JP2013243785A - Imaging method and imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correct CCD dark current and high-intensity signal compression.SOLUTION: An imaging apparatus using a CCD comprises a 14-bit A/D and a 12-bit imaging signal processing circuit. After extending a high level of video signal output from effective pixels of a solid state imaging element, a smear calculated from VOB and dark current of the effective pixel are subtracted. A 14-bit video signal is compressed into 12 bits, and then signal processing is performed. Alternatively, the imaging apparatus using the CCD comprises a CDS, a 10-bit A/D, and an imaging signal processing circuit. The smear calculated from the VOB and reference voltage of the dark current CDS of the effective pixel are changed in units of pixels. Equivalently, after the CDS, the smear and the dark current of the effective pixel are subtracted from the video signal output from the effective pixels. With reference to the smear and the dark current of the effective pixels, the high level is extended to be subjected to signal processing in consideration of high-intensity compression of the smear and the dark current of the effective pixels.

Description

  The present invention relates to a method for improving a video signal of an imaging apparatus having a solid-state imaging device.

CCD (Charge-Coupled-Device) image sensors are more sensitive than solid-state image sensors, and there are few pixels called white scratches with abnormally high dark current levels, but white scratches at high temperatures, during high-sensitivity imaging, or during storage. There are many. In addition, when the CCD image pickup device picks up a high-brightness subject such as a spot light, excess charge leaks from the photodiode of the pixel picked up with the spot light into the vertical transfer path, and the same vertical as the pixel picked up the high-brightness subject. A video signal proportional to the illuminance of the spot light is superimposed on all the pixels in the direction, and a white vertical line called vertical smear is generated. If the CCD imaging device is provided with a storage surface outside the imaging surface to increase the vertical transfer speed, the vertical smear is reduced. However, if a storage surface is provided, the area of the CCD image sensor doubles and the price increases. Increasing the vertical transfer speed doubles power consumption and increases white scratches. Further, when the near-infrared sensitivity of the CCD image sensor is increased, the photodiode becomes deeper and white scratches increase. When the sensitivity is lowered by sweeping signal charge electrons of the photodiode of the CCD image pickup device to the overflow drain (using an electronic shutter), the vertical smear is lowered at a constant level, and the vertical smear is relatively To increase.
Therefore, conventionally, in order to reduce the influence of pixels called white scratches where the dark current level of the optical black pixel portion is abnormally high, the vertical optical black pixels (Vertical-Optical Black or below V-OB) of the CCD image sensor The vertical pixel signals output from the 12 lines of the portion are averaged and stored as a signal for one line, and the stored signal is subtracted from the output signal of the effective pixel portion of the solid-state imaging device. (See Patent Document 1)

Also, with the progress of integration of digital signal processing circuits, it is easy to store and arithmetically process output signals of multiple lines not only with video-only memory integrated DSPs but also with inexpensive general-purpose FPGAs (Field Programmable Gate Arrays). It became possible to realize. However, the circuit scale increases unless the signal processing gradation is reduced as much as possible. For gradations up to 12 bits, both an IC and a video signal processing IC for expanding the gradation range of an image by performing gradation correction separately for a high-luminance portion and a low-luminance portion on a pixel basis are commercially available. The gradation of the output video signal is generally 10 bits for transmission and 8 bits for industrial use.
Furthermore, CDS (Correlated) removes noise from the signal output from the CCD.
FEP (Front End Processor) with built-in double sampling, dark current correction, variable gain amplifier (automatic gain control, AGC) and ADC (Analog Digital Converter) that converts to digital video signal Vi is widely used. Gradation was conventionally 10 bits, but 12 bits and 14 bits have become commonplace, and 16 bits have been commercialized. An FEP in which the ADC is 22 bits and the AGC is placed after the ADC has also been commercialized.

Furthermore, an electron multiplying CCD image sensor (Electron
Multiplying-Charge Coupled Device (hereinafter abbreviated as EM-CCD) can be combined with an electronic cooling unit to increase sensitivity, enabling quasi-video monitoring without illumination for nighttime shooting of visible light and near infrared light. . Also, EM-CCD changes the sensitivity by 1.4 times at 0.1 V and changes by 1.8 times at 11 ° C during high electron multiplication where the voltage amplitude of CMG of the electrode for electron multiplication is high. To do. At low electron multiplication with low CMG voltage amplitude, the signal is multiplied after vertical transfer. Therefore, the shortage of transfer capacity of the photodiode and vertical transfer path is compensated, and when combined with electronic cooling that reduces dark current, The adjustment range is expanded. Furthermore, the gradation range of the video that is non-uniform in the screen due to variations in the storage capacity of the photodiode becomes uniform in the screen. However, when the CMG voltage amplitude is medium, the dark current is also electron-multiplied, the dark current becomes high level, the video signal component is saturated, and the gradation range of the video is lowered. When combined with electronic cooling that reduces dark current, the temperature is improved to about half at about 6 degrees. However, the dark current becomes high level, the video signal component is saturated, and the gradation range of the video is lowered. In addition, when the high CMG voltage amplitude is high, the horizontal modulation rate is reduced and the high luminance signal is compressed, so the EM-CCD is particularly strongly electronically cooled to minimize the dark current and the CMG voltage amplitude is also minimized. Even so, the dark current is at a high level, the video signal component is saturated, and the gradation range of the video is lowered (see Non-Patent Document 1 and Non-Patent Document 2). Moreover, it is difficult to dissipate heat in the electronic cooling of the EM-CCD.

Further, the EM-CCD generates a video signal having a lot of vertical smear components. In addition to the dark current, the vertical smear component reaches a high level, and the video signal including the dark current and the vertical smear component reaches a high level. Therefore, not only the CMG but also a signal circuit outside the EM-CCD easily saturates. Even when the EM-CCD is electronically cooled, not only the dark current but also the level of white scratches and vertical smear are high in addition to the dark current, and the video signal including the dark current and the vertical smear component is saturated. As a result, in addition to the dark current, the amount of error in excess or deficiency in vertical smear correction increases, white vertical stripes remain, black vertical stripes occur, and the gradation range of the image decreases. As a result, it is an obstacle to nighttime monitoring when high-intensity external illumination light directly enters the screen.
In addition, when the CCD output of the effective pixel becomes more saturated than the saturated saturation light, the vertical transfer path becomes oversaturated due to excessive charge generated by the photodiode and overflowing the vertical transfer path, and the image of the strong incident light The bottom of the screen is in a white state called blooming with a supersaturation level higher than the vertical smear. In addition, the supersaturated incident light that becomes the CCD output video signal that is oversaturated and reaches the limit level has a supersaturation level higher than that of the vertical smear in order from the bottom of the screen of the image of the strong supersaturated incident light as the incident light intensity increases. The horizontal transfer path also becomes supersaturated due to abnormally strong supersaturated incident light, and the vertical smear at the top of the screen sinks, and white streaky horizontal smears are revealed in the horizontal direction. descend. When the intensity of abnormally strong supersaturated incident light is further increased, white spreads over the entire screen. The incident light that is the source of smear and blooming is hereinafter referred to as the light source.

In addition, in a solid-state imaging device using a CCD imaging device, in order to reduce vertical smear so as not to be affected by dark current of the CCD imaging device such as white scratches or high level compression, four lines of vertical light-shielded video are displayed. The average signal of each vertical pixel signal is calculated, the horizontal signal is also averaged, the low level and the high level are compressed, and subtracted from the video signal output from the effective pixel on the light receiving surface of the CCD image sensor (see Patent Document 2). .
Furthermore, in a solid-state imaging device using a CCD image sensor, the vertical smear is reduced so as not to be affected by the dark current of the CCD image sensor such as white scratches, so that the effective pixel on the light receiving surface of the CCD image sensor is read out. After correcting dark current unevenness in the vertical direction of the screen of the signal obtained from the four lines of vertical shading pixels, the second value is calculated from the minimum value of each vertical pixel signal of the four lines of vertical shading video, and the vertical smear correction signal And the gain is varied in accordance with the video AGC, and subtracted from the post-AGC video signal output from the effective pixels on the light receiving surface of the solid-state imaging device. Also, the signal output from the solid-state image sensor is A / D converted to 14 bits, the representative value signal is calculated and attenuated to 15/16, and output from the effective pixels on the light receiving surface of the CCD image sensor. Subtraction is performed from the video signal (see Patent Document 3).

JP 07-067038 A JP2007-150770 JP2008-109639

TI TC246RGB-B0680 x 500 PIXELIMPACTRON TM PRIMARY COLOR CCD CCD SENSOR SOCS087-DECEMBER2004-REVISEDMARCH 2005 DesertStar Systems Night and Low-Light Imaging with FrogEye TM and SharkEyeTM DigitalCameras Application Note 2nd Edition October 28 2005

  An object of the present invention is to reduce the gradation range of a video signal, such as whiteout of a video signal output from a CCD image sensor, a false signal near a black level, subduction below a black level, or white at a supersaturated level. There is to expand.

  In order to solve the above-described problems, the present invention provides a solid-state imaging device, a first acquisition unit that acquires a video signal output from an effective pixel on the light-receiving surface of the solid-state imaging device, and an upper portion of the light-receiving surface of the solid-state imaging device or A signal obtained by extending a high level of a video signal output from an effective pixel acquired by the first acquisition unit in a solid-state imaging device having a second acquisition unit that acquires a signal output from a lower light-shielded pixel And an approximate dark current signal or smear signal calculated using the signal of the shaded pixel at the top or bottom, or a signal obtained by expanding a high level of the total signal of the approximate dark current signal and the smear signal, and the two expanded signals It is an imaging method characterized in that at least one of the signals with a differential signal is used for controlling an output video signal of the solid-state imaging device.

