JPWO2018037674A1 - Image pickup apparatus, abnormal pixel detection interpolation method, and image pickup apparatus adjustment method - Google Patents

Abstract

The dark current of an imaging pixel (hereinafter referred to as a perfect black flaw) having an abnormally low sensitivity and a dark current and the dark current of a normal pixel are reliably identified and detected to interpolate the perfect black flaw. The image pickup apparatus has means for detecting dark current of a normal light-shielded pixel which approximately doubles at 6 ° C. to the image pickup element temperature, and makes the accumulation time inversely proportional to the detected dark current of the normal light-shielded pixel. The dark current of an imaging pixel (hereinafter referred to as a perfect black spot) with an abnormally low sensitivity in the imaging signal before light-blocked (OB) pixel signal correction, with 1 sec to 16384 sec dark light accumulation and dark current of a normal pixel. Is detected, and during normal imaging, perfect black spots are interpolated with the median of surrounding pixels.

Description

  The present invention relates to an imaging device such as a television camera, and more particularly to abnormal pixel detection and interpolation of an imaging device.

As a pixel defect detection method for a solid-state image sensor of a conventional television camera, image signals obtained by imaging a plurality of spectra obtained by dispersing imaging light at the same imaging position or a nearby imaging position for each spectral light are compared According to the result of the measurement, it is detected whether or not a pixel defect is generated in an image pickup element which has picked up any of the spectral light, and it is interpolated (see Patent Document 1).
See FIG. 11 of the overall configuration of a conventional imaging device. FIG. 11 shows a CMOS (Complementary Metal Oxide Semiconductor) image sensor integrated with AFE (Analog Front End) of noise reduction, gain correction and analog-digital conversion, and a light-shielded pixel signal (hereinafter referred to as OB) in video signal processing This is a conventional example in which correction is performed.

  However, since a random noise component is superimposed on each of a plurality of divided video signals on a video signal picked up by the image pickup element, a detection error is given to the pixel defect detection signal, and a pixel defect of a level smaller than random noise Detection was difficult. Therefore, the application is limited to a part of a long time exposure type camera etc. whose pixel defect signal is relatively larger than random noise (see Patent Document 2).

  Furthermore, in the imaging device, the dark current is generally doubled when the temperature rises by 6 ° C., and the dark current largely fluctuates in proportion to the exponential function of the imaging device temperature. Therefore, among the pixel defects, the dark current of the imaging pixel (hereinafter, referred to as a perfect black flaw) having a sensitivity that is abnormally low and the dark current is only a leakage current and the dark current of the normal pixel are reliably identified and detected. It is difficult. If the image pickup device temperature has a large amount of dark current, it is relatively easy to distinguish an image pickup pixel having a large amount of dark current among pixel defects (hereinafter referred to as a white blemish) from the dark current of a normal pixel.

JP 2002-44688 A JP, 2009-232200, A

  In the present invention, the dark current of an imaging pixel (hereinafter referred to as a perfect black scratch) having an abnormally low sensitivity and a dark current only as low as the leakage current, and an increase in temperature by 6 ° C. It is an object of the present invention to reliably identify and detect the dark current of a normal pixel which fluctuates largely in proportion to the function, and to interpolate a completely black flaw at the time of normal imaging.

The imaging device according to the present invention includes an imaging device (a color separation optical system and an imaging device with three or more imaging devices or an on-chip color filter with monochrome arrangement of R, G1, G2, B, or monochrome), and Means for independently interpolating using the signal level of surrounding pixels for each pixel of dark current larger than the first predetermined level of each red, green, and blue primary color video signal or (monochrome) luminance video signal, and video signal processing An imaging device having video signal processing means for correcting a light-shielded pixel signal (hereinafter referred to as OB) for subtracting a representative value of the light-shielded pixel video signal from the effective pixel video signal; Means that detects the dark current of normal pixels (means for calculating the Nth to N + Mth average values from the minimum value of OB pixels) or means for detecting the temperature of the imaging device (temperature Sensor, and the dark current of a normal pixel corresponding to the detected image sensor temperature (approximately doubled by 6 Means and dark current pixels smaller than the second predetermined level before OB correction of the video signal processing (imaging pixels whose sensitivity is abnormally low and the dark current is only a leak current degree (hereinafter, referred to as complete black flaws)) Means (detecting the dark current of a normal pixel) and means for interpolating using signal levels of surrounding pixels independently for each completely black scratched pixel of dark current smaller than the second predetermined level at the time of photographing And.
That is, the image sensor, means for detecting dark current at the time of light shielding for each pixel of the image signal of the image sensor, and signal levels of surrounding pixels independently for each pixel of dark current larger than the first predetermined level An image pickup apparatus comprising: means for interpolation; and video signal processing means for correcting a light-shielded pixel signal (hereinafter referred to as OB) for subtracting a representative value of the light-shielded pixel video signal from an effective pixel video signal in video signal processing;
Means for detecting dark current of normal pixels (means for calculating Nth to N + Mth average values from the minimum value of OB pixels) or means for detecting the temperature of the imaging device, corresponding to the detected imaging device temperature A means for making the accumulation time inversely proportional to the dark current of the normal pixel and performing light-shielded accumulation;
A means for identifying and detecting a dark current pixel smaller than a second predetermined level (hereinafter referred to as a perfect black flaw) from the dark current of the normal pixel before OB correction of the video signal processing;
And means for performing interpolation using signal levels of surrounding pixels independently for every completely black scratch pixel of dark current smaller than a second predetermined level at the time of photographing.

An imaging apparatus according to the present invention is the above-described imaging apparatus, which has approximately 15 times or more of the vertical scanning cycle (of the normal pixel corresponding to the detected imaging element temperature (approximately doubled by an increase of 6.degree. C.)). Vertical scan period with variable time of about 25 to 4096 seconds or about 60 times the vertical scanning period, with the storage time being inversely proportional to dark current, about 15 times to about 245760 times the vertical scanning period and about 60 Hz for the vertical scanning period A means for detecting a pixel defect (hereinafter referred to as a white defect) having an abnormally large dark current in a light-blocking accumulation time of about 60 Hz and a fixed time of about 1 second), and the detected image sensor temperature is about 2 at 6 ° C. Means of performing white defect interpolation before OB correction (in order to eliminate the influence of random noise) by making the accumulation time inversely proportional (approximately 1 second to 16384 seconds) to the dark current of the normal pixel to be doubled A means for detecting a pixel whose dark current is smaller than the second predetermined level after white blemish interpolation (imaged pixel having an extremely low sensitivity (hereinafter referred to as a complete black blemish)) And means for performing interpolation using signal levels of surrounding pixels independently for each complete black defect at the time of shooting, and means for performing OB correction after complete black defect interpolation.
That is, in the above-described imaging device,
The dark current of the normal pixel corresponding to the detected image sensor temperature based on the vertical scanning cycle makes the storage time inversely proportional to a predetermined variable time or vertical scanning cycle of the vertical scanning cycle within the range of any multiple of the vertical scanning cycle A means for detecting a pixel defect (hereinafter referred to as a white defect) having a dark current of a predetermined value or more in a predetermined light shielding accumulation time;
A means for performing the white defect interpolation before the OB correction by making the accumulation time inversely proportional to the dark current of the normal pixel corresponding to the detected image pickup device temperature and performing the shading correction before the OB correction;
A means for discriminating and detecting the completely black flaw from the dark current of the normal pixel after white flaw interpolation;
A means for performing interpolation using signal levels of surrounding pixels independently for each of the completely black flaws at the time of photographing;
And means for performing OB correction after perfect black-and-whites interpolation.
Furthermore, in the above-described imaging device, the white defect reference level at the accumulation of white defect detection or the white defect interpolation level at the time of standard imaging and the determination level are interchanged, and the image signal timing (address) determination and standard of white defects is performed. The white defect interpolation determination at the time of imaging is performed by the same means.
Further, in the above imaging apparatus, since perfect black scale interpolation is performed after white scale interpolation, (like peripheral pixel signals and image pickup signals of an image pickup signal or surrounding pixel signals of white scale interpolation signal and white scale interpolation signal) By changing the control signal of the white scratch video signal timing (address) at the time of determination below the white scratch level or the video signal timing (address) of a completely black scratch, the white scratch interpolation and the same circuit can be performed. It is characterized by having means for performing white defect interpolation and complete black defect interpolation with the same circuit by performing complete black defect interpolation and processing twice.

