JP2005142722A - Video signal processing apparatus and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve precision of excellent flaw correction by reducing omission of detection of a flaw of an imaging element and erroneous detection. <P>SOLUTION: In a video signal processing apparatus 1, an imaging control part 19 functioning as an imaging control means for flaw detection performs exposure control for varying the exposure quantity of the imaging element to an exposure quantity for flaw detection, and an imaging element generates a video signal for flaw detection under the control. A flaw detection part 15 detects the flaw of the imaging element by using the video signal for flaw detection and a flaw correction part 17 corrects the video signal of a subject according to the detected flaw. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a video signal processing apparatus for processing a video signal generated by an image sensor such as a CCD, and more particularly, a video signal for detecting a scratch (pixel defect) existing in the image sensor and correcting a video signal. The present invention relates to a processing apparatus.

  In general, an image sensor formed of a semiconductor such as a CCD may include a pixel unit defect, that is, a flaw, due to a local crystal defect of the semiconductor. When a subject is imaged by an image sensor having such a scratch, an appropriate video signal corresponding to the optical image of the subject cannot be obtained, and the image quality of the video signal deteriorates.

  There are white scratches and black scratches in the scratches of the image sensor. A white defect is a pixel defect in which a constant high bias voltage is always added regardless of the amount of light incident on the pixel. Therefore, the output (pixel value) of a pixel having white flaws is generally higher than the original proper level. The effect of white scratches appears as high brightness white spots on the video. On the other hand, a black flaw is a pixel defect of a pixel whose photoelectric sensitivity is extremely lower than that of a normal pixel. Therefore, the output (pixel value) from the pixel having black flaws is lower than the original proper level. The effect of black scratches appears as black dots with low brightness on the video.

  Conventionally, a defect correction process is performed in order to improve image quality deterioration due to the defect as described above. In this scratch correction process, first, a pixel having a scratch is detected, and then a video signal of the pixel having a scratch is corrected. In the process of detecting scratches, pixels that are extremely bright compared to adjacent pixels are detected as white scratches in the video signal obtained by the image sensor, and compared to adjacent pixels. Pixels with extremely low brightness are detected as black scratches. That is, it is determined that there is a scratch when the difference between the pixel values of adjacent pixels is larger than a predetermined threshold value. Then, the pixel values of the pixels detected as white scratches and black scratches are corrected so as to improve image quality degradation due to scratches.

  A conventional technique for improving image quality degradation due to scratches on an image sensor is disclosed in Patent Document 1, for example. Patent Document 1 describes a technique for improving the detection accuracy of white scratches.

Japanese Patent Laid-Open No. 7-7675 (paragraphs 0022-0025, FIG. 1)

  FIG. 13 is a diagram illustrating pixel values of a video signal generated by an image sensor having white flaws in a conventional video signal processing apparatus. In the example of FIG. 13, since there are white scratches in the high-luminance portion of the video signal, the difference in pixel value between the scratched pixel and the normal pixel adjacent thereto is small. As a result, it is not easy to determine the presence or absence of scratches based on the difference in pixel values between adjacent pixels. Similarly, FIG. 14 shows a video signal having black flaws. When there is a black flaw in the low luminance portion of the video signal, the difference in pixel value between the flawed pixel and the normal pixel adjacent thereto is small. As a result, scratch detection is not easy. In particular, when the video signal is gamma-corrected, the difference between the pixel values in the high luminance part and the low luminance part is further reduced. If the difference between the pixel values of the defective pixel and the normal pixel is small, a detection failure that the defective pixel is buried in the normal pixel and cannot be detected, or a false detection that detects the normal pixel as a defective pixel occurs. This makes it easier to detect scratches.

  In the technique described in Patent Literature 1, when a difference between adjacent pixels is evaluated to detect a white defect, a threshold value for determining a white defect is lowered in a high-luminance portion, and the difference between pixel values is The detection accuracy of white flaws in a relatively small high-luminance part is improved, and detection flaws in white flaws are reduced. However, even if the scratch detection threshold is lowered in the high-luminance part, the difference between the pixel value of the scratched pixel and the normal pixel remains the same, and detection omissions and false detections caused by the small difference remain unchanged. The potential still exists.

  The present invention has been made in order to solve the conventional problems, and is a technique for improving the image quality of a video signal of a subject obtained by an image sensor by reducing detection errors and false detections of flaws in the image sensor. The purpose is to provide.

  The video signal processing apparatus according to the present invention has a flaw detection imaging control for causing the image sensor to generate a flaw detection video signal under exposure control in which the exposure amount of the image sensor is set to a flaw detection exposure amount for flaw detection. A flaw detection means for detecting flaws in the image pickup device using the flaw detection video signal, and a subject image obtained by the image pickup device based on the flaws detected by the flaw detection means. And a defect correcting means for correcting the signal.

  With this configuration, a defect detection video signal is generated by the image sensor under exposure control in which the exposure amount of the image sensor is set to a defect detection exposure amount for defect detection. The flaw detection means can detect the presence or absence of flaws based on whether or not a normal pixel luminance value is obtained under a flaw detection exposure amount. Therefore, detection defects and erroneous detection of scratches are reduced, and the video signal of the subject can be satisfactorily corrected.

  The video signal processing apparatus of the present invention further includes flaw position information storage means for storing information on the position of the flaw detected by the flaw detection means, and the flaw correction means is stored in the flaw position information storage means. The image signal of the subject is corrected using the information on the position of the flaw.

  With this configuration, the position of the stored flaw is detected when the flaw of the image sensor is detected in advance using the video signal for flaw detection and the position information is stored and the flaw correction is performed on the video signal of the subject. Therefore, the defect correction process can be performed quickly. That is, compared with the case where a scratch is detected using the video signal before the video signal is corrected, the above video signal processing apparatus detects the scratch in advance. Shortened.