  Also, a solid-state image sensor, a first acquisition unit that acquires an image signal output from an effective pixel on the light-receiving surface of the solid-state image sensor, and a light-shielded pixel above or below the light-receiving surface of the solid-state image sensor. In a solid-state imaging device having a second acquisition unit for acquiring a signal, a signal obtained by extending a high level of a video signal output from an effective pixel acquired by the first acquisition unit, and a light-shielded pixel at the top or bottom The difference between the approximate dark current signal or smear signal calculated using the above signal or a signal obtained by extending the high level of the total signal of the approximate dark current signal and the smear signal is calculated, and the calculated signal is used as the solid-state imaging device. It is an imaging method characterized by being used for controlling the output video signal.

  Furthermore, it outputs from the solid-state image sensor, the 1st acquisition part which acquires the video signal output from the effective pixel of the light-receiving surface of the solid-state image sensor, and the light-shielded pixel above or below the light-receiving surface of the solid-state image sensor In a solid-state imaging device having a second acquisition unit for acquiring a signal, an approximate dark current signal or a smear signal calculated using a signal of a light-shielded pixel in the upper part or the lower part, or a sum signal of the approximate dark current signal and the smear signal Or subtracting the high level of the video signal output from the effective pixel acquired by the first acquisition unit from the extended signal, or approximating the dark current signal or smear signal or approximating dark Subtract the total signal of the current signal and the smear signal and then subtract the approximate dark current signal or smear signal or the total signal of the approximate dark current signal and smear signal. An image pickup method characterized in that one of the signals to extend the high level of the video signal output from the effective pixel acquired by the first acquisition unit subtracted to the signal is processed into an output video signal is there.

  In the above, the Nth value (N is a natural number) from the minimum value of each vertical pixel signal of the plurality of lines of the signal output from the shielded pixel acquired by the second acquisition unit, and M (M Is a natural number) Whether to calculate at least one representative value signal calculated from an average value less than the first value or a value less than the Mth value from other maximum values as an approximate dark current signal including a smear signal Or a first signal storing a signal output from the effective pixel acquired by the first acquisition unit at the time of light shielding and a signal output from the light-shielded pixel acquired by the second acquisition unit at the time of light shielding. Means (all pixel memory) and means for calculating an average value of light-shielded pixels at the upper and lower parts of a plurality of lines of signals output from the light-shielded pixels acquired by the second acquisition unit, The dark current reference value is stored in one means, and The average value of the upper and lower light-shielded pixels of a plurality of lines of signals output from the light-shielded pixels acquired by the second acquisition unit is calculated, and the ratio between the upper and lower light-shielded pixel reference values is stored in the memory The approximate dark current signal is calculated over the dark current reference value of one means, or the signal output from the effective pixel obtained by the first obtaining unit at the time of light shielding and the second obtaining unit at the time of light shielding. The first means (all pixel memory) for storing the acquired signal output from the shielded pixel is stored, the dark current reference value is stored in the first storage means, and acquired by the second acquisition unit. The minimum value of the signal output from the light-shielded pixel is calculated, and the approximate dark current signal is obtained by multiplying the ratio of the light-shielded pixel reference value of the storage first means with the dark current reference value of the storage first means. Calculate at least one of the calculated values and the calculated signal Is used for controlling an output video signal of the solid-state imaging device.

  Further, in the above, the solid-state imaging device, A / D of 12 bits or more, a video signal processing circuit of 10 bits or more, and an all pixel memory of 14 bits or more, and a dark current reference value is stored in the all pixel memory, The ratio of the current total amount of dark current of the VOB and the total amount of dark current of the reference VOB is an approximate value of dark current multiplication, and the high level of the video signal output from the effective pixel acquired by the first acquisition unit is After decompression, a value obtained by multiplying the difference between the representative value signal, the dark current of the reference effective pixel of the screen memory and the dark current of the reference VOB by the approximate value of dark current multiplication is subtracted from the representative value signal, and white An image pickup apparatus, wherein a compressed 10-bit video signal is signal-processed by the video signal processing circuit.

  In the above, the solid-state imaging device, the noise reduction circuit, a means for offsetting the reference voltage of the noise reduction circuit, an A / D of 10 bits or more, a video signal processing circuit of 10 bits or more, and a 13 + Nbit all-pixel memory. The dark current reference value is stored in all the pixel memories, and the ratio between the current representative value of the VOB dark current and the representative value of the dark current of the reference VOB is an approximation of the dark current multiplication, and the dark current of the VOB The reference voltage of the noise reduction circuit is offset by the current representative value (subtracting the current total amount of VOB dark current from the video signal), and high luminance compression corresponding to the current total amount of VOB dark current is also considered. The image pickup apparatus is characterized in that the high luminance of the video signal is expanded and signal-processed based on the offset of the reference voltage corresponding to the current total amount of dark current of the VOB.

  Further, the noise reduction circuit, means for variably offsetting the reference voltage of the noise reduction circuit in units of pixels, an A / D of 10 bits or more, a video signal processing circuit, and an all pixel memory of 14 bits or more are provided. The dark current reference value is stored, and the ratio of the current representative value of the VOB dark current and the representative value of the dark current of the reference VOB is an approximation of dark current multiplication, and the reference voltage of the noise reduction circuit is set to all pixels. Offset by the current approximate value of the dark current (subtract the current approximate value of the dark current of all pixels from the video signal) and also consider high-intensity compression of the current approximate value of the dark current of all pixels An image pickup apparatus is characterized in that a high luminance of a video signal is expanded and signal processing is performed based on a current approximate value of dark current of all pixels.

  Further, the optical system, the solid-state imaging device, a first acquisition unit that acquires a video signal output from an effective pixel on the light-receiving surface of the solid-state imaging device, and light-shielded pixels above or below the light-receiving surface of the solid-state imaging device In a solid-state imaging device having a second acquisition unit that acquires a signal to be output, N is determined from the minimum value of each vertical pixel signal of a plurality of lines of signals output from the light-shielded pixels acquired by the second acquisition unit. (N is a natural number) th value, at least a representative value signal calculated from an average value less than the Mth (M is a natural number) value from the maximum value, or a value less than the Mth value from other maximum values One is calculated, and when the representative value signal reaches a predetermined level or higher, the optical attenuation means (such as an optical diaphragm or a variable ND filter) provided in the optical system optically attenuates the incident light, and the solid-state image sensor Photodiode signal charge Swept the child into the overflow drain is an imaging method which is characterized in that at least one of the (electronic shutter performs) that.

  As described above, according to the present invention, the video signal output from the CCD image pickup device is whitened, false signals near the black level, sinking below the black level, or white of the supersaturated level is reduced. The gradation range is expanded.

