It can be carried out.

  Further, in the present invention, the threshold value when performing high-intensity determination of a pixel that determines the blackening phenomenon occurrence start position is different from the threshold value when performing high-intensity determination of the pixel that determines the blackening phenomenon occurrence end position. Therefore, the ease of determination can be changed between the determination of the blackening phenomenon occurrence start position and the determination of the blackening phenomenon occurrence end position.

  In the present invention, since it is determined whether or not to determine the blackening phenomenon occurrence location according to the shutter period in the imaging unit, it is possible to suppress erroneous determination of the blackening phenomenon occurrence location.

  In the present invention, since the high luminance pixel detection unit determines that the blackening phenomenon has occurred only when a predetermined number of pixels are continuously determined as high luminance pixels, It is possible to suppress erroneous determination of the occurrence of the crystallization phenomenon.

  As described above, according to the present invention, the digital video signal after AD conversion is treated as image data, the blackening phenomenon occurrence location is detected by pattern recognition, and the correction is performed by replacing the image data of the detected location. Therefore, the blackening phenomenon can be suppressed without affecting the analog signal and AD conversion.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
1 is a block diagram illustrating a solid-state imaging device according to Embodiment 1 of the present invention. FIG. 1A illustrates the overall configuration of the solid-state imaging device, and FIG. 1B illustrates the configuration of the solid-state imaging device. 2 shows a specific circuit configuration of the blackening detection circuit.

  The solid-state imaging device 100a according to the first embodiment includes a solid-state imaging device 100 that is made into one chip. The solid-state imaging device 100 photoelectrically converts an optical signal from a subject, and a photoelectric conversion signal obtained by the photoelectric conversion. A pixel unit (imaging unit) 101 that extracts As as an analog signal, an A / D conversion unit 102 that converts the analog signal As extracted by the pixel unit 101 into a digital signal Ds, and the A / D conversion unit 102 A digital signal processing unit 110 that performs digital signal processing on the digital signal Ds and outputs image data Id.

  This digital signal processing unit 110 detects black spots where blackening phenomenon has occurred in the captured image of the subject (blackening occurrence place) based on the digital signal Ds from the A / D conversion section 102. Based on the detection signal Fd of the blackening detection circuit 111 and the detection output Fd of the blackening detection circuit 111, the digital signal Ds is subjected to correction processing for correcting the signal level of the pixel located at the blackening phenomenon occurrence location in the captured image of the subject. And a digital signal processing circuit 113 that performs signal processing on the digital signal Cs that has been subjected to correction processing and outputs the pixel data Id from the solid-state imaging device 100.

  FIG. 2 is a graph showing a change in signal level at a location where a blackening phenomenon occurs in a captured image of the subject. In this figure, the position in the horizontal direction of the captured image is taken on the horizontal axis, and the level of the signal level is taken on the vertical axis, and the blackening phenomenon occurrence location on one line is shown.

  As shown in FIG. 2, at the portion where the blackening phenomenon occurs, the signal level is darkened over several pixels after the high signal level continues. Then, the state continues for a plurality of pixels, and returns to a high signal level again.

  Thus, when the blackening phenomenon occurrence place is seen in the horizontal direction, the change in the signal level has the above-mentioned characteristics. Therefore, the image data converted into the digital signal has a place having such a characteristic. By detecting it, it becomes possible to specify the blackening phenomenon occurrence location.

  Here, the case where the change in the horizontal direction of the signal level at the location where the blackening phenomenon occurs is shown, but since the same characteristic is seen in the vertical direction, the vertical direction or both the horizontal direction and the vertical direction are shown. By detecting a portion having the above-described characteristics, it is possible to specify a blackening phenomenon occurrence portion in a captured image displayed on one screen.

  FIG. 3 shows a change in the signal level in the blackening phenomenon occurrence portion shown in FIG. 2 in units of pixels. Using this figure, the blackening detection circuit 111 detects the blackening phenomenon occurrence location. A method will be described.

  First, the blackening detection circuit 111 has a high luminance determination threshold TH1 and a blackening determination threshold TH2, and performs high luminance determination and blackening determination on each pixel using the threshold. Then, the blackening detection circuit 111 confirms the determination result of the pixel Ps at a position separated by the determination pixel interval Dps on the left side from the pixel Pb determined to be blackened, and the pixel is determined to be a high luminance pixel. If it is determined that the blackening phenomenon has started from the pixel adjacent to the right of the determined high luminance pixel. Further, the blackening detection circuit 111 determines that the blackening phenomenon has ended at the pixel determined to be a high luminance pixel for the first time on the right side of the pixel at the blackening phenomenon occurrence start position. The blackening phenomenon occurrence location can be specified from the level fluctuation pattern in which the signal level of the image signal converted into the digital signal is changed by such a method.

  In the first embodiment, the pixel blackening determination is sequentially performed from the left side of one line. However, the pixel blackening determination may be sequentially performed from the right side of one line.

  In this embodiment, after detecting a pixel determined to be blackened (blackened determination pixel), the determination result of the pixel (peripheral pixel) Ps separated by the determination pixel interval is confirmed. The determined pixel Ps may be detected, and then the result of the blackening determination for pixels separated by the determination pixel interval may be confirmed.

  Further, although one threshold value TH1 is used for the high luminance determination, different high luminance determination threshold values may be set for the blackening phenomenon start point and the blackening phenomenon end point.