  Also, the video signal processing apparatus of the present invention has a configuration in which the image sensor for flaw detection causes the image sensor to generate a plurality of video signals for flaw detection. Furthermore, the video signal processing apparatus of the present invention includes a scratch statistical processing means for statistically processing, for each pixel, a scratch detected by the scratch detection means from each of the plurality of scratch detection video signals, and the scratch correction The means has a configuration for correcting the video signal of the subject based on the result of statistical processing by the scratch statistical processing means.

  With this configuration, scratched pixels are determined based on the result of statistical processing, so that the detection accuracy of scratches is improved, pixels that are not scratched are corrected, and pixels that are scratched are not corrected. Can be reduced.

  The video signal processing apparatus of the present invention has a configuration in which the flaw detection imaging control means causes the imaging device to generate the flaw detection video signal immediately after power-on.

  With this configuration, a flaw detection video signal is generated immediately after the power is turned on, and information on the position of the flaw is stored, so that the flaw detection of the video signal based on the flaw detection can be performed without hindering normal imaging. The correction can be performed, and the defect correction of the video signal of the subject can be performed immediately after the information on the position of the scratch is stored immediately after the power is turned on.

  In the video signal processing apparatus of the present invention, in order for the flaw detection imaging control means to detect a white flaw of the image sensor, in the exposure control, a flaw that causes a normal pixel to have a luminance value of a predetermined level or less. It has the structure which controls the exposure amount of the said image pick-up element to the exposure amount for a detection.

  Since the pixel value of the white scratch pixel is a high pixel value even when the exposure amount is suppressed, the pixel value of the normal pixel is uniformly lowered and the pixel value of the pixel having a white scratch is also reduced by this configuration. Is extremely expensive. Therefore, it is possible to reduce white defect detection errors and false detections by the flaw detection means. In this exposure control, the exposure may be made zero by closing the aperture completely.

  In the video signal processing apparatus of the present invention, in order for the flaw detection imaging control means to detect black flaws in the image sensor, in the exposure control, flaws in which normal pixels have luminance values equal to or higher than a predetermined level are detected. It has the structure which controls the exposure amount of the said image pick-up element to the exposure amount for a detection.

  Since the output from the black scratched pixel has a low pixel value even when the amount of exposure is large, this configuration makes the pixel value of the normal pixel uniformly high and the pixel value of the black scratched pixel extremely low . Therefore, black defect detection errors and false detections by the flaw detection means can be reduced.

  In the video signal processing apparatus according to the present invention, the flaw detection imaging control means uses a predetermined flaw detection diaphragm as the exposure control.

  The amount of exposure of the image sensor is determined by the aperture and the exposure time. With this configuration, the exposure can be controlled with a simple configuration if the exposure is controlled by the aperture. In addition, when generating a white scratch detection video signal in the first frame immediately after the power is turned on, if the iris is closed before the power is turned on, the white scratch detection image is not activated after the power is turned on. Since the signal can be generated, it is considered that the time required for the operation of the diaphragm is not necessary, and thereby the time required for detecting the scratch is shortened.

  In the video signal processing apparatus of the present invention, the flaw detection imaging control means has a configuration in which the exposure time of the image sensor is set to a predetermined flaw detection exposure time as the exposure control.

  With this configuration, even in a simple apparatus that does not have a function of adjusting the aperture, exposure control can be performed so that the exposure amount of the image sensor is the exposure amount for flaw detection. With this configuration, the exposure amount can be sufficiently increased by taking a sufficiently long exposure time. Therefore, even when the amount of light incident on the image sensor is small, it is possible to satisfactorily realize a black scratch detection exposure amount.

  In the video signal processing apparatus according to the present invention, the imaging control means may be configured such that, as the exposure control, the diaphragm has a predetermined scratch detection diaphragm and the exposure time of the imaging element is a predetermined scratch detection exposure time. Have.

  With this configuration, it is possible to perform imaging with a large exposure amount and a small exposure amount suitable for each of white scratches and black scratches by controlling the aperture and the exposure time of the image sensor.

  The video signal processing apparatus according to the present invention further includes an image processing apparatus for performing image processing on the video signal corrected by the defect correcting unit, based on the defect detected by the defect detecting unit. It has a configuration.

  With this configuration, the image processing apparatus can perform image processing in consideration of scratches on the image sensor. In particular, in image processing, high-accuracy image processing can be performed by reducing the weight of a pixel having a scratch (the weight of a pixel having a scratch may be zero).

  In addition, the video signal processing apparatus according to the present invention includes a flaw detection imaging control unit that causes the imaging device to generate a flaw detection video signal under exposure control for obtaining a predetermined signal level, and the flaw detection video signal. Obtained from the image pickup element based on the flaw detection means for detecting a pixel that generates a luminance value different from the predetermined signal level as a flaw in the image pickup element, and the flaw detected by the flaw detection means. And a defect correcting means for correcting the video signal of the subject.

  With this configuration, in the flaw detection video signal, the luminance of the normal pixel has a predetermined signal level corresponding to the exposure control. By detecting an image that generates a different luminance value from this signal level as a flaw, there are fewer flaw detection omissions and false detections, and the flaw correction means can satisfactorily correct the flaw.

  Also, the video signal processing method of the present invention provides a scratch detection that generates a scratch detection video signal in the image sensor under exposure control in which the exposure amount of the image sensor is set to a scratch detection exposure amount for scratch detection. An image pickup step, a scratch detection step for detecting a scratch in the image sensor using the scratch detection video signal, and a scratch detected in the scratch detection step. And a scratch correction step for correcting the video signal of the subject.