Further, according to the adjustment method of an image pickup device of the present invention, a color separation optical system and an image pickup element with on-chip color filter of Bayer arrangement of three or more image pickup elements or R, G1, G2, B, and each red of the image pickup element A means for detecting dark current at the time of light shielding for each pixel of the green and blue primary color video signals; a means for independently interpolating using signal levels of surrounding pixels for each pixel of dark current larger than the first predetermined level; An imaging apparatus comprising: video signal processing means for correcting a light shielding pixel signal (hereinafter referred to as OB) for subtracting a representative value of a light shielding pixel video signal from an effective pixel video signal in signal processing; (Heat run or high temperature aging, etc.) When the imaging device temperature is 40 ° C. or more, dark current is accumulated for about 1 to 16 seconds, and dark current smaller than the second predetermined level before OB correction of video signal processing Detects pixels (imaged pixels whose sensitivity is low and dark current is leak current only) (identified as dark current of the normal pixel) (detected as dark current of normal pixel), The interpolation is performed independently using signal levels of surrounding pixels.
That is, according to the adjustment method of the image pickup apparatus of the present invention, a color separation optical system and an image pickup element with three or more image pickup elements or a color filter with Bayer arrangement of R, G1, G2 and B, and red, green and blue of each of the image pickup elements A means for detecting dark current at the time of light shielding for each pixel of the primary color video signal, a means for independently interpolating using the signal level of surrounding pixels for each pixel of dark current larger than the first predetermined level, and video signal processing And an image signal processing unit for correcting a light-shielded pixel signal (hereinafter referred to as "OB") for subtracting the representative value of the light-shielded pixel video signal from the video signal of the effective pixel.
When the image pickup device temperature is a predetermined temperature or more, the image pickup device is light-shielded and accumulated in a predetermined time range,
Before OB correction of video signal processing, a pixel having a dark current smaller than a second predetermined level (hereinafter, referred to as a completely black flaw) is identified and detected as a dark current of a normal pixel,
At the time of photographing, interpolation is performed using signal levels of surrounding pixels independently for each pixel of the completely black flaw.

According to the present invention, it is possible to automatically detect an imaging pixel (hereinafter, referred to as a complete black flaw) signal whose sensitivity is low and dark current is only a leakage current, and interpolation using surrounding pixels of complete black flaw is possible. Become.
In addition, since the light-shielded pixel signal (hereinafter referred to as OB) correction is performed in the video signal processing after the perfect black scratch interpolation after white scratch interpolation, the OB correction operates stably without being affected by the white scratch and the perfect black scratch. The black of the video signal is stabilized, and the wide dynamic range of the television camera can be easily made.

FIG. 8 is a block diagram showing an embodiment of the entire configuration of the imaging device of the present invention (a shaded pixel signal (a CMOS imaging device in which AFEs are integrated) which subtracts a representative value of a shaded pixel video signal from an effective pixel video signal , OB) correction)), and is a color imaging apparatus using three-plate imaging elements of R, G, and B). FIG. 6 is a block diagram showing another embodiment of the entire configuration of the imaging device of the present invention, which is a color imaging device using 4-plate imaging elements of R, G1, G2 and B. FIG. 6 is a block diagram showing another embodiment of the entire configuration of the imaging device of the present invention, which is a color imaging device using an imaging element with an on-chip color filter of Bayer arrangement of R, G1, G2 and B. FIG. 6 is a block diagram showing another embodiment of the entire configuration of the imaging device of the present invention, which is a monochrome imaging device using a monochrome imaging element. An image at the time of light shielding of an imaging pixel with abnormally high dark current (hereinafter referred to as white defect), a normal pixel, and an imaging pixel with low sensitivity and low dark current (hereinafter referred to as complete black defect) The representative value of the video signal of the OB pixel is subtracted from the effective pixel video signal in the signal processing from the start of the imaging device of the completely black flaw video signal in the imaging signal (horizontal scanning line) before OB correction to saturation of internal temperature rise It is a schematic diagram which shows a change. (A) It is a schematic diagram which shows the change from the start of the imaging device of the complete black flaw video signal in the imaging signal (horizontal scanning line) before OB correction | amendment at the time of light shielding to saturation of internal temperature rise. (B) It is a schematic diagram which shows the change to the saturation of internal temperature rise from the imaging device start of the image signal of the white flaw of the temperature of an image pick-up element, accumulation time, and a dark current. White flaws of the temperature, accumulation time, and dark current of the image sensor of the image pickup signal before correction of the light shielding pixel signal (hereinafter referred to as OB) correction that subtracts the representative value of the light shielding pixel video signal at the time of light shielding from the effective pixel video signal 8 is a schematic view showing a change from the start of the image pickup apparatus of the video signal of completely black spots to saturation of the rise in internal temperature and output saturation by accumulation time of vertical scanning cycle unit of 14 bit output of the image pickup element. The ratio of dark current in inverse proportion to the ratio of the ratio of dark current to the ratio of temperature and storage time of the image pickup device before OB correction and the temperature of the image pickup device at 6 ° C. And a blackout accumulation time for detecting complete black spots. It is a detailed block diagram of the white flaw detection of one Example of this invention, and interpolation. FIG. 6 is a detailed block diagram of complete black blemish detection and interpolation according to an embodiment of the present invention. It is a schematic diagram for demonstrating one Example of this invention. It is a detailed block diagram which calculates the median of eight pixels around white blemish of one example of the present invention, and interpolates a white blemish. It is a detailed block diagram which calculates the median of eight pixels of the circumference of a perfect black crack of one example of the present invention, and interpolates a perfect black crack. It is a flowchart of white flaw detection and complete black flaw detection according to an embodiment of the present invention. It is a flowchart of white scratch interpolation and complete black scratch interpolation according to an embodiment of the present invention. It is a whole block diagram of the conventional imaging device (OB correction | amendment is carried out by video signal processing of the AFE integrated CMOS imaging element). N (4) th to N (4) + M (3) th average detection units from the minimum value of the OB pixel signal which is an example of a representative value detection unit of an OB pixel signal according to an example of the OB correction according to an embodiment of the present invention The dark current calculation OB correction of and the OB correction. N (2) -th to N (2) + M (1) -th average detection unit from the minimum value of the OB pixel signal as an example of the representative value detection unit of the OB pixel signal according to one example of the OB correction of the embodiment of the present invention The dark current calculation OB correction of and the OB correction. N (4) th to N (4) + M (3) th averages from the minimum value of the H-OB pixel signal as an example of the representative value detection unit of the OB pixel signal according to an example of the OB correction according to an embodiment of the present invention It is dark current calculation OB correction of a detection part and H-OB correction. N (4) th to N (4) + M (3) th average detection units from the minimum value of the OB pixel signal which is an example of a representative value detection unit of an OB pixel signal according to an example of the OB correction according to an embodiment of the present invention Dark current calculation OB correction of and V-OB correction.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIGS. 1A, 1B, 1C, and 1D are block diagrams showing an embodiment of the entire configuration of the imaging apparatus of the present invention, and are CMOS imaging elements in which AFE of noise reduction, gain correction, and analog-digital conversion is integrated. Then, in the video signal processing, OB correction for subtracting the representative value of the video signal of the light-shielded pixel from the effective pixel video signal is performed.
The television camera 30 of FIG. 1A is a color image pickup apparatus using a three-plate image pickup device of R, G, and B in video signal processing of a post-gamma matrix.
FIG. 1B is a block diagram showing another embodiment of the entire configuration of the imaging apparatus of the present invention, which is a color imaging apparatus using four-plate imaging elements of R, G1, G2, and B. In FIG.
FIG. 1C is a block diagram showing another embodiment of the entire configuration of the imaging apparatus of the present invention, which is a color imaging apparatus using an imaging element with an on-chip color filter in Bayer arrangement of R, G1, G2 and B.
FIG. 1D is a block diagram showing another embodiment of the entire configuration of the imaging apparatus of the present invention, which is a monochrome imaging apparatus using a monochrome imaging device.
The present invention does not limit the imaging device to CMOS, and may be a CCD (Charge Coupled Device) or the like.