The overall configuration of an embodiment of the present invention in the case where the high-intensity compression of the effective pixel signal is expanded to subtract the second value (the median value in 3 lines) from the minimum value when V-OB is 3 lines or more. Block diagram showing imaging device The overall configuration of an embodiment of the present invention in the case where the high-intensity compression of the signal of the effective pixel is expanded to subtract the third value (the median value in 5 lines) from the minimum value when V-OB is 5 lines or more. Block diagram showing imaging device An image pickup apparatus having an overall configuration according to an embodiment of the present invention in which high-intensity compression of a signal of an effective pixel is expanded and V-OB is subtracted using a digital AGC (Digital AGC) with a minimum value of 2 lines or more Block diagram showing The block diagram which shows the imaging device of the whole structure of one Example of this invention in the case of decompressing the high-intensity compression of the signal of an effective pixel and subtracting the average value excluding the maximum value when V-OB is 3 lines or more The block diagram which shows the imaging device of the whole structure of one Example of this invention when decompressing the high-intensity compression of the signal of an effective pixel, and subtracting the average value except the maximum value and the minimum value when V-OB is 4 lines or more A block showing an image pickup apparatus having an overall configuration according to an embodiment of the present invention in which high-intensity compression of a signal of an effective pixel is expanded and V-OB is an average value excluding the maximum value and the second largest value at 4 lines or more Figure One embodiment of the present invention in which high-intensity compression of the effective pixel signal is expanded to subtract the second value from the minimum value (median value in three lines) and the effective pixel dark current when V-OB is 3 lines or more. The block diagram which shows the imaging device of the whole structure of an Example The overall configuration of an embodiment of the present invention in the case where the high-intensity compression of the signal of the effective pixel is expanded to subtract the third value (the median value in 5 lines) from the minimum value when V-OB is 5 lines or more. Block diagram showing imaging device An image pickup apparatus having an overall configuration according to an embodiment of the present invention in which high-intensity compression of a signal of an effective pixel is expanded and V-OB is subtracted using a digital AGC (Digital AGC) with a minimum value of 2 lines or more Block diagram showing The block diagram which shows the imaging device of the whole structure of one Example of this invention in the case of decompressing the high-intensity compression of the signal of an effective pixel and subtracting the average value excluding the maximum value when V-OB is 3 lines or more The block diagram which shows the imaging device of the whole structure of one Example of this invention when decompressing the high-intensity compression of the signal of an effective pixel, and subtracting the average value except the maximum value and the minimum value when V-OB is 4 lines or more An image pickup apparatus having an overall configuration according to an embodiment of the present invention in which high-intensity compression of a signal of an effective pixel is expanded to subtract an average value excluding a maximum value and a second largest value when V-OB is 4 lines or more. Block diagram shown High-intensity compression of the effective pixel signal is expanded to calculate an approximate value of dark current multiplication using the minimum value when V-OB is 2 lines or more, and the V-OB minimum value is subtracted from the effective pixel dark current. The block diagram which shows the imaging device of the whole structure of one Example of this invention when doing When the effective pixel signal V-OB is 2 lines or more, the approximate value of the dark current multiplication is calculated using the minimum value, and the V-OB minimum value and the effective pixel dark current are subtracted to obtain the V-OB minimum value. The block diagram which shows the imaging device of the whole structure of one Example of this invention in the case of extending | stretching high-intensity compression according to the dark current of an effective pixel An approximate value of dark current multiplication is calculated using the second from the minimum value of V-OB of the effective pixel signal, the second and the dark current of the effective pixel are subtracted from the minimum value of V-OB, and the minimum of V-OB is obtained. The block diagram which shows the imaging device of the whole structure of one Example of this invention in the case of extending | stretching high-intensity compression according to the dark current of the 2nd and effective pixel from a value When the effective pixel signal V-OB is 2 lines or more, the approximate value of the dark current multiplication is calculated using the minimum value, and the V-OB minimum value and the effective pixel dark current are subtracted to obtain the V-OB minimum value. The block diagram which shows the imaging device of the whole structure of one Example of this invention in the case of extending | stretching high-intensity compression according to the dark current of an effective pixel The block diagram which shows the imaging device of the whole structure of one Example of this invention in the case of decompressing the high-intensity compression of a pixel signal and calculating a supersaturation signal using 2nd from the minimum value when V-OB is 3 lines or more The block diagram which shows the imaging device of the whole structure of one Example of this invention in the case of calculating a supersaturation signal using the average value except the maximum value and the 2nd largest value when V-OB of a pixel signal is 4 lines or more Flowchart of an embodiment of the present invention for detecting the second value from the minimum value of V-OB as a representative value Flowchart of an embodiment of the present invention for detecting the third value from the minimum value of V-OB as a representative value Flowchart of an embodiment of the present invention for detecting the minimum value of V-OB as a representative value The flowchart of one Example of this invention which detects the average value except the maximum value of V-OB as a representative value The flowchart of one Example of this invention which detects the average value except the maximum value and minimum value of V-OB as a representative value A flowchart for detecting an average value excluding the maximum value of V-OB and the second largest value as a representative value. Schematic table showing detection of dark current value including smear in V-OB in one embodiment of the present invention and in the prior art FIG. 3A and FIG. 3D are diagrams in the case where V-OB is 3 lines. 3 B is when V-OB is 5 lines, C in FIG. 3 is when V-OB is 2 lines, E in FIG. 3 and F in FIG. 3 are when V-OB is 4 lines Schematic diagram of screen showing detection of dark current value including smear in V-OB in one embodiment of the present invention or in the prior art FIG. 4A, FIG. 4D is a case where V-OB is 3 lines, 4B shows a case where V-OB is 5 lines, FIG. 4C shows a case where V-OB is 2 lines, FIG. 4E shows a case where F-FIG. 4F shows a case where V-OB is 4 lines. Schematic diagram of input / output of EM-CCD showing signal value including dark current in one embodiment of the present invention and in the prior art ((a) CMG amplitude at low / high multiplication, (b) Medium multiplication in CMG amplitude (C) When the CMG amplitude is increased or decreased, (d) When the CMG amplitude is increased or decreased) Schematic diagram of input / output during correction showing expansion of signal value including dark current according to one embodiment of the present invention ((a) at the time of CMG amplitude low / high multiplication, (b) at the time of medium multiplication of CMG amplitude, ( c) When CMG amplitude is multiplied by high and low (d) When accumulating when CMG amplitude is low and high Schematic diagram of corrected EM-CCD input / output showing the value obtained by subtracting the dark current from the expanded signal of one embodiment of the present invention ((a) When CMG amplitude is low / low multiplication, (b) Medium CMG amplitude (C) CMG amplitude high and high multiplication, (d) CMG amplitude low and low multiplication accumulation) Schematic diagram of incident light and CCD output level showing correction of proportionality of CCD output level by effective light source and V-OB smear level without white defect in one embodiment of the present invention Schematic diagram of incident light and CCD output level showing breakdown of proportionality between CCD output level due to light source of effective pixel and V-OB smear level with white defect in one embodiment of the present invention Schematic diagram of incident light and CCD output level showing approximation from CCD output level of effective pixel blooming light source and V-OB smear level without white defect in one embodiment of the present invention

  1A to 1R of an embodiment of the image pickup apparatus according to the present invention and the embodiment of the image pickup apparatus disclosed in Japanese Patent Application Laid-Open No. 2008-109639 of Japanese Patent Application Laid-Open No. 2008-109639 are as follows. There are an adder 104, a subtractor 105, a divider 106, a multiplier 107, an average unit 108, a reference memory unit 109, and a screen memory unit 110. A bit limiter 102 is a high-order bit discard or division unit or a white recompression unit that matches the number of input bits of the video signal processing circuit 7. For this reason, both an IC and a video signal processing IC for expanding the gradation range of a video by performing gradation correction separately for a high luminance part and a low luminance part in a commercially available pixel unit can be used for the video signal processing unit 7. If the number of internal processing gradations of the video signal processing unit 7 is large, the bit limiting unit 102 is on the output side of the video signal processing unit 7 and is generally adjusted to the tone number of the output video signal of 10 bits for transmission and 8 bits for industrial use. The compression correction unit 5, the dark current smear detection unit 6, the bit restriction unit 102, and the video signal processing unit 7 can be integrated in a video-only memory integrated DSP or FPGA.

  The operation of subtracting the dark current and the vertical smear of the pixel called white scratches, which are abnormally high in dark current and dark current level after the compression of the video signal according to the present invention is extended, is performed in one embodiment of the present invention and in the prior art. FIG. 5 is a schematic diagram of input / output of the EM-CCD showing a signal value including dark current, and FIG. 5 is a schematic diagram of input / output during correction indicating expansion of the signal value including dark current according to one embodiment of the present invention. A description will be given with reference to FIG. 6 and FIG. 7 which is a schematic diagram of the input / output of the post-correction EM-CCD showing the value obtained by subtracting the dark current from the expanded signal of one embodiment of the present invention.

In FIG. 5 of the schematic diagram of the input / output of the EM-CCD showing the signal value including the dark current, (a) When the CMG amplitude is low / low multiplication, the transfer capacity of the photodiode and the vertical transfer path is insufficient, resulting in unevenness in the screen High signal level is saturated. (B) Since the signal is multiplied after vertical transfer when the CMG amplitude is medium / multiple, the shortage of transfer capacity of the photodiode and vertical transfer path is compensated, and when combined with electronic cooling that reduces dark current, The adjustment range is expanded. Furthermore, due to variations in photodiode storage capacity, the dark current and video signal output from the CCD image sensor become high level and compressed as the gradation range of the image that was not uniform in the screen becomes uniform in the screen. Then, after decompression, the dark current and vertical smear of the pixel called white scratches are subtracted after dark current and dark current level are abnormally high.
(C) When the CMG amplitude is high and high, the electron multiplication is further increased, and the dark current and the vertical smear of the pixel called white scratches are high and compressed. The compression of the dark current, the vertical smear, and the video signal, which is called white scratches, where the dark current and the dark current level are abnormally high, is decompressed and the compression is subtracted from the decompressed video signal. By the way, (d) during accumulation when the CMG amplitude is low and low, the high signal level saturates unevenly within the screen.

  As shown in FIG. 6 of the schematic diagram of the input / output during correction showing the expansion of the signal value including dark current according to one embodiment of the present invention, the high-level signal value is expanded and linearized in accordance with the CMG amplitude. Then, if the dark current is subtracted, the linearization is performed as shown in FIG. 7 in the schematic diagram of the input / output of the post-correction EM-CCD indicating the value obtained by subtracting the dark current from the expanded signal in one embodiment of the present invention. Video signal is obtained. Thereafter, linear division or high level compression is performed to match the number of input bits of the video signal processing circuit.

  Next, an outline of an embodiment of the imaging apparatus according to the present invention is shown in FIGS. 1A to 1P of block diagrams showing an imaging apparatus having an overall configuration of an embodiment of the present invention and one embodiment of the present invention and the related art. This will be described with reference to FIG. 4A to FIG. 4F, which are schematic diagrams of screens showing detection of smear values in V-OB. Thereafter, the operation of some embodiments of the present invention, and the representative value detection flowchart of one embodiment of the present invention, as shown in FIGS. 2A to 2F of FIG.

  At the time of electron multiplication, the signal is multiplied after the vertical transfer, so that the shortage of the transfer capacity of the photodiode and the vertical transfer path is compensated, and when combined with electronic cooling that reduces the dark current, the gradation range of the image is expanded. Furthermore, due to variations in photodiode storage capacity, the dark current and video signal output from the CCD image sensor become high level and compressed as the gradation range of the image that was not uniform in the screen becomes uniform in the screen. Then, after the compression is expanded by the white expansion unit 101, the dark current and the vertical smear of the pixel called white scratches, which are abnormally high in dark current and dark current level, are subtracted. When the electron multiplication is further increased and the dark current, white scratches and vertical smear are at a high level and compressed, the dark current, white scratches and vertical smear are decompressed by the white stretcher 103 and then white stretched. 1 is subtracted from the decompressed video signal.

Also, the V-OB uses the fact that the H-OB portion of the V-OB is a dark current component of a pixel called a white flaw, in which a vertical smear and a horizontal smear are hardly mixed and a dark current level is abnormally high. The signal of the H-OB part of the V-OB is added and averaged at the average part 108, and the signal of the H-OB part of the V-OB is added and averaged at the average part 108 in the shielded reference state and stored in the reference memory part. Compared with the received signal, the dark current component due to temperature and electron multiplication and the dark current component change coefficient of the dark current component of the pixel, which is abnormally high, can be approximated in real time. Another method is to use that the Nth from the vertical horizontal minimum value of the V-OB is a dark current component in which the vertical smear and the horizontal smear hardly mix, and the Nth from the vertical horizontal minimum value of the V-OB. If it is detected and compared with the Nth from the vertical and horizontal minimum value of V-OB of the reference memory unit, the dark current component of the pixel called a white scratch due to abnormally high dark current or dark current level due to temperature and electron multiplication The coefficient of change can be approximated in real time. Therefore, the effective pixel OB difference standard obtained by subtracting the addition average of the signals of the H-OB portion of the V-OB from the dark current of the pixel called the white defect whose dark current or dark current level of the screen effective pixel of the screen memory unit is abnormally high. If the dark current signal is multiplied by the dark current due to temperature and electron multiplication, or the dark current component change coefficient of the pixel called the white scratch, the dark current level is abnormally high. A dark current component of a pixel called a white scratch whose level is abnormally high can be approximated.
In other words, the dark current and vertical smear component of the pixel called white scratches, where the dark current and dark current level of V-OB are abnormally high, and the white current and the dark current level of the effective pixel of the screen that is the difference from OB are abnormally high. Only the video signal of the screen effective pixel can be calculated by subtracting the dark current component of the pixel called a scratch.