  With this configuration, a defect detection video signal is generated by the image sensor under exposure control in which the exposure amount of the image sensor is set to a defect detection exposure amount for defect detection. In the flaw detection step, it is possible to detect the presence or absence of flaws based on whether or not a normal pixel luminance value is obtained under a flaw detection exposure amount. Therefore, detection defects and erroneous detection of scratches are reduced, and the video signal of the subject can be satisfactorily corrected.

  The video signal processing method of the present invention has a configuration in which the flaw detection imaging step is performed immediately after power-on.

  With this configuration, a flaw detection video signal is generated immediately after the power is turned on, and information on the position of the flaw is stored, so that the flaw detection of the video signal based on the flaw detection can be performed without hindering normal imaging. The correction can be performed, and the defect correction of the video signal of the subject can be performed immediately after the information on the position of the scratch is stored immediately after the power is turned on.

  In the video signal processing method of the present invention, a plurality of video signals for detecting a scratch are generated in the scratch detection imaging step. The video signal processing method of the present invention further includes a scratch statistical processing step for statistically processing the scratches detected in the scratch detection step from each of the plurality of scratch detection video signals for each pixel, The correcting step has a configuration for correcting the video signal of the subject based on the result of the statistical processing.

  With this configuration, scratched pixels are determined based on the result of statistical processing, so that the detection accuracy of scratches is improved, pixels that are not scratched are corrected, and pixels that are scratched are not corrected. Can be reduced.

  The present invention detects scratches on an image sensor by detecting scratches on the image sensor using an image signal for scratch detection generated under exposure control in which the exposure amount of the image sensor is set to an exposure amount for detecting scratches. Therefore, it is possible to provide a video signal processing apparatus that has an excellent effect of reducing the detection omissions and false detections, making it possible to satisfactorily perform defect correction, and to obtain a video signal that is less affected by scratches.

  A video signal processing apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram showing a video signal processing apparatus according to the first embodiment of the present invention.
In FIG. 1, a video signal processing apparatus 1 is a digital video camera that includes a lens 10, a diaphragm 11, an image sensor 12, a preprocessing unit 13, an A / D converter 14, and an imaging control unit 19. The lens 10 collects light from the subject and performs focus adjustment. The diaphragm 11 allows the light transmitted through the lens 10 to pass through the aperture to the image sensor 12. The diaphragm 11 has a mechanism for adjusting its opening diameter. The image sensor 12 is composed of a large number of pixels arranged on a plane, and converts the light received by each pixel into an analog electrical signal. The electric signal is output from the image sensor 12 as an analog video signal. The pre-processing unit 13 is a CDS circuit that removes reset noise of the analog video signal output from the image sensor 12, and an AGC circuit that performs amplitude adjustment so that the analog video signal from which the noise component is removed maintains a constant signal level. , And a circuit that clamps the analog video signal whose amplitude has been adjusted for A / D conversion. The A / D converter 14 converts the analog video signal output from the preprocessing unit 13 into a digital video signal.

  The imaging control unit 19 performs control necessary for imaging such as driving of the lens 10, the diaphragm 11, the imaging device 12, the preprocessing unit 13 and the A / D converter 14, and flash emission, and generates a video signal. At this time, the exposure amount of the image sensor 12 increases as the aperture 11 increases, and the exposure amount of the image sensor 12 increases as the exposure time in the imaging process of the image sensor 12 increases. The imaging control unit 19 includes an aperture control unit 191 and an imaging element driving unit 192. The imaging control for detecting scratches using the aperture control unit 191 and the image sensor driving unit 192 will be described later.

  The video signal processing apparatus 1 includes a flaw detection unit 15 and a flaw position information storage unit 16. The scratch detection unit 15 detects a scratch on the image sensor 12 using the video signal output from the A / D converter 14. The flaw detection unit 15 generates a flaw detection information signal S15 indicating which pixel is flawed based on the detection result.

  FIG. 2 shows the configuration of the scratch detection unit 15. The video signal input from the A / D converter 14 to the scratch detection unit 15 is input to the comparator 31 for each pixel. The scratch detection unit 15 is set with a pixel value threshold for detecting scratches. The comparator 31 compares the pixel value of the input video signal with a threshold value for each pixel.

  When the input pixel value is equal to or greater than the threshold value, the comparator 31 outputs an “H” signal indicating that there is a scratch. Conversely, when the input pixel value is less than the threshold value, the comparator 31 outputs an “L” signal indicating that the pixel is a normal pixel. In this way, the scratch detection unit 15 outputs an “H” or “L” signal for each pixel as the scratch detection information signal S15 for the video signal of one frame. The setting of the threshold value of the scratch detection unit 15 will be described later.

  FIG. 3 is a block diagram illustrating a configuration of another example of the scratch detection unit 15. As shown in FIG. 3, the video signal input from the A / D converter 14 to the defect detection unit 15 sequentially passes through flip-flops (hereinafter referred to as “FF”) 41 and 42 for each pixel. The output of the FF 41 in the previous stage is set as the pixel value Yn of the target pixel, and the pixel values Yn−1 and Yn + 1 of the preceding and following pixels are obtained from the output from the FF 42 and the input to the FF 41, respectively. Then, a difference between adjacent pixels is generated by the adder 43 and the adder 44 and compared with a threshold value by the comparator 45 and the comparator 46. Specifically, the adder 43 adds the pixel value Yn of the pixel of interest and the value obtained by reversing the positive / negative of the pixel value Yn-1 of the previous pixel to generate a difference between the two pixel values. The difference is compared with the threshold value A by the comparator 45. Similarly, the adder 44 adds the pixel value Yn of the pixel of interest and the value obtained by reversing the positive / negative of the pixel value Yn + 1 of the pixel one pixel after the pixel of interest. , And the comparator 46 compares the difference with the threshold value B.