  The determination pixel interval Dps is preferably changeable because the interval between the high-luminance pixel and the blackened pixel may change due to thinning processing or the like in the pixel unit.

  Therefore, when the signal level of the pixel of interest is smaller than the threshold level TH2 based on the signal level of the digital signal Ds sequentially input for each pixel constituting the pixel unit 101, the blackening detection circuit 111 A blackened pixel detector 111a that determines that the pixel of interest is a blackened pixel, and a periphery that is separated from the pixel of interest by an interval corresponding to a predetermined number of pixels based on a signal level that is sequentially input for each pixel When the signal level of the pixel is greater than the threshold level TH1 that is greater than the threshold level TH2, a high-intensity pixel detection unit that determines that the peripheral pixel is the first high-intensity pixel Ps, and is sequentially input for each pixel When the second high-luminance pixel Pe having a signal level greater than the threshold level TH1 is detected based on the signal level to be output, the blackening phenomenon ends when the blackening determination end signal Ed is output When it is determined that the target pixel is a blackened pixel and the peripheral pixel is a high-brightness pixel, the constant circuit 111c and the target pixel Pd side of the first high-brightness pixel Ps are determined. When the adjacent pixel is detected as the occurrence start position of the blackening phenomenon and then the blackening determination end signal Ed is received, the first high luminance pixel Ps and the second high luminance pixel Pe Is provided with a blackening phenomenon occurrence determination unit 111d that determines that a blackening phenomenon has occurred.

  Here, the high luminance pixel detection unit includes a delay unit 111e that delays the digital signal sequentially input for each pixel, and the signal level of the digital signal Dds output from the delay unit 111e is the threshold level. When it is greater than TH1, the peripheral pixel Ps with respect to the target pixel Pd is determined to be a high luminance pixel, and a high luminance determination circuit 111b for outputting the determination output Ld is provided.

  FIG. 4 shows a method of correcting the image data at the blackening phenomenon occurrence place in the blackening correction circuit 112.

  When the blackening detection signal Fd is output from the blackening detection circuit 111, the blackening correction circuit 112 replaces the input data with the pixel data immediately before the correction start pixel, as shown in FIG. It corrects the image data of the phenomenon occurrence location.

  Thus, by using the pixel data immediately before the blackening phenomenon correction start pixel for correcting the blackening phenomenon occurrence location, the correction location can be corrected without a sense of incongruity.

  At that time, the pixel data (signal level) of even-numbered blackening determination pixels is the pixel data of even-numbered non-blackened pixels, and the pixel data (signal level) of odd-numbered blackened pixels is odd-numbered. By substituting the pixel data of the non-blackened pixels, it is possible to obtain a corrected image with no sense of incongruity. Such replacement of the pixel data takes into account the arrangement of the color filters, and is to be performed between pixels having the same color filter. Here, as the color filter, three color filters of green, red, and blue are used. In one pixel row, the green color filter and the red color filter are alternately arranged, and the pixel adjacent to the pixel row. In the rows, blue color filters and green color filters are alternately arranged, and these color filters are arranged so that the green color filters are not adjacent to each other between adjacent pixel rows. However, the arrangement of color filters and the types of colors are not limited to those described above.

  Next, the operation will be described.

  In the solid-state imaging device 100a according to the first embodiment, an analog image signal As obtained by imaging a subject is output from the pixel unit 101 to an A / D conversion unit 102. The A / D conversion unit 102 outputs the analog image signal As. The image signal As is converted into a digital image signal Ds.

  The digital image signal Ds is signal-processed by the digital signal processing unit 110 and output as subject image data Id.

  In the digital signal processing unit 110, the blackening detection circuit 111 detects a blackening occurrence location in the captured image based on a level fluctuation pattern in which the signal level of the digital image signal changes, and the blackening detection circuit Based on the detection output Fd 111, the blackening correction circuit 112 corrects the signal level of the pixel where the blackening occurs, and outputs the corrected digital image signal Cs to the digital signal processing circuit 113. Then, the digital signal processing circuit 113 performs signal processing such as image size reduction on the corrected digital image signal Cs, and outputs image data Id for display by this signal processing.

  The operation of the blackening detection circuit 111 at this time will be described below.

  First, in the blackened pixel detection circuit 111a, when the signal level of the target pixel Pb is lower than the threshold level TH2 based on the signal level of the digital image signal sequentially input for each pixel constituting the pixel unit 101, It is determined that the target pixel Pb is a blackened pixel.

  The digital image signal Ds to the blackened pixel detection circuit 111a is delayed by a delay unit 111e by a time corresponding to a predetermined number of pixel intervals, and the delayed digital image signal Ds is sent to the high luminance pixel detection circuit 111b. Entered. Then, the high-intensity pixel detection circuit 111b, based on the signal level sequentially input for each pixel, the peripheral pixels separated from the target pixel Pb by an interval corresponding to a predetermined number of pixels (a predetermined number of pixel intervals). When the signal level of Ps is greater than the threshold level TH1 that is greater than the threshold level TH2, it is determined that the peripheral pixel Ps is a high luminance pixel.

  Further, when the blackening phenomenon end determination circuit 111c detects a high-luminance pixel Pe having a signal level higher than the threshold level TH1, based on the signal level of the digital image signal sequentially input for each pixel, The determination end signal Ed is output.