  In FIGS. 1A and 1B, incident light from an object is imaged by the lens unit 31, and is separated into red light, green light and blue light by the prism unit 32, and each of the CMOS imaging device units 33R, 33G, 33G1, 33G2, Photoelectric conversion is performed at 33B. The photoelectrically converted R / G / B signals are subjected to noise reduction, gain correction, and analog-to-digital conversion in the CMOS image sensor, and sent to 35 of the video signal processing unit with white flaws completely black flaw detection correction function. Various video signal processing such as color correction, contour correction, gamma correction and knee correction are performed.

In FIGS. 1A, 1B, 1C, and 1D, the temperature sensor 20 is provided in the vicinity of the CMOS image sensor unit 33R, 33G, 33G1, 33G2, 33B, 58, 59 to detect temperature.
The image sensor control 54 controls accumulation (exposure) and readout of the CMOS image sensor units 33R, 33G, 33G1, 33G2, 33B, 58, 59 in accordance with an instruction of a CPU (Central Processing Unit) 39.
The lens unit 31 controls light shielding or standard imaging with an optical aperture or variable optical attenuation (hereinafter referred to as aperture) according to an instruction of the CPU 39.
Further, 50 is white defect detection interpolation, 51 is complete black defect detection interpolation, 52 is dark current calculation OB correction, and 53 is gamma color contour correction.
In FIGS. 1B and 1C, reference numeral 57 denotes a parallel-serial conversion unit (P / S), and the parallel-serial conversion unit (P / S) 57 generates a G imaging signal from the G1 and G2 imaging signals. Be done.
In FIG. 1D, 59 is a monochrome imaging device, 60 is gamma contour correction, and only monochrome luminance (Y) signal is output.

After various video signal processing and the like are performed in the digital signal processing unit 5,
Y = 0.2126 R + 0.7152 G + 0.0722 B Pb = 0.5389 (B−Y) Pr = 0.6350 (R−Y) From the R / G / B to the luminance signal (Y) and the color difference signal (Pb) Convert to / Pr). Then, it is converted into a serial video signal by the parallel-serial converter (P / S) 37 and output to the outside.

The CPU 39 controls each part of the television camera 30. In addition, the image display unit 40 of the viewfinder or monitor display has a menu for setting the imaging device or an imaging pixel having an abnormally large amount of dark current (hereinafter referred to as a white defect), a normal pixel, and an abnormally low sensitivity. The automatic interpolation operation with an imaging pixel having only a certain degree (hereinafter, referred to as a complete black flaw) or the interpolation operation with an arbitrary surrounding pixel manually is displayed.
In the viewfinder or monitor display 40, the menu screen is superimposed on the image of the subject, and the user looks at the menu screen while automatically detecting white flaws and completely black flaws Interpolation operation and interpolation at arbitrary pixels manually at surrounding pixels Display the operation.

Embodiment 1 Outline of Detection and Interpolation Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1A, 1B, 1C, 1D, 2, 3A, and 3B.
Here, FIG. 2 shows a video signal at the time of light shielding of an imaging pixel (hereinafter referred to as a perfect black defect) in which the dark current is abnormally high and the white pixel and the normal pixel have an abnormally low sensitivity. Change from the time the image pickup device starts up of the complete black scratch image signal to the saturation of the internal temperature rise in the imaging signal (horizontal scanning line) before OB correction that subtracts the representative value of the video signal of OB pixel from the effective pixel video signal (A) is an imaging device for an imaging pixel (hereinafter, referred to as complete black flaw) image signal having an abnormally low sensitivity in an imaging signal (horizontal scanning line) before OB correction at the time of light shielding. (B) is a schematic diagram showing a change from the start of the image to the saturation of the internal temperature rise, and (b) shows the temperature rise of the image signal of the image sensor temperature, the storage time and the dark current It is a schematic diagram which shows the change to saturation.
In general, in the imaging device, the dark current is approximately doubled when the temperature rises by 6 ° C. In cameras that devise heat dissipation, the internal temperature rise generally saturates in about 2 hours and reaches about 12 ° C. Therefore, even if the ambient temperature is constant, the internal temperature rise is 12 ° C., and the internal temperature rise is quadrupled at the time of saturation of the internal temperature rise as compared with the start time. Usually it is in the middle.

  FIG. 3A shows the temperature, the accumulation time, and the dark current of the image pickup element of the image pickup signal before the light shielding pixel signal (hereinafter referred to as OB) correction that subtracts the representative value of the light shielding pixel video signal at the light shielding time from the effective pixel video signal. It is a schematic diagram showing the output saturation by the accumulation time of the vertical scanning cycle unit unit of the change from the image pickup device startup of the white scratch and normal pixel and the complete black scratch image signal to saturation of internal temperature rise and 14 bit output of the image sensor. is there. The vertical scanning period is generally about 60 Hz or 50 Hz. There are also high speeds such as about 120 Hz, 150 Hz, about 180 Hz and about 240 Hz, and low speeds such as about 24 Hz and about 30 Hz. Hereinafter, the vertical scanning cycle is about 60 Hz, and the relationship between the vertical scanning cycle and the accumulation time will be described.