  The outputs of the comparator 45 and the comparator 46 are input to the AND circuit 47. When the difference between Yn and Yn−1 and the difference between Yn and Yn + 1 are both greater than the threshold value, the output of the AND circuit 47 is “H”, and the target pixel is detected as a scratch. When at least one of the difference between Yn and Yn−1 and the difference between Yn and Yn + 1 is smaller than the threshold value, the output of the AND circuit 47 is “L”, and the target pixel is regarded as a normal pixel. It is. The flaw detection unit 15 outputs a flaw detection information signal S15 indicating whether each pixel of interest is a flawed pixel or a normal pixel.

  Then, the flaw position information storage unit 16 takes in a flaw detection information signal S15 output from the flaw detection unit 15 based on an imaging control information signal S19 described later. Here, the scratch detection unit 15 outputs a signal indicating “H” or “L” for each pixel in the order corresponding to the pixel position as the scratch detection information signal S15. Therefore, the flaw position information storage unit 16 stores “H” or “L” information for each pixel in a state where the position of the pixel is known. The signal stored in this way is the flaw position information signal S16.

  The video signal processing apparatus 1 further includes a scratch correction unit 17. The scratch correction unit 17 fetches the video signal of the subject to be corrected from the A / D converter 14 and scratches the video signal to be corrected based on the scratch position information signal S16 stored in the scratch position information storage unit 16. to correct.

  FIG. 4 is a block diagram showing the configuration of the scratch correction unit 17. The video signal of the subject input from the A / D converter 14 to the defect correcting unit 17 sequentially passes through the FFs 51 and 52 for each pixel. The output of the FF 51 in the previous stage is set as the pixel value Yn of the target pixel, and the pixel values Yn−1 and Yn + 1 of the preceding and following pixels are obtained from the output from the FF 52 and the input to the FF 51, respectively. Pixel values Yn−1 and Yn + 1 of the pixels before and after the target pixel are added by the adder 53 and are halved by the divider 54. That is, the output from the divider 54 is the average value of the pixels before and after the target pixel, and this is the corrected pixel value of the target pixel.

  From the defect correcting unit 17, the selector 55 outputs either the pixel value Yn or the corrected pixel value of the target pixel. The flaw position information signal S16 is input to the selector 55 from the flaw position information storage unit 16. The selector 55 operates according to the flaw position information signal S16. If the signal is “H” for each pixel of interest, the selector 55 outputs the corrected pixel value from the divider 54, and if the signal is “L”, The pixel value Yn of the target pixel input from the A / D converter 14 is output as it is.

  As shown in FIG. 1, the video signal processing apparatus 1 further includes a camera process unit 18. The camera process unit 18 performs processing such as luminance signal generation and color difference signal generation on the video signal that has been flaw corrected by the flaw correction unit 17.

The operation of the video signal processing apparatus configured as described above will be described.
FIG. 5 is a diagram illustrating a relationship between time (frame) and the aperture of the diaphragm 11 according to the first embodiment. In the present embodiment, processing for detecting white flaws of the image sensor 12 is performed by image pickup control for detecting flaws by the image pickup control unit 19. As shown in FIG. 5, when the power is turned on, first, the first frame is set as a white flaw detection period. In this white flaw detection period, exposure control is performed so that the exposure amount of the image sensor 12 is a flaw detection exposure amount for white flaw detection.

  In this white scratch detection period, the aperture controller 191 sets the aperture 11 as a scratch detection aperture and generates a video signal. That is, the diaphragm 11 is completely closed by the diaphragm controller 191, and the image signal is generated by the image sensor 12 with the exposure of the image sensor 12 being almost zero. In the second and subsequent frames, the aperture 11 has a standard aperture diameter, and the image signal of the subject is generated by the image sensor 12. As described above, the image pickup control means 19 for causing the image pickup device 12 to pick up an image after performing exposure control to set the exposure amount of the image pickup device 12 to the exposure amount for detecting a flaw for white flaw detection is used for flaw detection according to the present invention. This corresponds to the imaging control means.

  A video signal (hereinafter, referred to as “white scratch detection video signal”) obtained by the imaging control by the imaging control unit 19 during the white scratch detection period is input from the A / D converter 14 to the scratch detection unit 15 and is scratched. It becomes an object of detection. The flaw detection unit 15 detects flaws for each pixel using the white flaw detection video signal and outputs a flaw detection information signal S15 indicating the presence or absence of flaws. The imaging control unit 19 outputs an imaging control information signal S19 indicating that it is a white defect detection period during the white defect detection period. Upon receiving the imaging control information signal S19, the scratch position information storage unit 16 takes in the scratch detection information signal S15 from the scratch detection unit 15 and stores it as a scratch position information signal S16.

  In normal imaging after the second frame, the video signal of the subject obtained by the image sensor 12 is input from the A / D converter 14 to the defect correction unit 17 and is subjected to defect correction. The scratch correction unit 17 performs correction based on the scratches detected by the scratch detection unit 15 in accordance with the scratch position information signal S16 stored in the scratch position information storage unit 16.

  As described above, in the present embodiment, the scratch detection is performed by generating the white scratch detection video signal using the first frame immediately after the power is turned on, and the scratch position information storage unit 16 stores the scratch position information. Thereafter, using the flaw position information signal S16 stored in the flaw position information storage unit 16, the flaw correction of the video signal of the subject can be performed. Therefore, it is possible to perform defect correction using the defect position information from the second frame immediately after the power is turned on.