  The blackening phenomenon occurrence determination circuit 111d determines that the target pixel Pb is a blackened pixel and determines that the peripheral pixel Ps is a high luminance pixel. When a pixel located adjacent to the target pixel Pb side is detected as the occurrence start position of the blackening phenomenon and then the blackening determination end signal Pe is received, the high luminance pixel Ps, the high luminance pixel Pe, It is determined that a blackening phenomenon has occurred at Rb during this period.

  As described above, in the first embodiment, a blackening detection circuit that detects a blackening phenomenon occurrence location in the digital signal processing unit of the solid-state imaging device, and a blackening correction circuit that corrects pixel data determined to be the blackening occurrence occurrence location. To correct the blackening phenomenon without affecting the analog signal. This is because if the blackening phenomenon that occurs in the solid-state imaging device is corrected by the function added to the analog circuit portion, the analog signal may be affected in places other than where the blackening phenomenon occurs. The blackening phenomenon can be corrected by a method that does not affect the analog signal.

  As described above, in the first embodiment, in a solid-state imaging device that outputs image data of a subject by imaging the subject, an imaging unit that images the subject and generates an analog image signal thereof, and the analog image signal is digitally converted. An A / D conversion unit for converting to an image signal, a blackening detection circuit for detecting a blackening occurrence location in an image of the subject based on a level fluctuation pattern in which the signal level of the digital image signal changes, and the blackening A blackening correction circuit that corrects a signal level of a blackening occurrence pixel, which is a pixel located at a place where the blackening phenomenon occurs, based on an output of the detection circuit, so that an analog signal read from the pixel and The blackening phenomenon can be detected and the signal level of the pixel where the blackening phenomenon occurs can be corrected without adversely affecting the AD conversion process.

  In addition, by using a delay device that delays the input digital image signal, it is possible to change the interval between the target pixel that is the target of blackening determination and the neighboring pixels that are the target of high brightness determination near the target pixel. Therefore, erroneous determination of occurrence of the blackening phenomenon can be suppressed by changing the interval between the target pixel and the peripheral pixels that are the targets of high luminance determination in accordance with the use of the solid-state imaging device.

  Further, the signal level of the high luminance pixel located near the blackening occurrence pixel which is the pixel located at the blackening occurrence location is stored, and the signal level of the blackening occurrence pixel located at the blackening occurrence location is stored. Since this is replaced with the stored signal level, the signal level of the blackened pixel can be corrected without a sense of incongruity.

  Further, the signal level of the high luminance pixel located near the blackening occurrence pixel which is the pixel located at the blackening occurrence location is stored, and the signal level of the blackening occurrence pixel located at the blackening occurrence location is stored. Since the signal level of the high luminance pixel having the color filter of the same color as the blackening occurrence pixel is replaced, the signal level of the blackening occurrence pixel can be corrected without a sense of incongruity in the solid-state imaging device having the color filter.

  Further, in the present embodiment, a threshold value for performing high-intensity determination of a pixel that determines a blackening phenomenon occurrence start position is different from a threshold value for performing high-intensity determination of a pixel that determines a blackening phenomenon occurrence end position. Thus, the ease of determination can be changed between the determination of the blackening phenomenon occurrence start position and the determination of the blackening phenomenon occurrence end position.

  In the first embodiment, the pixel data (signal level) on the left side of the blackening phenomenon occurrence point is used for correction of the blackening phenomenon occurrence point. (Signal level) may be used.

  Further, when correcting the signal level of the pixel (blackening occurrence pixel) located at the blackening occurrence location Rb, the signal level of the blackening occurrence pixel is set to the pixel data of the pixel adjacent to the blackening occurrence location Rb. However, when the signal level of the pixel (blackening occurrence pixel) located at the blackening phenomenon occurrence location Rb is corrected, the signal level of the blackening occurrence pixel may be replaced with constant pixel data.

Furthermore, in the first embodiment, the case where the blackening phenomenon occurrence location is detected based on the change in the horizontal direction of the signal level at the blackening occurrence occurrence location has been described. Since similar characteristics are also observed in the vertical direction, it is possible to determine the blackening phenomenon occurrence location based on the signal level in the vertical direction as in the first embodiment, and further, in the horizontal and vertical directions. It is also possible to determine where the blackening phenomenon has occurred based on the signal levels at both.
(Embodiment 2)
The solid-state imaging device according to the second embodiment of the present invention is obtained by adding a function of changing the delay amount of the high luminance pixel detection circuit input according to the thinning process to the first embodiment, which will be described in detail below.

  FIG. 5 is a block diagram illustrating the solid-state imaging device according to the second embodiment. FIG. 5A illustrates the overall configuration of the solid-state imaging device, and FIG. 5B illustrates the solid-state imaging device. A specific circuit configuration of the blackening detection circuit is shown.

  The solid-state imaging device 200 a according to the second embodiment includes a solid-state imaging device 200 that is made into one chip, and a control unit 203 that controls the solid-state imaging device 200. The solid-state imaging device 200 photoelectrically converts an optical signal from the subject, and extracts a photoelectric conversion signal As obtained by the photoelectric conversion as an analog signal. An A / D converter 102 that converts the analog signal As into a digital signal Ds, a digital signal processor 210 that performs digital signal processing on the digital signal Ds from the A / D converter 102 and outputs image data Id; have.

  Here, the pixel unit 201 is configured to perform a thinning process by a control signal Pc from the control unit 203.