FIG. 3B is a schematic view showing the ratio of the ratio of the temperature and storage time of the image pickup device before the OB correction at the time of light shielding to the storage time and the ratio of dark current, and the temperature of the image pickup device and the blackout detection time.
The accumulation time of white flaw detection is a medium time (about 60 seconds of vertical scanning cycle 60 times that of the vertical scanning cycle) to detect a complete black flaw having only a dark current equivalent to the leakage current. The dark current of the normal pixel can be obtained by making the temperature of the image pickup element temperature inversely proportional to the dark current of the normal pixel twice at 6 ° C. and setting the accumulation time for complete black flaw detection to a long time (1 second to 163894 seconds), Certainly distinguish it from the dark current of completely black blemish that has only dark current equivalent to leakage current.

Unlike white blemish detection, since full black blemish signal detection is difficult, long-time accumulation at the time of detection is allowed.
Specifically, the detection limit immediately before shooting is a practical limit at a low temperature of about 128 seconds at an imaging device temperature of 22 ° C, but if it is a heat run after assembly adjustment of the imaging device or high temperature aging, etc. If the image pickup device temperature is 57 ° C. and the internal temperature rise is about 12 ° C., the light shielding accumulation time for complete black flaw detection is about 2 seconds.
Cameras not designed for heat dissipation at the maximum use temperature of 45 ° C have an internal temperature rise of about 19 ° C and the image pickup device temperature is 64 ° C, and the dark storage detection time of complete black flaw detection is about 1 of 60 times of about 60 Hz of the vertical scanning cycle It will be seconds.
The camera that devises heat dissipation particularly at the maximum use temperature of 40 ° C. has an internal temperature rise of about 8 ° C., and the image pickup device temperature becomes 48 ° C. There is almost no increase in cost if the dark storage time of complete black flaw detection in heat run or high temperature aging is about 1 second to about 16 seconds.

1A, 1B, 1C, 1D and 33R, 33G, 33G 1, 33G 2, 33B or 58 or 59 in the vicinity of a CMOS imaging device of the block diagram showing one embodiment of the entire configuration of the imaging device of the present invention; A temperature sensor 20 may be provided to detect the temperature of the CMOS image sensor, and the light blocking accumulation time of complete black mark detection may be inversely proportional to the temperature of the image sensor at 6 ° C. and twice the dark current of a normal pixel. Dark Current Calculation The representative value of the dark current of the normal pixel shielded by the OB correction 52 may be calculated.
In order to reliably distinguish between the dark current of a normal pixel and the dark current of a completely black flaw at low temperature when the dark current of the normal pixel is small, the light blocking accumulation time of the completely black flaw detection is 6 ° C. at the temperature of the image pickup element A method of calculating the representative value of the dark current of the normal pixel shielded by the dark current calculation OB correction 52 in order to make the dark current of the double normal pixel exactly in inverse proportion will be described in a third embodiment described later.

As described above, according to the present invention, a color separation optical system and an imaging element with three or more imaging elements or an on-chip color filter with a Bayer arrangement of R, G1, G2 and B, or a monochrome imaging element, and each red of the imaging element Means for detecting dark current at the time of light blocking for each pixel of the primary color video signal of green and blue or luminance video signal (monochrome), and signal levels of surrounding pixels independently for each pixel of dark current larger than the first predetermined level An image pickup apparatus comprising: means for interpolation using; and video signal processing means for correcting a light-shielded pixel signal (hereinafter referred to as OB) for subtracting a representative value of a light-shielded pixel video signal from an effective pixel video signal in video signal processing.
When the imaging device temperature is 40 ° C or higher after assembling and adjusting the imaging device (heat run or high temperature aging, etc.), approximately 1 to 60 seconds of about 60 Hz of the vertical scanning cycle (preferably ambient temperature 40 ° C or higher) Temperature rise 11 ° C or more, image pickup device temperature 51 ° C or more and approximately 4 seconds) The dark current pixel smaller than the second predetermined level by shading out and storing before OB correction of the video signal processing or stopping OB correction (The imaging pixel whose sensitivity is abnormally low and the dark current is only a leakage current (hereinafter referred to as a complete black flaw)) is detected (identified as the dark current of a normal pixel), and at the time of shooting The adjustment method of the image pickup apparatus is characterized in that interpolation is performed using signal levels of surrounding pixels independently for each small black current completely dark scratch pixel.

  In the above imaging apparatus, means for detecting dark current of a normal pixel corresponding to the temperature of the imaging element (approximately doubling at 6 ° C. increase) (N to N + Mth average values are calculated from the minimum value of OB pixels Means) or means (temperature sensor) for detecting the temperature of the imaging device, and inversely proportional to the dark current of a normal pixel corresponding to the detected imaging device temperature (approximately doubled at 6.degree. C.) for a long time (1 second And storing the readout and reading out the dark current smaller than the second predetermined level (identifying an imaging pixel whose sensitivity is abnormally low (hereinafter referred to as a complete black defect)) as the dark current of a normal pixel And an imaging device characterized in that it comprises means for detecting and means for interpolating independently using signal levels of surrounding pixels for each completely black flawed pixel at the time of photographing. (Specific measures will be described in the third embodiment.)

Second Embodiment Details of Detection and Interpolation Another embodiment of the present invention will be described below with reference to FIGS. 1A, 1 B, 1 C, and 4 to 10.
FIG. 4 is a detailed block diagram of white defect detection and interpolation according to an embodiment of the present invention.
FIG. 5 is a detailed block diagram of complete black blemish detection and interpolation according to an embodiment of the present invention.

FIG. 6 is a schematic view for explaining an embodiment of the present invention.
FIG. 6A is an embodiment of the present invention, and is a schematic diagram in which a complete black defect before OB correction at the time of light shielding is interpolated with the median of eight pixels around (a normal pixel around a complete black defect in a standard imaging signal Interpolation).
FIG. 6B is an embodiment of the present invention, a schematic diagram in which a perfect black defect before OB correction at the time of light shielding is interpolated by the median of eight pixels around (a surrounding black defect of a perfect black defect in a standard imaging signal Interpolation at normal pixels including
FIG. 6C is an embodiment of the present invention, and is a schematic diagram in which white defects in an image pickup signal before OB correction at the time of light shielding are interpolated with a median of 8 pixels around (white defects in a standard image pickup signal Interpolation at normal pixels).
FIG. 6D is an embodiment of the present invention, and is a schematic diagram in which white flaws in an image pickup signal before OB correction at the time of light shielding are interpolated with the median of eight surrounding pixels (around white flaws in a standard image pickup signal Interpolation at a normal pixel including white flaws).

FIG. 7 is a detailed block diagram of calculating medians of eight pixels around white defects and interpolating white defects according to an embodiment of the present invention.
FIG. 8 is a detailed block diagram for calculating the median of eight pixels around a complete black defect according to an embodiment of the present invention and interpolating the complete black defect.
FIG. 9 is a flowchart of white flaw detection and complete black flaw detection according to one embodiment of the present invention, and FIG. 10 is a flowchart of white flaw interpolation and complete black flaw interpolation according to one embodiment of the invention.