  FIG. 6 is a diagram showing a white flaw detection video signal. In the white defect detection period, the diaphragm 11 is closed, so that it is in an underexposed state. If it is a normal pixel, its signal level, that is, the pixel value is only about 10. On the other hand, the pixel value of white scratches is about 1000 even though the aperture 11 is closed. As described above, since the diaphragm 11 is closed during the white defect detection period, the difference between the pixel values of the white defect pixel and the normal pixel is sufficiently large. Therefore, if such a white flaw detection video signal is used, flaw detection omission and false detection can be reduced.

  Here, referring to FIG. 13 again, the present embodiment is compared with the conventional example.

  First, in the conventional case, a pixel with white scratches may become a high-luminance portion of the video signal. In this case, the pixel value is about 900, for example, as shown in FIG. In such a case, it is conceivable to set the threshold value as high as 900 or more. However, if the difference between the normal pixel and the scratched pixel and the pixel value is small, accurate scratch detection is difficult.

  On the other hand, in the present embodiment, since a defect detection video signal that has been imaged in an underexposed state during the white defect detection period is used, if it is a normal pixel, for example, as shown in FIG. The signal level is about 10. Therefore, a pixel that greatly exceeds the signal level may be detected as a white defect. The threshold value may be set to 100, for example. As described above, in this embodiment, by using the flaw detection video signal, it is possible to eliminate the influence on the measurement accuracy of the high-brightness portion of the video signal as in the related art and improve the detection accuracy. In the case of the present embodiment, white scratches can be reliably detected even with a simple configuration as shown in FIG.

  In addition, the present embodiment is advantageous compared to the conventional example even when the scratch detection unit 15 has the same configuration as that of the prior art, that is, the configuration shown in FIG.

  In the configuration of the flaw detection unit 15 shown in FIG. 2, the absolute value of the pixel value is compared with the threshold value, whereas in the configuration shown in FIG. 3, the difference in pixel value between adjacent pixels is calculated. The presence or absence of a flaw is determined by comparing with a threshold value. In the example of FIG. 13, since the difference between a pixel with white defects and a normal pixel is only about 100, the threshold value is 100 or less. However, if the threshold value is small, it is easy to cause flaw detection omission and erroneous detection, and it is difficult to detect flaws with high accuracy.

  On the other hand, in the present embodiment, the white scratch detection video signal is generated in a state where the aperture 11 is closed and exposure is suppressed. If the white scratch detection video signal is a normal pixel, the pixel value is about 10, for example, and the white scratch pixel has a pixel value of about 1000 regardless of exposure. Therefore, as shown in FIG. 6, there is no high luminance portion in the video signal, and the difference in pixel value between the normal pixel and the white defect pixel is as large as about 1000. Therefore, when the flaw detection unit 15 is configured as shown in FIG. 3, that is, when the flaw detection unit 15 is configured to detect white flaws by evaluating the difference in pixel values between adjacent pixels, as in the conventional example, If the threshold value of the difference between pixels for detection as a flaw is set to 500, for example, a white flaw pixel with a difference of about 1000 from the pixel value of the adjacent normal pixel can be reliably detected. For example, when the threshold value is set to 500, even if the difference between the pixel values of normal pixels is about 400, such normal pixels are detected as white scratched pixels. False detection can be prevented.

  As described above, in the present embodiment, detection defects and erroneous detection of white scratches are reduced, and highly accurate scratch detection is possible. Further, the scratch correction unit 17 can perform highly accurate scratch correction on the video signal of the subject in the second and subsequent frames based on such highly accurate scratch detection. The camera process unit 18 can perform processing such as generation of a luminance signal and generation of a color difference signal based on a video signal in which white flaws are accurately corrected. Therefore, a good video signal of the subject can be obtained from the video signal processing apparatus 1 as the output of the camera process unit 18.

  In the above example, the iris 11 is completely closed during the white defect detection period, and the white scratch detection video signal is generated with the exposure amount being almost zero. However, an underexposed state can be realized, and normal pixels and If the difference in pixel value from the white scratch pixel is sufficiently large, the diaphragm 11 may be opened. In the above example, the underexposure state is created by closing the aperture 11, but the exposure control of the present invention is not limited to this, and the underexposure state may be realized by closing the lens cover. .

(Second Embodiment)
FIG. 7 is a block diagram showing a video signal processing apparatus according to the second embodiment of the present invention.
In the video signal processing device 2 shown in FIG. 7, the description of the same configuration as that of the video signal processing device 1 of the first embodiment shown in FIG. 1 is omitted.

  In the video signal processing device 2 of the present embodiment, the scratch detection unit 15 includes a white scratch detection unit 151 and a black scratch detection unit 152, and detects both white scratches and black scratches. The white flaw detection unit 151 has the same configuration as that of the flaw detection unit 15 of the first embodiment, and has the configuration shown in FIG. 2 or FIG.

  Also, the black scratch detection unit 152 has the configuration shown in FIG. 2 or FIG. 3 except for the following points. First, when the black scratch detection unit 152 has the configuration shown in FIG. 2, the comparator 31 indicates that there is a black scratch when the input value is lower than the set threshold value. An “H” signal is output, and when the input value is higher than a set threshold value, an “L” signal indicating a normal pixel is output. When the black defect detection unit 152 has the configuration shown in FIG. 3, the adder 43 and the adder 44 generate a difference between adjacent pixels. Specifically, the adder 43 adds a value obtained by reversing the positive / negative of the pixel value Yn of the target pixel and the pixel value Yn−1 of the previous pixel to generate a difference between the two pixels, and adds Similarly, the unit 44 adds a value obtained by reversing the positive / negative of the pixel value Yn of the target pixel and the pixel value Yn + 1 one pixel after that to generate a difference between the two pixels. The AND circuit 47 outputs an “H” signal indicating black flaws when the outputs from the adders 43 and 44 both exceed the threshold values in the comparison by the comparators 45 and 46. In the comparison by the comparators 45 and 46, when at least one of the outputs from the adders 43 and 44 is lower than the threshold value, an “L” signal indicating a normal pixel is output.