  The digital signal processing circuit 210 according to the second embodiment includes a blackening detection circuit 211 that replaces the blackening detection circuit 111 in the digital signal processing circuit 110 according to the first embodiment. In addition to the function of the blackening detection circuit 111 of the first embodiment, blackening detection corresponding to the thinning-out processing in the pixel unit 201 is performed by the control signal Dc from the control unit 203.

  That is, the blackening detection circuit 211 includes a delayer 211e that can change the delay amount by the control signal Dc from the control unit 203, instead of the delayer 111e of the blackening detection circuit 111 of the first embodiment. is there.

  In the solid-state imaging device 200a of the second embodiment having such a configuration, when a subject is picked up by the pixel unit 201, when the thinning-out process of reading out the photoelectric conversion signal from the pixel is performed by the control signal Pc from the control unit 203, The delay amount of the delay device 211e is adjusted to a value corresponding to the thinning process by the control signal Dc from the control unit 203.

  As a result, even when the interval between the high-luminance pixel and the blackened pixel changes due to the thinning-out process, the blackening detection circuit 211 can satisfactorily determine whether the blackening phenomenon has occurred.

In each of the above embodiments, it is determined that a blackening phenomenon has occurred when it is determined that a pixel separated from the blackening determination pixel by the determination pixel interval is a high-luminance pixel. The condition for determining the occurrence of is not limited to this, and additional conditions may be added.
(Embodiment 3)
The solid-state imaging device according to the third embodiment of the present invention determines that the blackening phenomenon has occurred when the condition that the shutter period is shorter than the predetermined period is satisfied in addition to the determination condition of the first embodiment. It is a thing.

  That is, FIG. 6 is a block diagram for explaining the solid-state imaging device according to the third embodiment, FIG. 6 (a) shows the overall configuration of the solid-state imaging device, and FIG. 6 (b) shows the solid-state imaging device. A specific circuit configuration of the blackening detection circuit is shown.

  The solid-state imaging device 300a of the third embodiment includes a solid-state imaging device 300 that is made into one chip, and a control unit 303 that controls the solid-state imaging device 300.

  The solid-state imaging device 300 photoelectrically converts an optical signal from the subject and extracts a photoelectric conversion signal As obtained by the photoelectric conversion as an analog signal. An A / D converter 102 that converts the analog signal As into a digital signal Ds; a digital signal processor 310 that performs digital signal processing on the digital signal Ds from the A / D converter 102 and outputs image data Id; have.

  Here, the pixel unit 301 is configured such that the shutter period in the pixel unit 301 is adjusted by the control signal Sc from the control unit 303. Based on the image data Id output from the digital signal processing unit 310, the control unit 303 sets the pixel unit to shorten the shutter period as the luminance of the subject increases, that is, as the exposure amount per unit time increases. 301 is controlled.

  Further, the digital signal processing circuit 310 of the third embodiment includes a blackening detection circuit 311 that replaces the blackening detection circuit 111 in the digital signal processing circuit 110 of the first embodiment. In addition to the function of the blackening detection circuit 111 of the first embodiment, when the shutter period is shorter than the set value, that is, when the exposure amount is large, the blackening occurrence location is determined.

  That is, the blackening detection circuit 311 receives the control signal Sc from the control unit 303 together with the detection circuits 111a and 111b, the determination circuit 111c, and the delay unit in the blackening detection circuit 111 of the first embodiment, and the control signal Sc When the shutter period shown is smaller than the shutter period (set value) held in the register 311g, based on the shutter period determination circuit 311f that outputs the determination command signal Sh and the output signals from the circuits 111a to 111c and 311f. A blackening phenomenon occurrence determination circuit 311d for determining whether the blackening phenomenon has occurred.

  The blackening phenomenon occurrence determination circuit 311d performs the above process when the condition that the shutter period is smaller than a set value is satisfied in addition to the blackening phenomenon determination condition in the blackening phenomenon occurrence determination circuit 111d of the first embodiment. This is to determine blackening.

  Next, the function and effect will be described.

  In the third embodiment, the following effects are obtained in addition to the effects of the first embodiment.

  Here, the imaging state when the blackening phenomenon occurs will be considered. The blackening phenomenon occurs when the reset level increases to the vicinity of the signal level due to light leakage when a high-brightness subject is imaged by the solid-state imaging device. Therefore, when the blackening phenomenon occurs, a high-brightness subject is imaged, so that the shutter period is inevitably shorter than when the subject is not blackening. Therefore, by performing blackening phenomenon detection only when the shutter period is shorter than a certain value, erroneous determination of blackening phenomenon detection can be reduced.

  In other words, even in a normal image in which the blackening phenomenon does not occur, white spots or high luminance are detected at positions separated from the blackening determination pixels having a signal level smaller than the blackening determination threshold (TH2) in FIG. 3 by the determination pixel interval. If there is a subject with a high signal level such as a dark subject, it is determined that the blackening phenomenon has occurred even though the blackening phenomenon has not occurred, and the signal level is corrected. Can be avoided.

  Thus, in this embodiment, by adding a condition for determining that a blackening phenomenon has occurred in the blackening detection circuit, erroneous detection in the blackening detection circuit can be prevented.

In the above embodiment, the external terminal T3 is provided in the register 311g that holds the shutter period as a threshold value. For this reason, the threshold value of the shutter period for starting detection of the occurrence of blackening can be changed from the outside.
(Embodiment 4)
In the solid-state imaging device according to the fourth embodiment of the present invention, the blackening phenomenon occurs when the condition that the pixels determined to have high luminance are continuous in addition to the determination conditions of the first embodiment is satisfied. Is determined.