FIG. 4 is a detailed configuration diagram of imaging pixels (so-called white flaws) detection and interpolation with abnormally high dark current according to an embodiment of the present invention, and FIG. 5 is abnormally low in sensitivity with an embodiment according to the present invention. Is a detailed configuration diagram of an imaging pixel (hereinafter, referred to as a complete black flaw) detection having only a leakage current level.
In FIG. 4 and FIG. 5, the complete black defect reference level in the long time accumulation of complete black defect detection is subtracted from the white defect interpolation signal of R, the white defect interpolation signal of G, and the white defect interpolation signal of B to complete black defect Video signal timing (address) is determined, and during standard imaging, complete black flaw interpolation level determination during standard imaging is not performed, and interpolation at completely black flaw peripheral pixels is performed with complete black flaw video signal timing (address) Do.

  In FIGS. 4 and 5, reference numerals 12, 13 and 14 denote subtractors, 10 denotes a white defect detection and interpolation unit, 11 denotes a black defect detection and interpolation unit, and 15 denotes a video signal timing of the white defect (address And white defect interpolation determination at the time of standard imaging, 16 is interpolation at surrounding pixels of white defects, 17 is video signal timing (address) determination of black defects, and 18 is interpolation at surrounding pixels of black defects.

  In FIGS. 1A, 1B, 1C, 4 and 5 of the block diagram showing one embodiment of the entire configuration of the imaging apparatus of the present invention, the CPU 39 closes the diaphragm on the lens 31 to set the CMOS imaging device 33R, 33G, Give instructions to block 33B. Next, the CPU 39 instructs the light-shielded image pickup device control 54 to accumulate about 1 second of the medium time, and the image pickup device control 54 generates a medium time intermittent pulse for white flaw detection and supplies it to the CMOS image pickup devices 33R, 33G, 33B. . Then, based on the 12, 13, 14 subtractor difference between the R, G, B image pickup signals accumulated during light shielding time and the white defect reference level in the medium time accumulation of white defect detection, 15 is the video signal timing of the white defect (Address) Make a decision.

  1A, 1B, 1C, 4 and 5, next, the CPU 39 instructs the image sensor control 54 to store for a long time (1 to 163894 seconds) in inverse proportion to the dark current of the normal pixel, The element control 54 generates a long-term intermittent pulse for complete black mark detection and supplies it to the CMOS image sensors 33R, 33G, and 33B. Then, the R, G, B interpolation signals obtained by interpolating the R, G, B imaging signals accumulated for a long time in the dark pixels around the white flaws at 16 based on the video signal timing (address) of the white flaws The image signal timing (address) judgment of the complete black defect is made on the basis of the subtractor difference of 12, 13, 14 with the complete black defect reference level in the long-term accumulation of the black defect detection.

  At the time of standard imaging, the CPU 39 causes the lens 31 to open the diaphragm, instructs the light-shielded imaging element control 54 to perform standard imaging, and the imaging element control 54 generates a standard imaging pulse and supplies it to the CMOS imaging elements 33R, 33G, 33B. . The image signal timing (address) judgment of a white defect is performed on the basis of the subtractor difference of 12, 13 and 14 between R, G and B image pickup signals picked up in the standard image pickup and the white defect interpolation level at the standard image pickup. 16 is an image pickup signal equal to or less than the white defect interpolation level, and performs interpolation in the surrounding pixels of the white defect at the video signal timing (address) of the white defect. The interpolation signal of R, G, B which performed the interpolation in the surrounding pixel of the white defect in 16 performs interpolation with the central value of the surrounding pixel in the complete black defect based on the video signal timing (address) of the completely black defect. . The complete black defect interpolation level determination at the time of standard imaging is not performed.

  In addition, in FIG. 4, the middle time of the white defect detection (approximately 15 times or more of the vertical scanning cycle (of which corresponding to the detected image pickup device temperature (approx. Inverse time, approximately 15 times to approximately 245760 times the vertical scanning period and approximately 60 Hz for the vertical scanning period, or approximately 60 times as vertical scanning period at approximately 60 times the variable time of 0.25 seconds to 4096 seconds or approximately 60 Hz for the vertical scanning period The white defect reference level for 1 sec fixed time) and the white defect interpolation level at standard imaging or the white defect interpolation level at standard imaging are replaced with the determination level to determine the video signal timing (address) of white defects and white at standard imaging The defect interpolation determination can be performed by the same means, and the circuit can be downsized and the cost can be reduced.

  FIG. 6A is an embodiment of the present invention, and is a schematic diagram in which a complete black defect before OB correction at the time of light shielding is interpolated with the median of eight pixels around (a normal pixel around a complete black defect in a standard imaging signal Interpolation), and the center completely black scratch image pickup signal 0 is interpolated with the median 64 or 80 of the surrounding ambient normal pixel image pickup signals 32, 48, 56, 64, 80, 96, 102, 128.

  FIG. 6B is an embodiment of the present invention, a schematic diagram in which a perfect black defect before OB correction at the time of light shielding is interpolated by the median of eight pixels around (a surrounding black defect of a perfect black defect in a standard imaging signal Interpolation at normal pixels), and the center completely black scratched image pickup signal 0 is a surrounding surrounding normal pixel pickup signal 32, 48, 56, 64, 80, 102, excluding the completely black scratched image pickup signal 0 at the periphery. It is interpolated at a median 64 of 128.

  FIG. 6C is an embodiment of the present invention, and is a schematic diagram in which white defects in an image pickup signal before OB correction at the time of light shielding are interpolated with a median of 8 pixels around (white defects in a standard image pickup signal Interpolation at normal pixels), and the center white scratch image pickup signal 1024 is interpolated at the median 64 or 80 of the surrounding ambient normal pixel pickup signals 32, 48, 56, 64, 80, 96, 102, 128 .

FIG. 6D is an embodiment of the present invention, and is a schematic diagram in which white flaws in an image pickup signal before OB correction at the time of light shielding are interpolated with the median of eight surrounding pixels (around white flaws in a standard image pickup signal Interpolation at a normal pixel including white spots), and the white spot imaging signal 1024 at the center is interpolated at the median 80 of the surrounding normal pixel imaging signals 32, 48, 56, 80, 96, 102, 128 .
Here, complete black defect interpolation is performed after white defect interpolation.

FIG. 7 and FIG. 8 are detailed configuration diagrams for calculating and interpolating the median value of eight surrounding pixels according to an embodiment of the present invention.
In FIG. 7 and FIG. 8, 9 is a surrounding pixel signal selection part, 16 is an interpolation in the surrounding pixel of a white defect, 18 is an interpolation in a surrounding pixel of a black defect, 19 is a surrounding pixel center value detecting part, 21, Reference numerals 22, 23, 24, 25, 26, 27 and 28 denote comparison units, and 29 denotes a video signal switch.

In the surrounding pixel signal selection unit 9 of FIGS. 7 and 8, 5 and 6 are line memories, 7 is a video signal switch, and 8 is a delay unit. The line memories 5 and 6 generate 1H and 2H imaging signals from the imaging signal of 0H, and generate 1H2H white defect interpolation signals from the 0H white defect interpolation signal.
The video signal switching device 7 selects an imaging signal of 0H, 1H, 2H to generate a surrounding pixel signal of the imaging signal, selects a white defect interpolation signal of 0H, 1H, 2H, and a surrounding pixel of a white defect interpolation signal Generate a signal. A frame memory (not shown) may be used instead of the line memories 5 and 6.