  FIG. 8 is a diagram showing the relationship between time (frame) and the aperture of the diaphragm 11 in the second embodiment. In the present embodiment, as shown in FIG. 8, when the power is turned on, the first frame is set to the white defect detection period and the second frame is then detected to the black defect by the control of the imaging control unit 19. The period is set, and the normal imaging state is set after the third frame. In the white scratch detection period, as in the first embodiment, exposure control is performed so that the exposure amount of the image sensor 12 is set to a scratch detection exposure amount for white scratch detection. In the black flaw detection period, exposure control is performed so that the exposure amount of the image sensor 12 is a flaw detection exposure amount for black flaw detection.

  In this white defect detection period, the diaphragm controller 191 generates a video signal after the diaphragm 11 is set as a diaphragm for detecting white defects. That is, the diaphragm 11 is completely closed by the diaphragm controller 191, and a video signal is generated by the image sensor 12 with the exposure of the image sensor 12 being almost zero. In the black defect detection period, the diaphragm control unit 191 generates a video signal after the diaphragm 11 is set as a diaphragm for detecting black defects. That is, the video signal is generated in the open state in which the aperture 11 is fully opened by the aperture controller 191. In the third and subsequent frames, the aperture 11 has a standard aperture diameter, and a video signal of the subject is generated. Thus, the imaging control means 19 that causes the imaging element 12 to perform imaging after performing exposure control to set the exposure amount of the imaging element 12 to the exposure amount for scratch detection corresponds to the imaging control means for scratch detection of the present invention. .

  A video signal (white scratch detection video signal) obtained by imaging control for white scratch detection by the imaging control unit 19 during the white scratch detection period is input from the A / D converter 14 to the white scratch detection unit 151. It becomes the target of white scratch detection. Then, a video signal (hereinafter referred to as “black scratch detection video signal”) obtained by the imaging control for black scratch detection by the imaging controller 19 during the black scratch detection period is transmitted from the A / D converter 14 to the black scratch. It is input to the detection unit 152 and is a target for black flaw detection.

  The white flaw detection unit 151 detects a white flaw and outputs a white flaw detection information signal S151 indicating the presence or absence of a white flaw for each pixel using the white flaw detection video signal. Similarly, the black flaw detection unit 152 uses the black flaw detection video signal to detect a black flaw and output a black flaw detection information signal S152 indicating the presence or absence of a black flaw for each pixel. The imaging control unit 19 outputs an imaging control information signal S19 indicating the white scratch detection period and the black scratch detection period in each of the white scratch detection period and the black scratch detection period. The scratch position information storage unit 16 receives the imaging control information signal S19, takes in the white scratch detection information signal S151 and the black scratch detection information signal S152 from the white scratch detection unit 151 or the black scratch detection unit 152, and detects the scratch position. Stored as information signal S16.

  Then, in normal imaging after the third frame, the video signal of the subject obtained by the image sensor 12 is input from the A / D converter 14 to the defect correction unit 17 and is subjected to defect correction. The flaw correction unit 17 performs correction based on the white flaw and black flaw detected by the white flaw detection unit 151 and the black flaw detection unit 152 according to the flaw position information signal S16 stored in the flaw position information storage unit 16. .

  As described above, in the present embodiment, the first two frames immediately after the power is turned on are used to generate the white flaw detection video signal and the black flaw detection video signal to detect white flaws and black flaws, and to detect flaw position information. Since the flaw position information is stored in the storage unit 16, the flaw position information stored in the flaw position information storage unit 16 can be used to correct flaws in the video signal of the subject. Therefore, the defect correction using the defect position information can be performed from the third frame immediately after the power is turned on.

  Here, the flaw position information storage unit 16 may store the white flaw detection information signal S151 and the black flaw detection information signal S152 output from the white flaw detection unit 151 and the black flaw detection unit 152 separately. However, both may be stored together. Furthermore, when both are stored together, the scratch position information signal S16 may be information indicating whether each pixel is white, black, or normal, or white and black. It is good also as information which shows whether it is a flawed pixel or a normal pixel, without distinguishing.

  When the flaw position information storage unit 16 stores the white flaw detection information signal S151 and the black flaw detection information signal S152 separately, when the flaw correction unit 17 performs flaw correction on the video signal of the subject. The scratch position information storage unit 16 outputs a scratch position information signal S16 based on the white scratch detection information signal S151 and a scratch position information signal S16 based on the black scratch detection information signal S152 for each pixel. Is done. In the defect correcting unit 17, if any one of the defect position information signals S16 is “H” for each pixel, the selector 55 (see FIG. 4) outputs the corrected pixel value.

  On the other hand, when the flaw position information storage unit 16 stores the white flaw detection information signal S151 and the black flaw detection information signal S152 together as a flaw position information signal S16, the flaw correction unit 17 takes an image of the subject. When correcting the flaws in the signal, the flaw position information storage unit 16 outputs a flaw position information signal S16 in the same manner as in the first embodiment. In the defect correcting unit 17, the selector 55 outputs, for each pixel, either the pixel value or the corrected pixel value of the target pixel based on the defect position information signal S16.

  FIG. 9 is a diagram illustrating a video signal for black defect detection. In the black defect detection period, the diaphragm 11 is opened and overexposed, so that the signal level, that is, the pixel value is about 1000 for a normal pixel. On the other hand, the pixel value of a pixel with black scratches is only about 10, for example, although the aperture 11 is open. Therefore, the difference in pixel value between the black scratched pixel and the normal pixel is sufficiently large. Therefore, if such a black scratch detection video signal is used, it is possible to reduce detection omissions and false detections of scratches.