  FIG. 7 is a block diagram for explaining the solid-state imaging device according to the fourth embodiment. FIG. 7A shows the overall configuration of the solid-state imaging device, and FIG. 7B shows the solid-state imaging device. A specific circuit configuration of the blackening detection circuit is shown.

  The solid-state imaging device 400a of the fourth embodiment includes a solid-state imaging device 400 that is made into one chip, and the solid-state imaging device 400 includes the same pixel unit 101 and A / D conversion unit 102 as those of the first embodiment. Instead of the digital signal processing unit 110 in the solid-state imaging device 100 of the first embodiment, a digital signal processing circuit 410 having different determination conditions for occurrence of the blackening phenomenon is provided. Other configurations are the same as those of the first embodiment. Is the same.

  That is, the digital signal processing circuit 410 according to the fourth embodiment includes a blackening detection circuit 411 that replaces the blackening detection circuit 111 in the digital signal processing circuit 110 according to the first embodiment. In this blackening detection circuit 411, in place of the high luminance pixel detection circuit 111b of the first embodiment, the signal levels of a plurality of pixels separated from the target pixel by a certain pixel interval are larger than a certain level TH1. Is detected, a high luminance pixel detection circuit 411b for outputting a high luminance pixel detection signal is provided. The high luminance pixel detection circuit 411b performs high luminance determination when determining whether or not a pixel separated from the pixel determined to be smaller than the blackening determination threshold (TH2) is a high luminance pixel. It is determined together that a plurality of pixels are consecutive. In addition, the high luminance pixel detection circuit 411b is provided with terminals T4a and T4b for setting the upper limit and the lower limit of the number of continuous high luminance pixels from the outside. However, the high luminance pixel detection circuit 411b may not have a terminal for setting an upper limit and a lower limit of the number of continuous high luminance pixels.

  Next, the function and effect will be described.

  In the fourth embodiment, the following effects are obtained in addition to the effects of the first embodiment.

That is, when a high-luminance subject that causes a blackening phenomenon is imaged, a plurality of high-signal-level pixels Ps1 to Ps3 for which high-intensity determination is made are continuously provided around the blackening phenomenon occurrence portion as shown in FIG. Therefore, when the pixel Ps3 that is separated from the pixel Pb determined to be smaller than the blackening determination threshold (TH2) by the determination pixel interval Dps is determined to have high luminance, the pixels that have been determined to have high luminance are consecutive. In addition, it is possible to suppress erroneous detection due to white scratches or the like.
(Embodiment 5)
In the solid-state imaging device according to the fifth embodiment of the present invention, the blackening phenomenon occurs when the condition that the pixels determined to have high luminance are continuous in addition to the determination conditions of the third embodiment is satisfied. Is determined. That is, the features of Embodiment 3 and Embodiment 4 are combined.

  FIG. 9 is a block diagram for explaining the solid-state imaging device according to the fifth embodiment. FIG. 9A shows the overall configuration of the solid-state imaging device, and FIG. 9B shows the solid-state imaging device. A specific circuit configuration of the blackening detection circuit is shown.

  The solid-state imaging device 500a according to the fifth embodiment includes a solid-state imaging device 500 that is made into one chip, and a control unit 503 that controls the solid-state imaging device 500. The solid-state imaging device 500 photoelectrically converts an optical signal from the subject, and extracts a photoelectric conversion signal As obtained by the photoelectric conversion as an analog signal (imaging unit) 501 and the pixel unit 501. An A / D converter 102 that converts the analog signal As into a digital signal Ds; a digital signal processor 510 that performs digital signal processing on the digital signal Ds from the A / D converter 102 and outputs image data Id; have.

  Here, the pixel unit 501 and the control unit 503 are the same as the pixel unit 301 and the control unit 303 in the solid-state imaging device 300 of the third embodiment. That is, the pixel unit 501 is configured such that the shutter period in the pixel unit 501 is adjusted by the control signal Sc from the control unit 503. Based on the image data Id output from the digital signal processing unit 510, the control unit 503 is configured to reduce the shutter period as the subject brightness increases, that is, as the exposure amount per unit time increases. 501 is controlled.

  Further, the digital signal processing circuit 510 of the fifth embodiment includes a blackening detection circuit 511 that replaces the blackening detection circuit 411 in the digital signal processing circuit 410 of the fourth embodiment. In addition to the function of the blackening detection circuit 411 of the fourth embodiment, when the shutter period is shorter than the set value, that is, when the exposure amount is large, the blackening occurrence location is determined.

  That is, the blackening detection circuit 511 receives the control signal Sc from the control unit 503 together with the detection circuits 111a and 411b, the determination circuit 111c, and the delay device 111e in the blackening detection circuit 411 of the fourth embodiment, and performs the control. When the shutter period indicated by the signal Sc is smaller than the shutter period (set value) held in the register 311g, the shutter period determination circuit 311f that outputs the determination command signal Sh and the above-described circuits 111a, 411b, 111c, and 311f And a blackening phenomenon occurrence determination circuit 511d for determining the occurrence of the blackening phenomenon based on the output signal.

  The blackening phenomenon occurrence determination circuit 511d performs the above-described processing when the condition that the shutter period is smaller than a set value is satisfied in addition to the blackening phenomenon determination condition in the blackening phenomenon occurrence determination circuit 111d of the fourth embodiment. This is to determine blackening.