1A to 1P, which are block diagrams showing an image pickup apparatus having an overall configuration according to an embodiment of the present invention, FIG. 1A to FIG. 1F show a representative value of V-OB by expanding high-intensity compression of an effective pixel signal. FIG. 1G to FIG. 1M show a case where the high-intensity compression of the effective pixel signal is expanded to subtract the representative value of V-OB and the dark current approximate value of the effective pixel. The difference between the representative value of V-OB including smear and the approximate value of dark current of effective pixels and the high-intensity compression of the total signal are expanded and subtracted.
As representative values of V-OB including smear, FIGS. 1A, 1G, 1M, 1N, 1O, and 1P show that V-OB is 3 lines or more and the second value from the minimum value (center of 3 lines). 1B and FIG. 1H are the cases where V-OB is 5 lines or more and the third value from the minimum value (the median value in 5 lines) is detected, and FIG. 1C and FIG. FIG. 1D and FIG. 1J show a case where the average value excluding the maximum value is detected when V-OB is 3 lines or more, and FIG. 1E and FIG. Is the case where the average value excluding the maximum and minimum values is detected when the V-OB is 4 lines or more. FIGS. 1F and 1L are the average values excluding the maximum value and the second largest value when the V-OB is 4 lines or more. Is detected. As a method for calculating the OB dark current, FIGS. 1A to 1M calculate the average of H-OB of V-OB, FIG. 1N calculates the minimum value of V-OB, and FIG. 1O shows the minimum of V-OB. The second is calculated from the value. The combination of the smear calculation method and the OB dark current calculation method is not limited to FIGS. 1A to 1P.

2A to 2F of the representative value detection flowchart of one embodiment of the present invention, FIG. 2A is a case where the second value is detected from the V-OB minimum value, and FIG. 2B is a third value from the V-OB minimum value. FIG. 2C shows a case where the V-OB minimum value is detected, FIG. 2D shows a case where the V-OB detects an average value excluding the maximum value, and FIG. 2E shows a V-OB maximum value and minimum value. FIG. 2F shows a case where the average value excluding the V-OB maximum value and the second largest value is detected.
1A to 1M of the block diagrams showing the image pickup apparatus having the overall configuration of an embodiment of the present invention are characterized in that the white value of the CCD image pickup element is excluded by the comparison unit and the line memory unit except for the maximum value or the second largest value. The effect of scratches is deleted.

  4A of FIG. 4 of the schematic diagram of the screen showing the detection of the smear value in the V-OB in one embodiment of the present invention or in the prior art and the V-OB in one embodiment or the prior art of the present invention. 3, A, B, C, D, E, and F in the schematic table diagram showing smear value detection correspond to FIGS. 1A, 1B, 1C, 1D, 1E, and 1F, respectively. . 1A and 1D have 3 lines for V-OB, FIG. 1B has 5 lines for V-OB, FIG. 1C has 2 lines for V-OB, and FIGS. 1E and 1F have 4 lines for V-OB. . 4A to 4F are schematic views of the screen, and the CCD image pickup surface is vertically and horizontally reversed from the screen.

  As shown in FIG. 3C, when there is a dark current of a pixel called white scratch in which the dark current level of the signal value 21 is abnormally high in two lines of V-OB, the average value is particularly large as 11.5. It can be seen that the error is particularly large in the correction (hereinafter, in this embodiment, the description will be continued assuming that the level of the maximum signal value that is determined as the dark current of the pixel called white scratch with an abnormally high dark current level is 21). As shown in FIG. 3A and FIG. 3D, if there are white scratches in the signal value 21 in the three lines of V-OB, the average value is 9, which is larger than the average value 3 excluding the median value 4 and the maximum value. It is a different value. As shown in E of FIG. 3 and F of FIG. 3, if there is a dark current of a pixel called white scratch in which the dark current level of the signal value 21 is abnormally high in 4 lines of V-OB, the average value becomes 8. The value is greatly different from the average value 3.67 excluding the maximum value. As shown in FIG. 3B, when there is a dark current of pixels called white scratches in which the dark current level of the signal value 21 is abnormally high in 5 lines of V-OB, the average value becomes 7, and the median 4 or It is a value greatly different from the average value 3.5 excluding the maximum value. Therefore, it can be seen that the average value has a large error in smear correction even if the number of V-OB lines is slightly increased. In FIG. 3A to FIG. 3F, the minimum value in this embodiment is 2, which is 1 to 2 smaller than the average value excluding the median value and the maximum value, but is larger than the conventional average value by 7 to 11.5. There is no. It can be seen that even when the number of V-OB lines is as small as two, the minimum value of the conventional V-OB has less smear correction error than the average value of five lines and is practical.

  1A to 1P, which are block diagrams illustrating an imaging apparatus having an overall configuration according to an embodiment of the present invention, 1 is an imaging apparatus, 2 is an optical system such as a lens that forms incident light, and 3 is incident from an optical system 2 A CCD image sensor such as an EM-CCD that converts the generated light into an electrical signal, 4 is a CDS that removes noise from the signal output from the CCD image sensor 3, an AGC that adjusts the dark current correction, and a gain of the signal, and a digital video signal FEP composed of ADC to convert to Vi (however, AGC may be used not included in FEP as shown in FIGS. 1C and 1E), 5 is an OB representative value signal from digital video signal Vi A white compression correction unit that subtracts and corrects smear components, 6 is an OB representative value detection unit that detects a V-OB representative value signal of the digital video signal Vi, and 21 to 23 are V of the digital video signal Vi. -OB line In comparison unit for comparing pixel by pixel, 71-76 is a line memory for storing the OB representative value, 11 is a subtracter for subtracting the representative value signal from the video signal. Reference numeral 7 denotes a composite video signal (hereinafter referred to as VBS) of NTSC (National Television System Committee) system or PAL (Phase Alternating by Line) system by performing various video processing on the signal Vm output from the detected white compression correction unit 5. An SDI (Serial Digital Interface) video signal or a video signal processing unit that converts the video signal into a predetermined video signal such as an HDTV SDI (HD-SDI) and outputs it. 8 is a drive for the EM-CCD 3 and gain control for electron multiplication. A CCD drive unit (or denoted as TG) for performing the above operation mainly includes a timing generator (TG) for generating a timing signal for driving the EM-CCD and a driver for driving the generated timing signal. 9 is a CPU (Central Processing Unit) for controlling each part in the imaging apparatus 1 (control lines from the CPU to each part are not shown) ). 10 is a digital AGC (D.AGC), in which the OB representative value signal is set in accordance with the amplification degree of the FEP AGC. Adjusts the amplification level of AGC itself. Reference numeral 14 denotes a cooling unit, which is a temperature sensor for detecting temperature, a Peltier element for cooling, a Peltier element driving circuit, a heat radiating fin, a fan, and a fan driving circuit, and cools the EM-CCD 3 to adjust the temperature.

Next, the operation of one embodiment of the present invention will be described with reference to FIGS. 1A to 1F. The EM-CCD 3 (or CCD 3) of the imaging device 1 photoelectrically converts incident light imaged on the light receiving surface by the optical system 2 with a photodiode to generate a signal charge, which is transferred vertically and then horizontally transferred. Electron multiplication and output to FEP4. The FEP 4 removes noise from the signal output from the EM-CCD 3, corrects the dark current component, amplifies the corrected signal, converts the signal to the digital video signal Vi, and outputs the digital video signal Vi to the white compression correction unit 5. The digital video signal Vi is sent to the OB representative value detection unit 6 via the white compression correction unit 5 and also sent to the subtractor 11 for signal processing to be described later. The OB representative value detection unit 6 compares the digital video signal Vi with the vertical pixel signals of the V-OB lines by the comparison units 21 to 23 and stores them in the line memories 71 to 76 in order of detection, and detects the OB representative value signal as a smear component. To do.
Alternatively, as in the embodiment shown in FIGS. 1D to 1F, the vertical pixel signal of the V-OB line that satisfies a predetermined standard is selected using the comparison units 21 and 22 and the line memories 72, 75, and 76, and the selection is made. The added vertical pixel signals may be added using the adding unit 13, the addition result may be stored in the line memory 71, and the averaging unit 12 may calculate an OB representative value signal as an average value.

The white compression correction unit 5 adjusts the OB representative value signal in accordance with the amplification degree of the AGC of the FEP. Amplified by the AGC 10, the subtractor 11 subtracts the amplified signal from the digital video signal Vi and outputs the digital video signal Vm to the video signal processing unit 7. The video signal processing unit 7 performs various video processing on the digital video signal Vm, converts it into a video signal Vo of a predetermined system, and outputs it.
Further, the CCD drive unit (TG) 8 outputs a signal for driving the EM-CCD 3 in accordance with a control signal (not shown) output from the CPU 9. In the embodiment shown in FIGS. 1C and 1E, the FEP 4 has no AGC, so that the white compression correction unit 5 performs the digital AGC after subtracting the OB representative value signal from the digital video signal Vi.
Further, in the embodiment shown in FIGS. 1A to 1F, the FEP does not include AGC, and the smear correction unit D.D. There are examples in which the arrangement location of AGC is different, examples in which the number of bits of the digital signals Vi and Vm and the number of bits of the OB representative value signal are different, examples in which the configurations of the comparison unit and the line memory unit are different, etc. Is merely an example and various configurations may be applied.