  Here, referring to FIG. 14 again, the present embodiment is compared with the conventional example.

  First, in the conventional case, a black scratched pixel may become a low-luminance portion of a video signal. In this case, the pixel value is about 50, for example, as shown in FIG. In such a case, it is conceivable to set the threshold value as low as 40 or less, for example. However, if the difference between the pixel values of normal pixels and scratched pixels is small, accurate scratch detection is difficult.

  On the other hand, in the present embodiment, since a video signal for black defect detection that is imaged in an overexposed state during the black defect detection period is used, if it is a normal pixel, for example, as shown in FIG. The signal level is about 1000. Therefore, a pixel that greatly falls below this signal level may be detected as a black defect. The threshold value may be set to 100, for example. As described above, in this embodiment, by using the black scratch detection video signal, it is possible to eliminate the influence on the measurement accuracy of the low-brightness portion of the video signal as in the related art and improve the detection accuracy. In the case of the present embodiment, black scratches can be reliably detected even with a simple configuration as shown in FIG.

  In addition, the present embodiment is advantageous in comparison with the conventional example even when the black scratch detection unit 152 has the same configuration as that of the prior art, that is, the configuration shown in FIG.

  In the configuration shown in FIG. 2, the absolute value of the pixel value is compared with the threshold value, whereas in the configuration shown in FIG. 3, the difference in pixel value between adjacent pixels is compared with the threshold value. By doing so, it is determined whether or not it is a scratch. In the example of FIG. 14, since the difference between a pixel with black scratches and a normal pixel is only about 40, the threshold value is 40 or less. However, if the threshold value is small, it is easy to cause flaw detection omission and erroneous detection, and it is difficult to detect flaws with high accuracy.

  In contrast, in the present embodiment, the black scratch detection video signal is generated with the aperture 11 opened and the exposure increased. If the black scratch detection video signal is a normal pixel, the pixel value is about 1000, for example, and the black scratch pixel has a pixel value of about 10 regardless of exposure. Therefore, as shown in FIG. 9, there is no body luminance portion in the video signal, and the difference in pixel value between the normal pixel and the black scratched pixel is as large as about 1000. Therefore, when the black scratch detection unit 152 is configured as shown in FIG. 3, that is, when the black scratch is detected by evaluating the difference in pixel values between adjacent pixels as in the conventional example, If the threshold value of the difference between pixels for detection as a black defect is set to 500, for example, a black defect pixel with a difference of about 1000 from the pixel value of the adjacent normal pixel can be reliably detected. For example, if the threshold value is set to 500, even if the difference between the pixel values of normal pixels is about 400, such normal pixels are detected as black scratched pixels. False detection can be prevented.

  In the above example, in the black scratch detection period, the aperture control unit 191 of the imaging control unit 19 performs control to generate the black scratch detection video signal by setting the aperture 11 to the black scratch detection aperture (open). It was. However, even if the aperture 11 is fully opened, the amount of incident light is not sufficient, and it may not be possible to obtain exposure sufficient to increase the pixel value of normal pixels. In view of this, the image sensor drive unit 192 of the image capturing control unit 19 may set the image capturing time of the image sensor 12 to the black scratch detecting exposure time during the black defect detection period, thereby creating an overexposed state. That is, in the black scratch detection period, the image sensor drive unit 192 may control to increase the exposure time of the image sensor 12. Of course, after the aperture 11 is opened by the aperture controller 191, the image sensor drive unit 192 may control to increase the exposure time of the image sensor 12. Further, a flash may be emitted in order to create an overexposed state during the black scratch detection period. Thereby, it is possible to increase the exposure amount more reliably regardless of the external brightness.

  In addition, during the white defect detection period, the image sensor driving unit 192 may generate the white defect detection signal by setting the imaging time of the image sensor 12 to the exposure time for white defect detection. This exposure control is particularly effective when the diaphragm 11 does not have a mechanism for adjusting the aperture diameter, and exposure cannot be adjusted by the diaphragm 11. In this case, the image sensor drive unit 192 causes the image sensor 12 to perform photoelectric conversion processing with an exposure time of zero during the white flaw detection period. In this case, the exposure time may not be zero as long as a sufficiently underexposed state can be realized.

  As described above, according to the second embodiment, the white flaw detection video signal and the black flaw detection video signal are generated by controlling the exposure time of the diaphragm 11 and / or the image sensor 12. In addition, it is possible to perform highly accurate flaw correction by reducing detection errors and false detection of black flaws.

(Third embodiment)
FIG. 10 is a block diagram showing a video signal processing apparatus according to the third embodiment of the present invention.
In the video signal processing device 3 shown in FIG. 10, the description of the same configuration as that of the above-described video signal processing device is omitted.

  Similar to the video signal processing device 2 of the second embodiment, the scratch detection unit 15 of the video signal processing device 3 includes a white scratch detection unit 151 and a black scratch detection unit 152.

  FIG. 11 is a diagram illustrating a relationship between time (frame) and the aperture of the diaphragm 11 according to the third embodiment. In the present embodiment, the imaging control unit 19 causes the imaging device 12 to generate a plurality of white scratch detection video signals and a plurality of black scratch detection video signals. That is, as shown in FIG. 11, when the power is turned on, the first frame is set as a white flaw detection period and the second frame is set as a black flaw detection period under the control of the imaging control unit 19. In the frame and the fourth frame, the white flaw detection period and the black flaw detection period are set again. Then, the normal imaging state is set after the fifth frame. As a result, the image sensor 12 generates two white scratch detection video signals and two black scratch detection video signals.