  In the fifth embodiment having such a configuration, in addition to the effect of the fourth embodiment, as in the third embodiment, the blackening phenomenon is detected only when the shutter period is shorter than a certain value. It is possible to reduce erroneous detection of phenomenon detection. As a result, by limiting the operating conditions of the blackening detection circuit and adding conditions for blackening phenomenon detection, false detection of blackening occurrence, and further, the signal level of the pixel at the blackening occurrence location Detection of a blackening phenomenon occurrence and correction of the signal level of the pixel can be realized without erroneous correction.

In each of the above embodiments, a solid-state imaging device is shown in which a digital signal processing unit is mounted in a single-chip solid-state imaging device. However, the solid-state imaging device of the present invention has a pixel unit and A / D conversion. The solid-state imaging device including the unit and the signal processing unit that performs signal processing of the output signal from the solid-state imaging device may be configured by separate chips.
(Embodiment 6)
FIG. 10 is a block diagram showing a solid-state imaging device according to Embodiment 6 of the present invention.

  The solid-state imaging device 600a according to the sixth embodiment includes a solid-state imaging device 600 that captures an image of a subject, and an image signal processing device 610a that processes an output signal from the solid-state imaging device. The image signal processing device 610a is configured by a separate chip.

  Here, like the solid-state image sensor 200 of Embodiment 2, the solid-state image sensor 600 photoelectrically converts an optical signal from the subject, and extracts a photoelectric conversion signal As obtained by the photoelectric conversion as an analog signal. (Imaging unit) and an A / D conversion unit that converts the analog signal As extracted by the pixel unit into a digital signal Ds. The image signal processing apparatus 610a includes the digital signal processing unit 210 and the control unit 203 in the second embodiment.

  Also in the solid-state imaging device 600a of the sixth embodiment having such a configuration, the same effects as those of the solid-state imaging device of the second embodiment can be obtained.

In the sixth embodiment, the configuration of the solid-state imaging device according to the second embodiment is taken as an example in which the solid-state imaging device constituting the solid-state imaging device and its signal processing unit are configured as separate chips. The solid-state imaging device in which the imaging element and its signal processing unit are configured as separate chips may be any solid-state imaging device of the first, third, and fifth embodiments.
(Embodiment 7)
Although not particularly described in the first to sixth embodiments, a digital camera such as a digital video camera or a digital still camera using at least one of the solid-state imaging devices of the first to sixth embodiments as an imaging unit, An electronic information device having an image input device such as an image input camera, a scanner, a facsimile, a camera-equipped mobile phone device, and the like will be described. The electronic information device according to the present invention performs high-quality image data obtained by using at least one of the solid-state imaging devices according to the first to sixth embodiments of the present invention as an imaging unit, and performs data recording after performing predetermined signal processing for recording. A memory unit such as a recording medium, a display unit such as a liquid crystal display device that displays the image data on a display screen such as a liquid crystal display screen after performing predetermined signal processing for display, and the image data for communication At least one of communication means such as a transmission / reception device that performs communication processing after the signal processing and image output means for printing (printing) and outputting (printing out) the image data.

  As mentioned above, although this invention has been illustrated using preferable embodiment of this invention, this invention should not be limited and limited to this embodiment. It is understood that the scope of the present invention should be construed only by the claims. It is understood that those skilled in the art can implement an equivalent range from the description of specific preferred embodiments of the present invention based on the description of the present invention and common general technical knowledge. It is understood that the patent documents cited in the present specification should be incorporated by reference into the present specification in the same manner as the content itself is specifically described in the present specification.

  According to the present invention, in the field of a solid-state imaging device, a signal processing device, and an electronic information device, a solid-state imaging device such as a CMOS image sensor detects a blackening phenomenon and corrects an output level of a photoelectric conversion signal. And a signal processing device for detecting occurrence of the blackening phenomenon and correcting the output level, and an electronic information device such as a digital camera or a video camera using the solid-state imaging device and the signal processing device And detecting the blackening phenomenon without adversely affecting the analog signal read from the pixel and its AD conversion process, and correcting the signal level of the pixel where the blackening phenomenon occurs It is something that can be done.

1 is a block diagram illustrating a solid-state imaging device according to Embodiment 1 of the present invention. FIG. 1A illustrates the overall configuration of the solid-state imaging device, and FIG. 1B illustrates the configuration of the solid-state imaging device. 2 shows a specific circuit configuration of the blackening detection circuit. FIG. 2 is a diagram for explaining the solid-state imaging device according to the first embodiment, and shows a change in signal level at a blackening phenomenon occurrence position in a captured image of a subject. FIG. 3 is a diagram showing a change in signal level in a pixel unit at a blackening phenomenon occurrence portion shown in FIG. FIG. 4 is a diagram for explaining the solid-state imaging device according to the first embodiment, and shows a method for correcting the image data of the blackening phenomenon occurrence place by the blackening correction circuit 112. FIG. 5 is a block diagram illustrating a solid-state imaging device according to Embodiment 2 of the present invention. FIG. 5A illustrates the overall configuration of the solid-state imaging device, and FIG. 5B illustrates the solid-state imaging device. A specific circuit configuration of the blackening detection circuit is shown. FIG. 6 is a block diagram illustrating a solid-state imaging device according to Embodiment 3 of the present invention. FIG. 6A illustrates the overall configuration of the solid-state imaging device, and FIG. 6B illustrates the solid-state imaging device. A specific circuit configuration of the blackening detection circuit is shown. FIG. 7 is a block diagram for explaining the solid-state imaging device according to the fourth embodiment. FIG. 7A shows the overall configuration of the solid-state imaging device, and FIG. 7B shows the solid-state imaging device. A specific circuit configuration of the blackening detection circuit is shown. FIG. 8 is a diagram for explaining the solid-state imaging device according to the fourth embodiment, and shows a change in signal level at a blackening phenomenon occurrence location in a captured image of a subject in units of pixels. FIG. 9 is a block diagram for explaining the solid-state imaging device according to the fifth embodiment. FIG. 9A shows the overall configuration of the solid-state imaging device, and FIG. 9B shows the solid-state imaging device. A specific circuit configuration of the blackening detection circuit is shown. FIG. 10 is a block diagram showing a solid-state imaging device according to Embodiment 6 of the present invention. FIG. 11 is a diagram for explaining a conventional CMOS image sensor, and shows a configuration of a pixel in the CMOS image sensor. FIG. 12 is a diagram for explaining the operation of the conventional CMOS image sensor.