Next, the vertical smear signal detection and correction operation will be described with reference to FIGS. 1A-1F, 2A-2F, A-3 in FIG. 3, F in FIG. 4, and A in FIG.
First, the embodiment shown in FIGS. 1A, 2A, 3A, and 4A will be described. The CPU 9 sets the upper limit value of the minimum value signal and the upper limit value of the second smallest signal in the line memory units 72 and 73, respectively. Here, as these upper limit values, for example, values obtained by quantifying the luminance of the signal may be used (each value described below is also quantified by the same standard). The comparison unit 21 compares the upper limit value stored in the line memory unit 72 with the pixel value of the video signal of the first line in the V-OB area (hereinafter referred to as V-OB1) between the pixels, and the value is small. The other signal (video signal of V-OB1) is stored in the line memory unit 72 as a minimum value signal of each pixel (steps 21 and 22). The comparison unit 21 compares the pixel value of the video signal of V-OB2 with the minimum signal value of the line memory unit 72 between the pixels, and the signal having the smaller value is stored in the line memory unit 72 for each pixel. Is stored as a minimum value signal. The signal having the larger value is sent to the comparison unit 22. The comparison unit 22 compares the value of the larger signal with the upper limit value stored in the line memory unit 73 as the second smallest signal between the pixels, and compares the smaller signal with the second smallest value of each pixel. The signal is stored in the line memory unit 73 as a signal (step 23). Similarly, the comparison unit 21 compares the pixel value of the V-OBN video signal of the Nth line (N is a natural number of 3 or more) with the minimum value of the memory unit 72, and the smaller value is obtained. Is stored in the line memory unit 72 as a minimum value signal of each pixel. The signal having the larger value is sent to the comparison unit 22 as a comparison 1 signal for each pixel (step 24). The comparison unit 22 compares the value of the second smallest signal and the value of the comparison 1 signal between the pixels, and stores the signal having the smaller value in the line memory unit 73 as the second smallest signal of each pixel. (Step 25). When the comparison unit 22 finishes the last V-OB comparison process, the line memory unit 73 outputs the second smallest signal to the smear correction unit 5 as an OB representative value signal for smear correction (step 26). The value detection process ends (step 27).

  Next, the embodiments shown in FIGS. 1B, 2B, 3B, and 4B will be described. The CPU 9 sets an upper limit value of the minimum value signal, an upper limit value of the second smallest signal, and an upper limit value of the third smallest signal in the line memory units 72, 73, and 74, respectively. The comparison unit 21 compares the upper limit value stored in the line memory unit 72 with the pixel value of the V-OB1 video signal between the pixels, and the smaller value of the signal (V-OB1 video signal). Is stored in the line memory unit 72 as a minimum value signal (steps 21 and 28). The comparison unit 21 compares the value of the minimum signal and the value of the pixel of the video signal of V-OB2 between the pixels, and the line memory unit 72 uses the signal having the smaller value as the signal of the minimum value of each pixel. (Step 29). The comparison unit 22 compares the value of the larger signal with the upper limit value stored in the line memory unit 73 as the second smallest signal of each pixel, and compares the signal having the smaller value second. A small signal is stored in the line memory unit 73 (step 29). The comparison unit 21 compares the value of the signal stored in the line memory unit 72 and the value of the video signal of the V-OB3 between the pixels, and uses the signal having the smaller value as the minimum value signal of each pixel. Store in the memory unit 72. The signal having the larger value is sent as a comparison 1 signal to the comparison unit 23 (step 30). The comparison unit 22 compares the value of the second smallest signal stored in the line memory unit 73 and the signal of comparison 1 between the pixels, and the signal having the smaller value is the second smallest signal of each pixel. Is stored in the line memory unit 73. The comparison unit 23 compares the signal having the larger value with the upper limit value stored in the line memory unit 74 as the third smallest signal among the pixels, and compares the signal having the smaller value to the third value of each pixel. A small signal is stored in the line memory unit 74 (step 31). Similarly, the pixel value of the V-OBN video signal of the Nth line (N is a natural number of 4 or more) and the minimum value of the line memory unit 72 are compared between the pixels, and the signal having the smaller value is compared with each signal. The signal is stored in the line memory unit 72 as a signal of the minimum value of the pixel. The signal having the larger value is sent to the comparison unit 22 as a comparison 1 signal for each pixel (step 24). The comparison unit 22 compares the value of the second smallest signal and the value of the comparison 1 signal between the pixels, and stores the signal having the smaller value in the line memory unit 73 as the second smallest signal of each pixel. To do. The signal having the larger value is sent to the comparison unit 23 as a comparison 2 signal for each pixel (step 32). The comparison unit 23 compares the value of the third smallest signal and the value of the comparison 2 signal in each pixel, and stores the signal having the smaller value in the line memory unit 74 as the third smallest signal of each pixel. (Step 33). When the comparison of the last V-OB is completed in the comparison unit 23, the line memory unit 74 outputs the third smallest signal to the smear correction unit 5 as the smear correction OB representative value signal (step 34). The signal detection process ends (step 27).

  Further, the embodiments shown in FIGS. 1C, 2C, 3C, and 4C will be described. The CPU 9 sets an upper limit value of the minimum value signal in the line memory unit 72. The comparison unit 21 compares the upper limit value and the pixel value of the V-OB1 video signal between the pixels, and sets the signal having the smaller value (V-OB1 video signal) as the minimum value signal as a line memory unit. 72 (steps 21 and 35). The comparison unit 21 compares the value of the minimum value signal and the value of the pixel of the V-OB2 video signal between the pixels, and stores the signal having the smaller value in the line memory unit 72 as the minimum value signal. (Step 36). Similarly, the comparison unit 21 compares the pixel value of the video signal of the V-OBN of the Nth line (N is a natural number of 3 or more) and the value of the minimum signal value between the pixels, and the smaller value is obtained. Is stored in the line memory unit 72 as a minimum value signal (step 37). When the comparison unit 21 finishes the last V-OB comparison process, the line memory unit 72 outputs the minimum value signal to the smear correction unit 5 as the smear correction OB representative value signal (step 38). The detection process ends (step 27).

  The embodiments shown in FIGS. 1D, 2D, 3D, and 4D will be described. The CPU 9 sets the value of the line memory unit 71 to 0 and the value of the line memory unit 75 to the lower limit value of the signal. The comparison unit 21 compares the lower limit value and the value of the V-OB1 video signal between the pixels, and uses the signal having the larger value (V-OB1 video signal) as the maximum value signal of each pixel in the line memory. Stored in the unit 75 (steps 21 and 39). The comparison unit 21 compares the maximum value signal and the pixel value of the V-OB2 video signal between the pixels, and stores the signal having the larger value in the line memory unit 75 as the maximum value signal. The adding unit 13 adds and stores the signal having the smaller value in the line memory unit 71 as an intermediate value (step 40). Similarly, the comparison unit 21 compares the pixel value of the video signal of the V-OBN (N is a natural number of 3 or more) of the Nth line with the maximum value signal between the pixels, and the signal having the larger value is compared. Is stored in the line memory unit 75 as a maximum value signal. The adding unit 13 adds and stores the signal having the smaller value in the line memory unit 71 as an intermediate value (step 41). When the comparison unit 21 finishes the last V-OB comparison process, the line memory unit 71 outputs the value added and stored in the averaging unit 12. The averaging unit 12 attenuates the intermediate value signal to 1 / (N−1), calculates the average value, and outputs the average value to the smear correction unit 5 as an OB representative value signal for smear correction (step 42). The detection process ends (step 27).

  Further, the embodiments shown in FIGS. 1E, 2E, 3E, and 4E will be described. The CPU 9 sets the value of the line memory unit 71 to 0, sets the value of the line memory unit 72 to the upper limit value of the signal, and sets the value of the line memory unit 75 to the lower limit value of the signal. The comparison unit 21 compares the lower limit value with the pixel value of the video signal of V-OB1 between the pixels, and uses the signal with the larger value (V-OB1 video signal) as the signal of the maximum value of each pixel. It memorize | stores in the line memory part 75 (steps 21 and 43). The comparison unit 21 compares the maximum value signal and the pixel value of the V-OB2 video signal between the pixels, and stores the signal having the larger value in the line memory unit 75 as the maximum value signal of each pixel. To do. The signal having the smaller value is sent to the comparison unit 22 as a signal of the minimum value of each pixel. The comparison unit 22 compares the signal having the smaller value with the upper limit value stored in the line memory unit 72 between the pixels, and uses the signal having the smaller value as the signal of the minimum value of each pixel. (Step 44). The comparison unit 21 compares the value of the maximum signal stored in the line memory unit 75 with the value of the pixel of the video signal of V-OB3 for each pixel, and the signal with the larger value is the signal with the maximum value. Is stored in the line memory unit 75. The comparison unit 21 sends the signal having the smaller value to the comparison unit 22 as a signal of comparison 1 (step 45). The comparison unit 22 compares the value of the minimum value signal and the value of the comparison 1 signal between the pixels, stores the smaller value signal in the line memory unit 72 as the minimum value signal, and the value is larger. The other signal is added and stored as an intermediate value in the line memory 71 via the adder 13 (step 46). Similarly, the comparison unit 21 compares the pixel value of the video signal of the V-OBN of the Nth line (N is a natural number of 4 or more) and the value of the maximum signal value between the pixels, and the larger value is obtained. Is stored in the line memory unit 75 as a maximum value signal, and the signal having the smaller value is sent to the comparison unit 22 as a comparison 1 signal (step 47). The comparison unit 22 compares the value of the minimum value signal and the value of the comparison 1 signal between the pixels, stores the smaller value signal in the line memory unit 72 as the minimum value signal, and the value is larger. The other signal is added and stored as an intermediate value in the line memory 71 via the adder 13 (step 48). When the comparison unit 22 finishes the last V-OB comparison process, the line memory unit 71 outputs the value added and stored in the averaging unit 12. The averaging unit 12 attenuates the intermediate value signal to 1 / (N−2) to calculate an average value, and outputs the average value to the smear correction unit 5 as an OB representative value signal for smear correction (step 49). The signal processing ends (step 27).