  In FIG. 7 and FIG. 8, the delay unit 8 delays the imaging signal of the surrounding pixel center value detection unit 19 by the delay and delays the white defect interpolation signal. Then, the peripheral pixel central value detection unit 19 detects the peripheral pixel central value of the imaging signal or the white defect interpolation signal in the comparison units 21 to 28 from the peripheral pixel signal of the imaging signal, and the peripheral pixel signal of the white defect interpolation signal The peripheral pixel central value of the white defect interpolation signal is detected by the comparison units 21 to 28.

  Then, the white scratch image signal timing (address) of FIG. 4 and the white scratch level below the white scratch level from the white scratch interpolation determination 15 at standard imaging and the white scratch image signal timing (address) determination in FIG. The image pickup signal is interpolated to the peripheral pixel center value of the image pickup signal by the switch 29 of the interpolation unit in the peripheral pixel. In addition, according to the video signal timing (address) of the completely black flaw from the video signal timing (address) judgment 17 of the black flaw in FIG. The signal is interpolated to the center pixel center value of the white defect interpolation signal.

In FIG. 7 and FIG. 8, even if there are a plurality of white flaws in surrounding pixels, complete black flaw interpolation is performed after white flaw interpolation, so complete black flaw interpolation is not affected by white flaws.
Further, in FIGS. 7 and 8, since perfect black scale interpolation is performed after white scale interpolation, input (like peripheral pixel signal and image pickup signal of imaging signal or surrounding pixel signal of white scale interpolation signal and white scale interpolation signal) White flaws in the same circuit by changing the signal and changing the control signal of the white scratch video signal timing (address) or white black scratch video signal timing (address) when the white scratch level is determined or less By performing the interpolation and the complete black defect interpolation twice, it is possible to perform the white defect interpolation and the complete black defect interpolation in the same circuit, and it is possible to realize the miniaturization and the cost reduction of the circuit.

  FIG. 9 is a flowchart of white blemish detection according to an embodiment of the present invention and detection of an imaging pixel (hereinafter, referred to as a perfect black blemish) in which the sensitivity is abnormally low and the dark current is only a leakage current. 3 is a flowchart of white defect interpolation of one embodiment and interpolation of an imaging pixel (hereinafter, referred to as complete black defect) in which the sensitivity is abnormally low and the dark current is only a leakage current level.

  In FIG. 9, the CPU 39 performs approximately 1 second of light shading accumulation and readout after the start of detection of white blemish detection and detection of an imaging pixel (hereinafter referred to as complete black blemish) in which the sensitivity is abnormally low and the dark current is only a leakage current. It is judged whether the video signal of the pixel exceeds the white defect level (S902), and if "NO", the process proceeds to (S904), and if "YES", the video timing (address) of the white defect is stored (S903) Then, the process proceeds to (S904).

Next, the CPU 39 performs light shielding accumulation for a long time (from 1 second to 163894 seconds) in inverse proportion to the dark current of a doubled normal pixel at a temperature rise of 6 ° C. of the image pickup element and performs readout (S904) Whether the video timing (address) of the white defect is determined (S905), it is determined if "NO" (S908), and if "YES", the median of surrounding 8 pixels is calculated (S906), and the median of surrounding 8 pixels is used. After interpolation (S907), the process proceeds to (S908).
Next, the CPU 39 determines whether the video signal of the pixel is lower than the black defect level (S908), and proceeds to the end if "NO", stores the video timing (address) of the black defect if "YES" (S909) , Go to the end.
This is the end of the process of detecting white flaws and completely black flaws.

In FIG. 10, the CPU 39 reads out by standard imaging after interpolation of white defect interpolation and an imaging pixel (hereinafter, referred to as complete black defect) in which the sensitivity is abnormally low and the dark current is only a leakage current (S1001) Whether the video signal of the pixel is below the white defect interpolation level is determined (S1002), if "NO", the process proceeds to (S1006), and if "YES", it is determined whether the video timing (address) of the white defect is (S1003) If "NO", the process proceeds to (S1006), and if "YES", the median of the surrounding eight pixels is calculated (S1004), and the median of the surrounding eight pixels is interpolated (S1005), and the process proceeds to (S1006).
Next, the CPU 39 determines whether the video signal of the pixel is the video timing (address) of the black defect (S1006), and proceeds to the end if "NO", and calculates the median of the surrounding 8 pixels if "YES" (S1007) Then, interpolation is performed with the median value of the surrounding eight pixels (S1008), and the process proceeds to end.
Above, interpolation of detection of a white flaw and a complete black flaw ends.

  That is, in the image pickup apparatus according to the first embodiment, the accumulation time is inversely proportional to the dark current of a normal pixel which is about 15 times or more of the vertical scanning cycle (corresponding to the detected image sensor temperature (approx. If the vertical scanning period is about 60 times, the vertical scanning period is about 60 times that of the vertical scanning period when the vertical scanning period is about 60 Hz, or if the vertical scanning period is about 60 Hz when the vertical scanning period is about 60 Hz A means for detecting a pixel defect (hereinafter referred to as a white blemish) in which dark current is abnormally high at light-blocking accumulation time in the middle of time), and normal pixels (the image sensor temperature increases approximately Means for detecting the dark current (mean for calculating the N + Mth average value from N from the minimum value of OB pixels) or means for detecting the temperature of the imaging element (temperature sensor), and the detected imaging element The accumulation time is inversely proportional (approximately 1 second to 16384 seconds) to the dark current of a normal pixel, which is approximately doubled at a 6 ° C. rise (before removing the influence of random noise) before OB correction A means for performing white defect interpolation (or stopping OB correction), and a pixel of dark current smaller than a second predetermined level after white defect interpolation (image pickup pixel having an abnormally low sensitivity (hereinafter referred to as complete black defect) Means for detecting the dark current of a normal pixel), means for interpolating using signal levels of surrounding pixels independently for every completely black flaw during photographing, and means for performing OB correction after completely black scratch interpolation And an image pickup apparatus characterized by comprising:

  Further, in the above imaging apparatus, the white defect reference level at the accumulation of white defect detection or the white defect interpolation level at standard imaging and the determination level are interchanged, and the white defect video signal timing (address) determination and standard imaging are performed. Means for performing the white defect interpolation determination by the same means.

  Further, in the above imaging apparatus, since perfect black scale interpolation is performed after white scale interpolation, (like peripheral pixel signals and image pickup signals of an image pickup signal or surrounding pixel signals of white scale interpolation signal and white scale interpolation signal) By changing the control signal of the white scratch video signal timing (address) at the time of determination below the white scratch level or the video signal timing (address) of a completely black scratch, the white scratch interpolation and the same circuit can be performed. An imaging apparatus is characterized by including means for performing white defect interpolation and complete black defect interpolation in the same circuit by performing complete black defect interpolation and processing twice.