Explanation of symbols

100a, 200a, 300a, 400a, 500a, 600a Solid-state imaging device 100, 200, 300, 400, 500, 600 Solid-state imaging device 101, 201, 301, 501 Pixel unit (imaging unit)
102 A / D converter 110, 210, 310, 410, 510 Digital signal processor 111, 211, 311, 411, 511 Blackening detection circuit 111a Blackening pixel detection circuit 111b, 411b High luminance pixel detection circuit 111c Blackening phenomenon End determination circuit 111d, 311d, 411d Blackening phenomenon occurrence determination circuit 111e, 211e Delayer 112 Blackening correction circuit 113 Digital signal processing circuit 203, 303, 503 Control unit 610a Image signal processing device

Claims (22)

A solid-state imaging device that outputs image data of a subject by imaging the subject,
An imaging unit that images the subject and generates an analog image signal thereof;
An AD converter for converting the analog image signal into a digital image signal;
A blackening detection circuit that detects a blackening occurrence location in the image of the subject based on a level fluctuation pattern in which the signal level of the digital image signal changes;
A solid-state imaging device comprising: a blackening correction circuit that corrects a signal level of a blackening occurrence pixel that is a pixel located at a place where the blackening phenomenon occurs based on an output of the blackening detection circuit. The solid-state imaging device according to claim 1,
The blackening detection circuit includes:
When the signal level of the target pixel is smaller than the first threshold level based on the signal level of the digital image signal sequentially input for each pixel constituting the imaging unit, the target pixel is a blackened pixel A blackened pixel detection unit for determining;
Based on the signal level sequentially input for each pixel, a second threshold level in which the signal level of surrounding pixels separated from the target pixel by an interval corresponding to a predetermined number of pixels is greater than the first threshold level A high-brightness pixel detection unit that determines that the surrounding pixel is the first high-brightness pixel when larger,
When a second high-luminance pixel having a signal level larger than the third threshold level greater than the first threshold level is detected based on the signal level sequentially input for each pixel, the blackening determination end signal A blackening phenomenon end determination unit that outputs
When it is determined that the target pixel is a blackened pixel and the peripheral pixel is determined to be a high brightness pixel, a pixel located adjacent to the target pixel side of the first high brightness pixel is determined. When the blackening phenomenon is detected as an occurrence start position and then the blackening determination end signal is received, the blackening phenomenon occurs between the first high luminance pixel and the second high luminance pixel. A solid-state imaging device including a blackening phenomenon occurrence determination unit that determines that the image has The solid-state imaging device according to claim 2,
The blackening correction circuit corrects the signal level of a pixel located between the first high-brightness pixel and the second high-brightness pixel as the blackening generation pixel. The solid-state imaging device according to claim 2,
The high-intensity pixel detection unit
A delay device for delaying the digital image signal sequentially input for each pixel;
A solid-state imaging device having a high-brightness determination circuit that determines that a peripheral pixel with respect to the target pixel is a high-brightness pixel when a signal level of a digital image signal output from the delay unit is higher than the second threshold level . The solid-state imaging device according to claim 4,
The delay unit is capable of changing a delay amount of an input digital image signal to any one of a plurality of preset delay amounts,
A solid-state imaging device in which a pixel interval from the target pixel to the peripheral pixel is determined by adjusting a delay amount of the delay device. The solid-state imaging device according to claim 5,
A controller that controls the imaging unit to output an analog image signal obtained by imaging the subject by thinning out the pixel unit;
The control unit controls the delay amount of the delay unit to be a delay amount corresponding to a thinning rate of the analog image signal. The solid-state imaging device according to claim 2,
The solid-state imaging device in which the second threshold level used in the high-luminance pixel detection circuit and the third threshold level used in the blackening phenomenon end determination circuit are the same level. The solid-state imaging device according to claim 2,
A solid-state imaging device in which a second threshold level used in the high-luminance pixel detection circuit and a third threshold level used in the blackening phenomenon end determination circuit are different levels. The solid-state imaging device according to claim 1,
The blackening correction circuit is
A signal level storage unit that stores a signal level of a high-luminance pixel located in the vicinity of the blackening occurrence pixel that is a pixel located at the blackening occurrence location;
A solid-state imaging device that replaces the signal level of a blackening occurrence pixel located at the blackening occurrence location with the stored signal level. The solid-state imaging device according to claim 9,
Provided with a color filter array in which a predetermined number of color filters of different colors are repeatedly arranged on each pixel so as to form a predetermined array pattern,
The signal level storage unit includes a color filter of the same color as a color filter on a plurality of blackening occurrence pixels located on the same pixel line within the blackening occurrence occurrence location, Among them, the signal level of the pixel closest to the blackening occurrence location is held for each color of the color filter,
The blackening correction circuit has the same signal level of the blackening occurrence pixel located at the blackening occurrence occurrence point as the color of the blackening occurrence pixel and the color filter among the stored signal levels. A solid-state imaging device that replaces the signal level of a pixel. The solid-state imaging device according to claim 9,
The signal level storage unit