  Further, the embodiments shown in FIGS. 1F, 2F, 3F, and 4F will be described. The CPU 9 sets the value of the line memory unit 71 to 0 and the values of the line memory units 75 and 76 to the lower limit value of the signal. The comparison unit 21 compares the lower limit value with the pixel value of the video signal of V-OB1 between the pixels, and uses the signal having the larger value (V-OB1 video signal) as the maximum value signal as a line memory unit. 75 (steps 21 and 50). The comparison unit 21 compares the maximum signal value and the pixel value of the V-OB2 video signal between the pixels, and stores the signal having the larger value in the line memory unit 75 as the maximum value signal. . The signal having the smaller value is sent to the comparison unit 22 as the second largest signal of each pixel. The comparison unit 22 compares the signal having the smaller value with the lower limit value stored in the line memory unit 76 between the pixels, and sets the signal having the smaller value as the second largest signal of each pixel. (Step 51). The comparison unit 21 compares the value of the maximum signal stored in the line memory unit 75 with the value of the pixel of the V-OB3 video signal between the pixels, and compares the signal having the larger value with the maximum value. The signal is stored in the line memory unit 75 as a signal. The comparison unit 21 sends the signal having the smaller value to the comparison unit 22 as a signal of comparison 1 (step 45). The comparison unit 22 compares the value of the second largest signal and the value of the comparison 1 signal in each pixel, and stores the signal having the larger value in the line memory unit 75 as the second largest signal. The smaller signal is added and stored in the line memory 71 via the adder 13 as an intermediate value (step 52). Similarly, the comparison unit 21 compares the pixel value of the video signal of the V-OBN of the Nth line (N is a natural number of 4 or more) and the value of the maximum signal value between the pixels, and the larger value is obtained. Is stored in the line memory unit 75 as a maximum value signal, and the signal having the smaller value is sent to the comparison unit 22 as a signal for comparison 1 (step 47). The comparison unit 22 compares the value of the second largest signal and the value of the comparison 1 signal between the pixels, and stores the signal having the larger value in the line memory unit 75 as the second largest signal. Is added and stored in the line memory 71 via the adder 13 as an intermediate value (step 53). When the comparison unit 22 finishes the last V-OB comparison process, the line memory unit 71 outputs the value added and stored in the averaging unit 12. The averaging unit 12 attenuates the intermediate value signal to 1 / (N−2), calculates the average value, and outputs it to the smear unit 5 as an OB representative value signal for smear correction (step 49). The detection process ends (step 27).

  Further, the embodiments shown in FIGS. 1B, 2B, 3B, and 4B show a method of using the third value from the minimum value of each vertical pixel signal as a representative value, and the dark current level is Not only is there no influence of white scratches on pixels called abnormally high white scratches, but there is almost no influence of black scratches, which are pixel defects with extremely low dark current, making it difficult to use expensive CCD image sensors that are strictly selected Applications Especially suitable for EM-CCD. Further, since there is almost no influence of white scratches and black scratches, a circuit for detecting the presence or absence of vertical smear generation can be omitted. A circuit for truncating the low-level vertical smear correction signal that prevents black vertical streak due to vertical smear detection error can also be omitted. In the embodiment shown in FIG. 1B, the signal Vm input to the video signal processing unit 7 after subtracting the OB representative value signal from the signal Vi is set to 10 bits, and the low-priced video signal processing unit 7 that is often used for monitoring purposes. It matches the number of input bits. However, in order to maintain the accuracy of vertical smear correction, the number of output bits of FEP4 is 14 bits.

1C, FIG. 2C, FIG. 3C, and FIG. 4C are other embodiments of the present invention, and show a method of calculating the minimum value of each vertical pixel signal as a V-OB representative value. Thus, the vertical smear correction signal can be stored for one line, and the integration scale is smaller than that of the conventional example. The present embodiment is suitable for an HDTV CCD image sensor having a small number of V-OB lines and few black scratches. Furthermore, although there is no AGC, vertical smear correction is highly accurate using 16-bit FEP. Here, if the comparison units 22 and 23 and the line memories 72 and 73 are omitted in FIGS. 1A and 1B, and the operation of FIG. 2C is performed, a CCD image pickup device of an HDTV having a small number of V-OB lines and few black scratches can be obtained. It becomes the high sensitivity application used.
Further, the embodiments shown in FIGS. 1D, 2D, 3D, and 4D show a method of calculating an average value excluding the maximum value when V-OB is 3 lines or more, and there are many white scratches. It is suitable for a CCD image sensor with a large number of V-OB lines but few black scratches.
1E, FIG. 2E, FIG. 3E, and FIG. 4E show a method in which the average value excluding the maximum value and the minimum value is used as a representative value when V-OB is 4 lines or more. 1E is A / D-converted to 22 bits, and it is easy to correct the dark current of the CCD image sensor. In addition, the CCD image sensor with many white and black defects and a large number of V-OB lines can be operated with high sensitivity. Suitable for
In the embodiments shown in FIGS. 1F, 2F, 3F and 4F, the average value excluding the maximum value and the second largest value when V-OB is 4 lines or more is a representative value. It is particularly suitable for applications in which a CCD image pickup device having a large number of V-OB lines is operated with high sensitivity.

  In V-OB, in order to avoid deterioration in correction accuracy due to vertical dark portion unevenness with a large fluctuation at the beginning of the screen, a video signal output from a V-OB area pixel below the screen that is output after the effective pixel is corrected for unevenness in the vertical dark portion. The accuracy of smear correction is better when the representative value is calculated. However, since smear correction is delayed by one screen (about 17 m (1/60) second), it is not practical. Therefore, A / D conversion to 14 bits is performed, and vertical dark spot unevenness correction with a large fluctuation at the beginning of the screen is performed with high accuracy, and the video signal output from the V-OB area pixel on the screen that is output before the effective pixel is vertical. If the representative value is calculated after correcting the dark portion unevenness, the smear correction can be performed simultaneously with the effective pixel output, and there is no delay.

  In addition, FIG. 1N and FIG. 1P calculate the approximate value of dark current multiplication using the minimum value when V-OB is 2 lines or more, subtract the V-OB minimum value and the dark current of the effective pixel, FIG. 3 is a block diagram illustrating an imaging apparatus having an overall configuration according to an embodiment of the present invention when decompressing high-intensity compression in accordance with a minimum value of OB and a dark current of effective pixels. In FIG. 1N, the amount of offset of the CDS reference voltage such as CCD GND, OB CLAMP LOOP, or BLACK LEVEL CLAMP is secured more than half of the CDS input signal amplitude, A / D of 12 bits or more, video signal processing circuit of 12 bits or more, and all A dark current reference value is stored in all the pixel memories, a second value is calculated as a smear signal from the minimum value of the vertical pixel signals of the VOBs of the plurality of lines, and the dark current of the VOB is calculated. The image of the current reference amount is offset by the amount of AGC amplification D. AGC attenuated to the current reference amount of the VOB dark current, such as CCD GND, OB CLAMP LOOP or BLACK LEVEL CLAMP. The current reference amount of the VOB dark current is subtracted from the signal, and the ratio between the current representative value of the VOB dark current and the representative value of the reference VOB dark current is used as an approximation of the dark current multiplication. Effective pixel dark current and dark The difference dark current from OB is calculated from the approximate value of the current multiplication, and the sum of the smear signal is subtracted from the subtraction of the current reference amount of the VOB dark current from the video signal, and the subtracted dark current is calculated. Based on the dark current difference between the current reference amount and OB and the OB representative value including smear, the high luminance of the video signal is expanded and signal processing is performed. Assume that the decompressed effective bit tone video signal in FIG. The response for offsetting the reference voltage of the gradation CDS may be a screen cycle, and the bit gradation between the A / D and the video signal processing circuit is 12 bits or more. If the dark current unevenness of the EM-CCD is reduced, the bit gradation can be 10 bits or more, and even if the dark current, white scratches and vertical smear are at a high level and compressed, the gradation range of the image is expanded.

  The difference between FIG. 1P and FIG. 1N is that the dark current detection and correction from the OB is divided into the inside of the FEP 121, the smear dark current detection unit 5, and the white compression correction unit 6, and an adder 112, a divider 113, If the reference memory unit 114 is added and the dark current multiplication amount of the OB dark current detailed correction detected by the divider 113 is added to the dark current multiplication amount by the adder 112, the operation becomes complicated. This is that the video signal gradation (number of bits) of the FEP 121, the smear dark current detection unit 5, the white compression correction unit 6, and the video signal processing circuit 7 is 10 bits or more. The adders 111 and 112, the divider 113, and the reference memory unit 114 in FIG. 1O are omitted, and the dark current subtraction of the effective pixels and the dark current correction inside the FEP are ignored, ignoring the dark current correction inside the FEP. If the white extension is performed, the correction accuracy is lowered, but the operation is simplified.