Example 3 FIG. 12A is an example of the OB correction 52 according to an example of the present invention, and shows N (4) th to Nth minimum values of the OB pixel signal in an example of the representative value detection unit of the OB pixel signal. 4) It comprises the + M (3) th average detection unit 48 and the subtractor 4;
FIG. 12B shows N (2) th to N (2) + M (1) th from the minimum value of the OB pixel signal as an example of the representative value detection unit of the OB pixel signal according to an example of the OB correction of the embodiment of the present invention. Dark current calculation OB correction of the average detection unit and the OB correction.

FIG. 12C shows N (4) th to N (4) + M (3) from the minimum value of the H-OB pixel signal as an example of the representative value detection unit of the OB pixel signal according to an example of the OB correction according to an embodiment of the present invention. Dark current calculation OB correction of the second average detection unit and the H-OB correction.
FIG. 12D shows N (4) th to N (4) + M (3) th from the minimum value of the OB pixel signal as an example of the representative value detector of the OB pixel signal according to an example of the OB correction according to the embodiment of the present invention. Dark current calculation OB correction of the average detection unit and the V-OB correction.

In the V-OB correction of FIGS. 12A to 12D, although the delay unit 55 is not essential, the effective pixel signal is delayed by the delay unit 55, and the correction becomes more stable at V-OB after the effective pixel.
If V-OB correction is also used for vertical streak correction and H Shading correction, a compact signal processing circuit can output a video signal with stable black, and it becomes easy to achieve wide dynamic range of a television camera.
12A to 12D, the N (4) th to N (4) + M (3) th average detection units 48 from the minimum value of the OB pixel signal are 21, 22, 23, 24, 25, 26, 27, A comparison unit with 28, an adder with 43, 44 and 45, and a 1⁄4 (2-bit shift) of 46, 47 is composed of the 4th to 4 + 3rd detection units from the minimum value.

  12A, 12C, and 12D, the N (4) th to N (4) + M (3) th average detection unit 47 from the minimum value of the OB pixel signal is for excluding white flaws and complete black flaws. White dots and perfection by detecting the N (4) th to the N (4) + M (3) th from the minimum value in the 8 comparators from the OB pixel signal and adding and shifting by 2 bits to 1/4. The OB pixel signal excluding black flaws is averaged.

  In FIG. 12B, the N (2) -th to N (2) + M (1) -th average detection unit 47 from the minimum value of the OB pixel signal removes eight from the OB pixel signal in order to exclude white flaws and completely black flaws. White flaws and completely black flaws were excluded by detecting N (2) th to N (2) + M (1) th from the minimum value in this comparison section, adding and shifting by 1 bit and halving Add and average OB pixel signals.

As the image pickup element of the television camera becomes as high as 2K, 4K, and 8K, the number of OB pixels decreases as compared with the effective pixels. Therefore, it becomes susceptible to the influence of the white flaws and the complete black flaws of the OB pixel.
However, in the present invention, the dark current of the normal pixel of the OB pixel signal that increases about twice when the temperature of the image pickup device rises by 6 ° C. is detected without being affected by the white flaws and the complete black flaws of the OB pixels. Can. As a result, it is possible to make the accumulation time inversely proportional to the dark current of the detected normal pixel (which approximately doubles at 6 ° C. with the image sensor temperature).
Also, if the dark current signal of the normal pixel of the detected OB pixel signal is subtracted from the imaging effective pixel signal, the OB correction can be stably performed by the video signal processing without being affected by the white flaw and the complete black flaw of the OB pixel. The black of the video signal is stabilized, and the wide dynamic range of the television camera is facilitated.

By detecting the representative value of the OB pixel signal that increases approximately twice when the temperature of the imaging device rises by 6 ° C., it is possible to detect the temperature of the imaging device without separately providing a temperature sensor.
By making the accumulation time inversely proportional to the dark current of a normal pixel that has been detected (the image sensor temperature increases by approximately 6 ° C.), the dark current of a normal pixel at low temperature with a small dark current of the normal pixel The dark current of an abnormally low sensitivity pixel (complete black flaw) having only a dark current equivalent to the current is reliably identified, and a complete black flaw is reliably detected.
Unlike white blemish detection, it is difficult to detect an imaging pixel (hereinafter referred to as complete black blemish) signal whose sensitivity is abnormally low and dark current is only about a leakage current, so long-term accumulation at detection at low temperature is allowed.

  That is, in the image pickup apparatus of the first embodiment, the accumulation time is reversed to the dark current of the normal pixel in which the fixed time of about 1 second (the fixed time of about 1 second or the detected image pickup device temperature rises about A means for detecting a pixel defect (hereinafter referred to as a white defect) having an abnormally large amount of dark current in a light-blocking accumulation time in proportion to about 0.25 seconds to 4096 seconds variable time) (image sensor temperature rises by 6 ° C. Means for detecting dark current of normal pixels (mean for calculating an average value from N to N + Mth from the minimum value of OB pixels) or means for detecting the temperature of the imaging device (temperature sensor); The accumulation time is reversely proportional to the dark current of a normal pixel in which the detected image pickup device temperature is approximately doubled at a rise of 6 ° C. (approximately 1 second to 16384 seconds), and the influence of random noise is removed ) Before OB correction (also A means for performing white defect interpolation by stopping OB correction, and a pixel of dark current smaller than the second predetermined level after white defect interpolation (image pickup pixel having an abnormally low sensitivity (hereinafter referred to as complete black defect)) (Detects the dark current of a normal pixel), interpolates using signal levels of surrounding pixels independently for every completely black flaw at the time of photographing, and performs OB correction after completely black flaw interpolation And an image pickup apparatus characterized by comprising:

  In the above-described imaging device, the combination of the second embodiment and the third embodiment is the normal time during which the image signal processing is performed during the middle time (fixed time of approximately 1 second or the detected imaging element temperature is approximately doubled by A means for performing white flaw detection in a light-blocking accumulation time (approximately 0.25 seconds to 4096 seconds variable time) with the accumulation time being inversely proportional to the dark current, and the white accumulation sensor temperature after the white flaw detection. Is inversely proportional and accumulated for about 4 seconds to 4096 seconds (with removing the influence of random noise) before OB correction or before OB correction to perform white defect interpolation, smaller than the second predetermined level Means for detecting pixels of dark current (image pickup pixels with extremely low sensitivity (hereinafter referred to as complete black blemishes) (identified as dark current of normal pixels) and surrounding pixels independently for every completely black blemish at the time of shooting Means to interpolate using the signal level of And an image pickup apparatus characterized in that

  The above description has been focused on a color camera using three R, G, and B imaging devices in FIG. 1A, but a color camera using four, R, G1, G2, and B four-plate type imaging devices in FIG. It does not matter as long as OB correction is performed by image signal processing, whether it is a color camera using an imaging element of the 1C on-chip color filter or a monochrome camera using an imaging element without the on-chip color filter in FIG.

In addition, the white defect reference level during medium time accumulation of white defect detection or the white defect interpolation level at the time of standard imaging and the determination level are interchanged, and the white scratch image signal timing (address) determination at white defects and the white defect interpolation at the standard imaging The determination can be performed by the same means, and the circuit can be miniaturized and the cost can be reduced.
Furthermore, change the input signal, change the video signal timing (address) of white flaws at the time of determination below the level of white flaws, or the video signal timing (address) of completely black flaws) It is possible to perform the round process and perform the white defect interpolation and the complete black defect interpolation by the same means, and it is possible to realize the miniaturization and the cost reduction of the circuit.