When storing the signal level of the high-intensity pixel located in the vicinity of the blackening phenomenon occurrence location, the signal level is stored separately for even-numbered pixels and odd-numbered pixels,
The blackening correction circuit replaces the signal level of the odd-numbered blackening occurrence pixel located at the blackening occurrence location with the signal level of the odd-numbered high-luminance pixel of the stored signal level, In addition, the blackening phenomenon occurs by replacing the signal level of the even-numbered blackening occurrence pixel located at the blackening occurrence place with the signal level of the even-numbered high-intensity pixel among the stored signal levels. A solid-state imaging device that corrects the signal level of a pixel located at a location. The solid-state imaging device according to claim 1,
The blackening correction circuit is a solid-state imaging device that corrects a signal level of a blackening occurrence pixel located at a blackening occurrence place by replacing a signal level with a preset signal level. The solid-state imaging device according to claim 1,
The blackening correction circuit detects the signal level of the blackening occurrence pixel located at the blackening occurrence location only when a shutter period when the subject is imaged by the imaging unit is shorter than a preset setting value. Solid-state imaging device that corrects The solid-state imaging device according to claim 2,
The blackening phenomenon occurrence determination unit determines that the blackening phenomenon has occurred only when the high-brightness pixel detection unit determines that a predetermined number of pixels are continuously high-brightness pixels. A solid-state imaging device. A signal processing device that processes a digital image signal output from a solid-state imaging device that images a subject and outputs image data of the subject,
A blackening detection circuit that detects a blackening occurrence location in the image of the subject based on a level fluctuation pattern in which the signal level of the digital image signal changes;
A signal processing apparatus including a blackening correction circuit that corrects a signal level of a blackening occurrence pixel that is a pixel located at a place where the blackening phenomenon occurs based on an output of the blackening detection circuit. The signal processing device according to claim 15,
The solid-state imaging device is
An imaging unit that images the subject and outputs an analog image signal thereof;
A signal processing apparatus comprising: an AD conversion unit that converts the analog image signal into a digital image signal. The signal processing device according to claim 15,
The blackening detection circuit includes:
When the signal level of the target pixel is smaller than the first threshold level based on the signal level of the digital image signal sequentially input for each pixel constituting the imaging unit, the target pixel is a blackened pixel A blackened pixel detection unit for determining;
Based on the signal level sequentially input for each pixel, a second threshold level in which the signal level of surrounding pixels separated from the target pixel by an interval corresponding to a predetermined number of pixels is greater than the first threshold level A high-brightness pixel detection unit that determines that the surrounding pixel is the first high-brightness pixel when larger,
When a second high-luminance pixel having a signal level larger than the third threshold level greater than the first threshold level is detected based on the signal level sequentially input for each pixel, the blackening determination end signal A blackening phenomenon end determination unit that outputs
When it is determined that the target pixel is a blackened pixel and the peripheral pixel is determined to be a high brightness pixel, a pixel located adjacent to the target pixel side of the first high brightness pixel is determined. When the blackening phenomenon is detected as an occurrence start position and then the blackening determination end signal is received, the blackening phenomenon occurs between the first high luminance pixel and the second high luminance pixel. A signal processing apparatus including a blackening phenomenon occurrence determination unit that determines that the The signal processing device according to claim 17.
The blackening correction circuit corrects the signal level of a pixel located between the first high-brightness pixel and the second high-brightness pixel as the blackening generation pixel. The signal processing device according to claim 15,
The blackening correction circuit is
A signal level storage unit that stores a signal level of a high-luminance pixel located in the vicinity of the blackening occurrence pixel that is a pixel located at the blackening occurrence location;
A signal processing device that replaces the signal level of a blackening occurrence pixel located at the blackening occurrence location with the stored signal level. The signal processing device according to claim 19,
The solid-state imaging device includes a color filter array in which a predetermined number of color filters having different colors are repeatedly arranged on each pixel so as to form a predetermined arrangement pattern,
The signal level storage unit includes a color filter of the same color as a color filter on a plurality of blackening occurrence pixels located on the same pixel line within the blackening occurrence occurrence location, Among them, the signal level of the pixel closest to the blackening occurrence location is held for each color of the color filter,
The blackening correction circuit has the same signal level of the blackening occurrence pixel located at the blackening occurrence occurrence point as the color of the blackening occurrence pixel and the color filter among the stored signal levels. A signal processing device that replaces the signal level of a pixel. An electronic information device having an imaging unit for imaging a subject,
The electronic imaging device is the solid-state imaging device according to claim 1. An electronic information device having an imaging unit for imaging a subject and a signal processing circuit for processing a digital image signal output from the imaging unit,
The signal processing circuit is an electronic information device which is the signal processing device according to claim 15.

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