Further, FIG. 1O calculates an approximate value of dark current multiplication using the second from the minimum value of V-OB, subtracts the second and the dark current of the effective pixel from the minimum value of V-OB, and V-OB. It is a block diagram which shows the imaging device of the whole structure of one Example of this invention in the case of extending | stretching high-intensity compression according to the dark current of the 2nd and effective pixel from the minimum value. In FIG. 1O, the amount of offset of the CDS reference voltage, which is variable in pixel units such as CCD GND, is secured by more than half of the CDS input signal amplitude, A / D of 10 bits or more, video signal processing circuit of 10 bits or more, and all pixel memory The dark current reference value is stored in all the pixel memories, and the ratio of the current total amount of dark current of the VOB and the total dark current amount of the reference VOB is used as an approximation of dark current multiplication, CCD GND, etc. Offset the CDS reference voltage, which is variable in pixel units, and subtract the current approximate value of the dark current and smear of all pixels from the video signal, then add the current approximate value of the dark current and smear of all pixels. In consideration of compression, the video signal processing circuit performs signal processing on the basis of the current approximate value of the dark current of all pixels and the total amount of smear. Assume that the decompressed effective bit tone video signal in FIG. The CDS reference voltage response requires pixel units, but no video subtraction is required, and the bit gradation between the A / D and the video signal processing circuit is 10 bits or more, and dark current, white scratches and vertical smear are high. Even if the level is compressed, the gradation range of the video is expanded.
Further, since the dark current of each pixel of the effective pixel is calculated from the OB dark current and the dark current of each pixel of the effective pixel is subtracted from the video signal of each pixel of the effective pixel, the dark current unevenness is eliminated and the high electron increase is eliminated. Interdigital noise due to current unevenness during doubling or long-time storage is eliminated, effective sensitivity is improved, and the electron multiplication factor can be controlled low. If the electron multiplication factor is low, the deterioration of the electron multiplication factor with time is small, and the power consumption of the cooling unit 14 is small.

  At the time of electron multiplication, the signal is multiplied after the vertical transfer, so that the shortage of the transfer capacity of the photodiode and the vertical transfer path is compensated, and when combined with electronic cooling that reduces the dark current, the gradation range of the image is expanded. Furthermore, due to variations in photodiode storage capacity, the dark current and video signal output from the CCD image sensor become high level and compressed as the gradation range of the image that was not uniform in the screen becomes uniform in the screen. Once the compression is extended, dark current, white scratches and vertical smear are subtracted, or dark current, white scratches and vertical smear are subtracted, and then the high level is expanded based on the dark current, white scratches and vertical smear subtracted. To do. When the electron multiplication is further increased and the dark current, white scratches and vertical smear are at a high level and compressed, the dark current, white scratches, vertical smear and video signal compression are expanded to expand the compressed video signal. Subtract from dark current, white scratches, or vertical smear, and then subtract from dark current, white scratches, or vertical smear to take into account high-intensity compression of dark current, white scratches, or vertical smear. Extend level.

  As a result, even when using an EM-CCD imaging device with many dark currents, white scratches and vertical smears and a small number of lines in the V-OB pixel part, and EM-CCDs with many vertical smears and white scratches, a stable image can be obtained. The compression of the signal is expanded, and a reduction in the gradation range of the image of the image signal output from the EM-CCD is electronically corrected to reduce an error due to white flaw and vertical smear correction. In other words, the grayscale range is effectively expanded by reducing the whiteout of the video signal or the false signal near the black level.

  Although the image pickup apparatus using the EM-CCD has been described in detail above, the present invention is not limited to the image pickup apparatus described here, and can be widely applied to other image pickup apparatuses using other CCDs. It goes without saying that it can be applied.

  As another embodiment according to the present invention, first, it will be described that the CCD output level of a part of the vertical smear becomes a white state of a supersaturation level called blooming due to the abnormally strong supersaturated incident light described in the background art. The incident light that is the source of smear and blooming is hereinafter referred to as the light source. The sum of the V-OB smear level and the dark current of the V-OB or the dark current of a pixel called a white scratch with an abnormally high dark current level is the minimum value (V-OBmin) of the vertical pixels (columns) of the V-OB. An embodiment of the present invention in which the representative value of V-OB is subtracted by expanding the high-intensity compression of the signal of the effective pixel as an imaging method that is approximately detected in FIG. FIG. 1Q and FIG. 1R of the block diagrams showing the image pickup apparatus having the overall configuration of FIG. 1 and incident showing the correction of the proportionality of the CCD output level by the effective pixel light source and the V-OB smear level without white flaws in one embodiment of the present invention. FIG. 8A is a schematic diagram of the light and the CCD output level, and the incident light and the CCD output level showing breakdown of the proportionality of the CCD output level by the light source of the effective pixel and the V-OB smear level with white scratches in one embodiment of the present invention. 8B of the schematic diagram of the present invention and the present invention 8C of the schematic diagram of the incident light and the CCD output level showing an approximation from the CCD output level by the blooming light source of the effective pixel and the V-OB smear level free from white flaws in one embodiment of FIG.

  As described in the background art, the vertical transfer path becomes supersaturated with excessive charge generated by the photodiode and overflowing the vertical transfer path with saturated incident light that is stronger than the CCD output of the effective pixel reaches the supersaturation level. The lower end of the screen of the image with strong incident light becomes a white state called blooming with a supersaturation level higher than the vertical smear. In addition, the supersaturated incident light that becomes the CCD output video signal that is oversaturated and reaches the limit level has a supersaturation level higher than that of the vertical smear in order from the bottom of the screen of the image of the strong supersaturated incident light as the incident light intensity increases. The horizontal transfer path also becomes supersaturated due to abnormally strong supersaturated incident light, and the vertical smear at the top of the screen sinks, and white streaky horizontal smears are revealed in the horizontal direction. descend. When the intensity of abnormally strong supersaturated incident light is further increased, white spreads over the entire screen.

  In the block diagram showing the imaging apparatus having the overall configuration of one embodiment of the present invention, the difference between FIGS. 1H and 1Q, and FIGS. 1L and 1R is that the white expansion unit 101 is moved to the input of the white compression correction unit 5. , The white extension unit 103 becomes unnecessary, and the comparison unit 115 is added, and the maximum value of the comparison unit 115 is supplied to the CPU 9 as a supersaturation signal. Further, the gradation of FEP4 may be 10 bits because the white expansion unit 101 is moved to the input of the white compression correction unit 5. 1A to 1G, FIG. 1I, FIG. 1J, FIG. 1K, and FIG. 1M to FIG. 1O, the white expansion unit 101 is moved to the input of the white compression correction unit 5 to eliminate the need for the white expansion unit 103, as described above. And the maximum value of the comparison unit 115 may be supplied to the CPU 9 as a supersaturation signal. Although not shown, in the block diagram showing the imaging apparatus having the overall configuration of one embodiment of the present invention, the CPU 9 monitors and controls the state of each part of the imaging apparatus 1 and the optical system 2.

  In FIG. 1Q and FIG. 1R of the block diagrams showing the image pickup apparatus having the overall configuration of one embodiment of the present invention, when the supersaturation signal exceeds a predetermined value, the CPU 9 reduces the optical aperture of the optical system 2 or attenuates the optical ND filter. Increasing the rate to reduce the amount of incident light, or reducing the effective sensitivity with the electronic shutter by the CCD drive unit (TG) 8, prevents the supersaturated state between the vertical transfer path and the horizontal transfer path. The sensitivity is kept constant by increasing the AGC of FEP4 or increasing the CMG voltage of EM-CCD3 to increase the electron multiplication factor. The description of the configuration and operation of the same parts as in FIGS. 1H and 1L is omitted.

8A, FIG. 8B, and FIG. 8C showing the CCD output level and the V-OB smear level by the light source of the effective pixel in one embodiment of the present invention, (a) is the non-multiplication of EM-CCD. Sometimes (b) is at low multiplication of EM-CCD, IT-CCD and FT-CCD, and (c) is at high multiplication of EM-CCD.
8A, 8B, and 8C, the horizontal axis is incident light, the vertical axis is CCD output, and the lower left straight line and curve are minimum values (V-OBmin) of vertical pixels (columns) of V-OB. The CCD output of the total value of the dark current of the pixels called white scratches, which is the approximate detection of the V-OB smear level and the dark current of V-OB or the dark current level is abnormally high. This is a CCD output by incident light (hereinafter referred to as a light source) that becomes a source of smear and blooming. The intersection with the vertical axis is a dark current in FIGS. 8A and 8C, and an abnormally large dark current with white defects, which is an abnormally large dark current in FIG. 8B.

  In one embodiment of the present invention, the V-OB smear level and V-OB are detected approximately by the CCD output from the effective pixel light source and the minimum value (V-OBmin) of the vertical pixel (column) of V-OB. 8A, FIG. 8B, and FIG. 8C, which are schematic diagrams showing dark current or the total value of dark current of pixels called white scratches with abnormally high dark current levels, the CCD output level and white scratches of the effective pixel light source. The ratio of the V-OB smear level that is not present is constant, such as 80 dB, if the CCD output saturation is linearly expanded by white extension. As shown in FIG. 8A (c) of the schematic diagram, even if the CCD output of the effective pixel reaches the saturation level, the saturated incident light level can be approximately calculated by white expansion of the CCD output of the effective pixel.

As shown in (b) and (c) of FIG. 8B of the schematic diagram, the amount of change in the CCD output of the effective pixel is small with the abnormally strong supersaturated incident light that becomes the CCD output signal of the effective pixel that is further oversaturated and reaches the limit level. Even if white is stretched, the saturated incident light level is not effective due to many approximation errors. Approximate detection of V-OBmin and V-OB smear level and dark current of V-OB or a dark current level of a pixel called abnormally high is a constant approximation calculation such as 80 dB from the sum of dark currents of pixels called white scratches. The supersaturated incident light level of the effective pixel can be approximated with high accuracy.
As shown in Fig. 8C (c) of the schematic diagram, if the CCD output signal of V-OBmin reaches white level even if the CCD output signal level of V-OBmin becomes saturated, CCD output of V-OBmin expanded white. The supersaturated incident light level that is strong against abnormal effective pixels can be approximated by a constant approximation such as 80 dB from the signal.