In FIG. 7 and FIG. 8, even if there are a plurality of white flaws in surrounding pixels, complete black flaw interpolation is performed after white flaw interpolation, so complete black flaw interpolation is not affected by white flaws.
In addition, since the light-shielded pixel signal (hereinafter referred to as OB) correction is performed in the video signal processing after the perfect black scratch interpolation after white scratch interpolation, the OB correction operates stably without being affected by the white scratch and the perfect black scratch. The black of the video signal is stabilized, and the wide dynamic range of the television camera can be easily made.
As the image pickup element of the television camera has high pixels such as 2K (1920H × 1080V), 4K (3840H × 2160V), and 8K (7680H × 4320V), the number of OB pixels is smaller than that of effective pixels. Therefore, it becomes easy to receive the influence of the white flaw of OB pixel. However, according to the present invention, it is possible to detect a representative value of the OB pixel signal, which increases about twice when the temperature of the image pickup device rises by 6 ° C., without being affected by white defects of the OB pixel.
Conventionally, unlike white blemish detection, automation of imaging pixel (hereinafter referred to as complete black blemish) signal detection and interpolation in which the sensitivity is abnormally low and dark current is only a leakage current is difficult, and manual interpolation has been performed.
According to the present invention, it is possible to automatically detect and interpolate completely black spots, and it is easy to increase the number of pixels and to read at high speed compared to a CCD image sensor, and for broadcasts which can not tolerate complete black flaws of an inexpensive MOS image sensor. Applications to cameras, surveillance cameras (such as nuclear power plants and Shinkansen), and industrial cameras (such as confirmation of automobile painting and textiles) that require high reliability are accelerated.

  The imaging device according to the embodiment of the present invention can automatically detect an imaging pixel signal whose sensitivity is abnormally low and the dark current is only a leakage current, and interpolation using surrounding pixels of completely black spots becomes possible.

  As mentioned above, although one embodiment of the present invention was described in detail, the present invention is not limited to the embodiment mentioned above, and can be variously changed and carried out in the range which does not deviate from the meaning of the present invention.

  A broadcast camera or high reliability that is used for detecting perfect black spots and interpolating with surrounding pixels to generate high-quality video signals by accumulating for a long time in inverse proportion to the accumulation (exposure) time to the image sensor temperature It can be applied to surveillance cameras (such as nuclear power stations and Shinkansen) and industrial cameras (for checking automobile body painting, textiles, etc.). This application claims the benefit of priority based on Japanese Patent Application No. 2016-164619 filed on August 25, 2016, the entire disclosure of which is incorporated herein by reference.

  4: Subtractor 5, 6: Line memory 7: 7: Video signal switching device 8: Delay device 9: Surrounding pixel signal selection unit 12, 13, 14: Subtractor 15: Video signal timing of white flaws ( Address) Judgment and white scratch interpolation judgment at standard imaging, 16: Interpolation in surrounding pixels of white flaw, 17: Video signal timing (address) judgment of complete black flaw, 18: Interpolation in surrounding pixel of complete black flaw, 19: ambient pixel median value detection unit, 20: temperature sensor, 21, 22, 23, 24, 25, 26, 27, 28: comparison unit, 29: video signal switcher, 30: television camera, 31: lens, 32: Prism, 33R, 33G, 33G1, 33G2, 33B: CMOS image pickup device, 34: White scratch interpolation, 35: White scratch complete black scratch detection Video signal processing unit with interpolation function, 36: MATRIX section, 37: Parallel- Real conversion unit (P / S) 38: white flaws completely black flaw detection interpolation part 39: CPU 40: view finder 41: video signal processing part with white flaw detection interpolation function 42: white flaw detection interpolation part 43, 44, 45: Adder, 46: 1/4 (2-bit shift), 47: From the minimum value to 4 to 4 + 3rd detection unit, 48: From the minimum value of the OB pixel signal to N (4) to N (4) + M (3) th average detection unit, 49: OB correction, 50: white flaw detection interpolation, 51: complete black flaw detection interpolation, 52: dark current calculation OB correction, 53: gamma color contour correction, 54: image sensor control , 55: delay unit, 56: 1/2 (1 bit shift), 57: parallel-serial conversion unit (P / S), 58: imaging device with on-chip color filter, 59: monochrome imaging device, 60: gamma contour correction , 61: line memory, 71: la Emissions averaging section.

Claims (3)

Interpolation using an image sensor, means for detecting dark current at the time of light shielding for each pixel of the image signal of the image sensor, and signal levels of surrounding pixels independently for each pixel of dark current larger than the first predetermined level And an image signal processing means for correcting a light-shielded pixel signal (hereinafter referred to as OB) for subtracting a representative value of the light-shielded pixel video signal from the effective pixel video signal in the video signal processing.
Means for detecting dark current of normal pixels (means for calculating Nth to N + Mth average values from the minimum value of OB pixels) or means for detecting the temperature of the imaging device, corresponding to the detected imaging device temperature A means for making the accumulation time inversely proportional to the dark current of the normal pixel and performing light-shielded accumulation;
A means for identifying and detecting a dark current pixel smaller than a second predetermined level (hereinafter referred to as a perfect black flaw) from the dark current of the normal pixel before OB correction of the video signal processing;
An imaging device characterized by comprising means for interpolating independently using signal levels of surrounding pixels independently for every completely black flaw pixel of dark current smaller than a second predetermined level at the time of photographing. In the imaging device of claim 1,
The dark current of the normal pixel corresponding to the detected image sensor temperature based on the vertical scanning cycle makes the storage time inversely proportional to a predetermined variable time or vertical scanning cycle of the vertical scanning cycle within the range of any multiple of the vertical scanning cycle A means for detecting a pixel defect (hereinafter referred to as a white defect) having a dark current of a predetermined value or more in a predetermined light shielding accumulation time;
A means for performing the white defect interpolation before the OB correction by making the accumulation time inversely proportional to the dark current of the normal pixel corresponding to the detected image pickup device temperature and performing the shading correction before the OB correction;
A means for discriminating and detecting the completely black flaw from the dark current of the normal pixel after white flaw interpolation;
A means for performing interpolation using signal levels of surrounding pixels independently for each of the completely black flaws at the time of photographing;
And a means for performing OB correction after perfect black scratch interpolation. Dark current at the time of light blocking for each pixel of the red, green, and blue primary color image signals of the color separation optical system, the three or more image sensors, or the color filter with R, G1, G2, B Bayer arrangement Means for detecting the dark current pixels, and means for interpolating independently using the signal levels of surrounding pixels for each pixel of dark current larger than the first predetermined level; And an image pickup apparatus having video signal processing means for correcting a light-shielded pixel signal (hereinafter referred to as OB) to be subtracted from the video signal.
When the image pickup device temperature is a predetermined temperature or more, the image pickup device is light-shielded and accumulated in a predetermined time range,
Before OB correction of video signal processing, a pixel having a dark current smaller than a second predetermined level (hereinafter, referred to as a completely black flaw) is identified and detected as a dark current of a normal pixel,
A method of adjusting an image pickup apparatus, wherein interpolation is performed using signal levels of surrounding pixels independently for each of the completely black flaw pixels at the time of photographing.

Images