  Therefore, the vertical smear immediately before the supersaturation is approximately detected from the minimum value V-OBmin of the vertical pixel of the white expanded V-OB signal, and the maximum value of the vertical smear is detected by the comparator, and the AGC, electron multiplication factor, When the vertical transfer path determined by (1) exceeds the first predetermined value that is in a supersaturated state, the optical aperture of the optical system such as a lens is stopped and the AGC in the FEP is increased or the CMG voltage of the EM-CCD is increased to increase the electron. If the sensitivity is made constant by increasing the magnification, it is possible to prevent the white state of the supersaturated level of the image of the supersaturated incident light image, the sinking of the upper part of the screen, and the horizontal smear. Even if it is not the minimum value V-OBmin, the value of the N-th (N is a natural number) value from the minimum value of each vertical pixel (column) signal of V-OB, and the value not more than the M-th (M is a natural number) value from the maximum value Alternatively, at least one of the representative value signals calculated from the average value or the maximum value of the Mth value or less may be calculated. If the optical diaphragm of the optical system such as a lens reaches the limit on the diaphragm opening side and the incident light quantity cannot be reduced by the optical diaphragm, and the horizontal transfer path becomes oversaturated, the electronic shutter will be effective. If the sensitivity is lowered and the AGC in the FEP is increased, the white state of the supersaturated level of the image of the supersaturated incident light image, the subsidence at the top of the screen, and the horizontal smear can be reduced.

In particular, when the optical diaphragm of an optical system such as a lens reaches the limit on the diaphragm opening side and the amount of incident light cannot be reduced by the optical diaphragm, and the horizontal transfer path becomes oversaturated, the electronic shutter will If the effective sensitivity is lowered and the VGA in the FEP is increased, the white state of the supersaturated image in the vertical transfer path and the horizontal transfer path due to the supersaturated incident light, the sinking in the upper part of the screen, and the horizontal smear can be reduced. When the sensitivity is lowered by sweeping signal charge electrons of the photodiode of the CCD image pickup device to the overflow drain (using an electronic shutter), the vertical smear is lowered at a constant level, and the vertical smear is relatively To increase. However, the vertical smear is not noticeable because it is subtracted by the subtractor 11 of the white compression correction unit 5.
When the AGC is increased or the electron multiplication factor is increased, the noise increases, but the vertical smear at the top of the screen sinks, and it is possible to prevent the white streak-like horizontal smear from becoming apparent in the horizontal direction. If the intensity of the abnormally strong supersaturated incident light is further increased, it is possible to reliably prevent the supersaturated white from spreading over the entire screen.

  That is, it is possible to effectively expand the gradation range of the video signal such as subsidence below the black level or reducing white at the supersaturation level. The detection of the supersaturated incident light may include a pixel called a black flaw among the V-OB pixels in which the dark current is abnormally small. That is, supersaturated incident light may be detected from a signal including the minimum value of each vertical pixel (column) signal of a plurality of lines of V-OB.

  Although the image pickup apparatus using the EM-CCD has been described in detail above, the present invention is not limited to the image pickup apparatus described here, and can be widely applied to other image pickup apparatuses using other CCDs. It goes without saying that it can be applied.

1: imaging device, 2: optical system, 3: EM-CCD, 4: FEP,
5: White compression correction unit, 6: Dark current smear detection unit, 7: Video signal processing unit,
8: CCD drive unit (TG), 9: CPU, 10: Variable gain unit (D.AGC)
11, 105: subtractor, 12: coefficient part, 13, 104, 111, 112: adder,
14: Cooling unit, 21, 22, 23, 115: Comparison unit, 71-76: Line memory unit,
101, 103: white extension part,
102: bit limiter (higher-order bit discard-division unit-white recompression unit)
106, 113: Divider, 107: Multiplier, 108: Average part,
109, 114: reference memory unit, 110: screen memory unit

Claims (4)

A solid-state imaging device, a first acquisition unit that acquires video signals output from effective pixels on the light-receiving surface of the solid-state imaging device, and signals output from light-shielded pixels above or below the light-receiving surface of the solid-state imaging device In a solid-state imaging device having a second acquisition unit to acquire,
First means for storing a signal output from the effective pixel acquired by the first acquisition unit at the time of light shielding and a signal output from the light-shielded pixel acquired by the second acquisition unit at the time of light shielding; The average value of values equal to or less than the Mth (M is a natural number) value from the maximum value of the signals output from the V-OB H-OB pixels on the upper and lower V-OB lines acquired by the second acquisition unit. and means for calculating a, H-OB of the upper and lower V-OB multiple lines for storing a reference value of the dark current to the first means for the storage and shielding acquired by the second acquisition unit The average value of the values equal to or less than the Mth (M is a natural number) value is calculated from the maximum value of the signal output from each pixel, and from the V-OB H-OB pixels at the upper and lower portions of the shaded lines. Average value of values less than M (M is a natural number) from the maximum value of the output signal The ratio between the reference value of the average values of the upper and M (M is a natural number) from the maximum value at the bottom of the V-OB signals output from the pixels of the H-OB-th value following values of a plurality of lines that the shielding the calculated approximate dark signal over the reference value of the dark current of the first means for the storage,
The output of the solid-state imaging device a difference signal between the first signal extended high levels of approximation dark current signal the calculated high extended signal of the video signal output from the effective pixels obtained by the obtaining unit An imaging method characterized by being used for a video signal . A solid-state imaging device, a first acquisition unit that acquires video signals output from effective pixels on the light-receiving surface of the solid-state imaging device, and signals output from light-shielded pixels above or below the light-receiving surface of the solid-state imaging device In a solid-state imaging device having a second acquisition unit to acquire,
First means for storing a signal output from the effective pixel acquired by the first acquisition unit at the time of light shielding and a signal output from the light-shielded pixel acquired by the second acquisition unit at the time of light shielding; Means for calculating the Nth (N is a natural number) value from the minimum value of the signals output from the V-OB H-OB pixels of the upper and lower shaded lines acquired by the second acquisition unit; a, it is outputted from the H-OB pixels of upper and lower V-OB multiple lines for storing a reference value of the dark current to the first means for the storage and shielding acquired by the second acquisition unit The Nth (N is a natural number) value is calculated from the minimum value of the signal, and N (N is the minimum value of the signal output from the V-OB H-OB pixels on the upper and lower sides of the shaded lines). natural number) th value and the plurality of lines that the light-shielding upper and lower portion of the V-OB Calculating an approximate dark signal the ratio of the minimum value of the signal output from the pixels of the H-OB N (N is a natural number) and the reference value of the second value over the reference value of the dark current of the first means for the storage And
The output of the solid-state imaging device a difference signal between the first signal extended high levels of approximation dark current signal the calculated high extended signal of the video signal output from the effective pixels obtained by the obtaining unit An imaging method characterized by being used for a video signal . A solid-state imaging device, a first acquisition unit that acquires video signals output from effective pixels on the light-receiving surface of the solid-state imaging device, and signals output from light-shielded pixels above or below the light-receiving surface of the solid-state imaging device In a solid-state imaging device having a second acquisition unit to acquire,
First means for storing a signal output from the effective pixel acquired by the first acquisition unit at the time of light shielding and a signal output from the light-shielded pixel acquired by the second acquisition unit at the time of light shielding; The average value of values equal to or less than the Mth (M is a natural number) value from the maximum value of the signals output from the V-OB H-OB pixels on the upper and lower V-OB lines acquired by the second acquisition unit. H-OB of the upper and lower V-OBs of a plurality of light-shielded lines stored in the first acquisition unit and acquired by the second acquisition unit. The average value of the values equal to or less than the Mth (M is a natural number) value is calculated from the maximum value of the signal output from each pixel, and from the V-OB H-OB pixels at the upper and lower portions of the shaded lines. Average value of values less than M (M is a natural number) from the maximum value of the output signal The ratio of the maximum value of signals output from the H-OB pixels of V-OB at the upper and lower portions of the plurality of shielded lines to the reference value of the average value of the M or less (M is a natural number) value Calculating the approximate dark current signal over the dark current reference value of the first means for storing,
And means for calculating a difference signal between the first signal extended high levels of approximation dark current signal the calculated high extended signal of the video signal output from the effective pixels obtained by the obtaining unit , A signal obtained by expanding the high level of the calculated approximate dark current signal by the means for calculating the difference signal, and the height of the video signal output from the expanded signal and the effective pixel acquired by the first acquisition unit. A solid-state imaging device characterized by calculating a difference signal from a signal whose level is expanded and using the difference signal as an output video signal of the solid-state imaging device . A solid-state imaging device, a first acquisition unit that acquires video signals output from effective pixels on the light-receiving surface of the solid-state imaging device, and signals output from light-shielded pixels above or below the light-receiving surface of the solid-state imaging device In a solid-state imaging device having a second acquisition unit to acquire,
First means for storing a signal output from the effective pixel acquired by the first acquisition unit at the time of light shielding and a signal output from the light-shielded pixel acquired by the second acquisition unit at the time of light shielding; Means for calculating the Nth (N is a natural number) value from the minimum value of the signals output from the V-OB H-OB pixels of the upper and lower shaded lines acquired by the second acquisition unit; The dark current reference value is stored in the first storing means, and output from the V-OB H-OB pixels on the upper and lower sides of the plurality of light-shielded lines acquired by the second acquisition unit. The Nth (N is a natural number) value is calculated from the minimum value of the signal, and N (N is the minimum value of the signal output from the V-OB H-OB pixels on the upper and lower sides of the shaded lines). (Natural number) th value and V-OB of the upper and lower parts of the shaded lines The approximate dark current signal is calculated by multiplying the ratio of the minimum value of the signal output from the H-OB pixel to the reference value of the Nth (N is a natural number) value and the reference value of the dark current stored in the first means. And
Means for calculating a differential signal between a signal obtained by extending a high level of a video signal output from an effective pixel acquired by the first acquisition unit and a signal obtained by extending a high level of the calculated approximate dark current signal; , A signal obtained by expanding the high level of the calculated approximate dark current signal by the means for calculating the difference signal, and the height of the video signal output from the expanded signal and the effective pixel acquired by the first acquisition unit. A solid-state imaging device characterized by calculating a difference signal from a signal whose level is expanded and using the difference signal as an output video signal of the solid-state imaging device .