  In the white flaw detection period and the black flaw detection period, respectively, in the same manner as in the above-described embodiment, the image pickup control unit 19 performs white flaw detection video signals in the image sensor 12 under exposure control for flaw detection. In addition, a video signal for black defect detection is generated. In the present embodiment, the imaging control unit 19 that causes the image sensor 12 to generate the white scratch detection video signal and the black scratch detection video signal in the period of 4 frames immediately after the power is turned on is the scratch detection imaging control according to the present invention. Corresponds to means.

  The white flaw detection video signal and the black flaw detection video signal are input to the white flaw detection unit 151 and the black flaw detection unit 152, respectively. The white flaw detection unit 151 detects white flaws using the white flaw detection video signal in the same manner as in the second embodiment, and the black flaw detection unit 152 also performs black flaws in the same manner as in the second embodiment. Black scratches are detected using the detection video signal. The flaw position information storage unit 16 stores a flaw position information signal S16 based on the white flaw detection information signal S151 and the black flaw detection information signal S152 output from the white flaw detection unit 151 and the black flaw detection unit 152. In the present embodiment, since two white scratch detection video signals and two black scratch detection video signals are generated, the scratch position information storage unit 16 stores information indicating the presence or absence of white scratches for each pixel. Information indicating the presence or absence of black flaws is stored for two frames each.

  The video signal processing apparatus 3 according to the present embodiment includes a scratch probability calculation unit 20. The flaw establishment calculation unit 20 corresponds to a flaw statistical processing unit of the present invention, and obtains a flaw occurrence probability for each pixel in a plurality of flaw position information signals S16 output from the flaw position information storage unit 16, and a flaw correction unit At 17, the pixel to be corrected for scratches is determined.

  The flaw probability calculation unit 20 takes in and stores a flaw position information signal S16 from the flaw position information storage unit 16. Then, the appearance probability of white scratches is calculated for each pixel using the white scratch position information signal S16 for two frames, and the black scratch position information signal S16 for two frames is used for each pixel. Calculate the appearance probability of scratches. The scratch probability calculation unit 20 determines each pixel as a pixel to be corrected by the scratch correction unit 17 when both of the scratch position information signals S16 for two frames indicate a scratch. In other words, pixels detected as scratches in both of the two scratch detections by the scratch detection unit 15 are set as correction targets. The scratch probability calculation unit 20 outputs a scratch probability position information signal S20 indicating whether or not each pixel is a correction target to the scratch correction unit 17. The scratch probability position information signal S20 is a signal indicating “H” for each pixel and “L” for each pixel.

  The scratch probability position information signal S20 is generated for each of white scratches and black scratches. The scratch probability position information signal S20 may be a signal that collectively indicates white scratches and black scratches. In this case, in the scratch probability position information signal S20, pixels detected as white scratches twice by the white scratch detection unit 151 and pixels detected as black scratches twice by the black scratch detection unit 152 become “H”. .

  The scratch correction unit 17 takes in the video signal of the subject from the A / D converter 14 and controls the selector 55 (see FIG. 4) by the scratch probability position information signal S20 from the scratch probability calculation unit 20 to thereby detect the video signal of the subject. Perform scratch correction. Here, it is assumed that the scratch probability position information signal S20 is a signal that collectively indicates the above-described white scratch and black scratch. In this case, for each pixel, if the scratch probability position information signal S20 is “H”, the selector 55 outputs the pixel value of the target pixel as it is, and if the scratch probability position information signal S20 is “L”. The corrected pixel value is output. On the other hand, when the scratch probability position information signal S20 is generated separately for white scratches and black scratches, the selector 55 sends a white scratch probability position information signal and black scratch probability position to each pixel. Both information signals are input. Then, when any scratch probability position information signal is “H”, the selector 55 outputs a corrected pixel value for the pixel.

  As described above, in the video signal processing device 3 according to the present embodiment, the imaging control unit 19 causes the image sensor 12 to generate a plurality of white scratch detection video signals and a plurality of black scratch detection video signals. The scratch probability for the scratch correction unit 17 to correct the scratch based on the scratch position information signal S16 indicating the position of the scratch detected from the multiple scratch detection video signals. The position information signal S20 is output. The scratch correction unit 17 performs scratch correction of the video signal based on the scratch probability position information signal S20. Accordingly, it is possible to reduce improper flaw correction due to flaw detection omission or erroneous detection, and to perform good flaw correction.

  Here, in the above example, the scratch probability calculation unit 20 generates a scratch probability position information signal in which the pixel detected as a scratch is “H” in both of the two scratch detection video signals. That is, a pixel having a scratch occurrence probability of 100% is set as a defect correction target. Therefore, the possibility of erroneously detecting a pixel that is not a flaw as a flaw is reduced. As a modification, the scratch calculation unit 20 may generate a scratch probability position information signal that sets the pixel to “H” when a scratch is detected in one of the two scratch detection video signals. In this case, it is possible to reduce the possibility of excluding a pixel that is a flaw as a flaw-corrected object because it is not a flaw. As described above, according to the present embodiment, the probability of erroneously determining a defective pixel as a normal pixel and the opposite probability can be adjusted depending on whether the generation probability of the criterion for defect determination is set high or low.

  In addition, as in the above example, the scratch probability calculation unit 20 uses a pixel detected as a scratch in both of the two scratch detection video signals as a scratch correction target. It may be composed of an AND circuit. When a pixel detected as a scratch in one of the two scratch detection video signals is to be subjected to scratch correction, the scratch probability calculation unit 20 may be configured by an OR circuit.

  Further, in the above example, two white scratch detection video signals and two black scratch detection video signals are generated by using the four frames immediately after entering the power supply town under the control of the imaging control unit 19. Is not limited to this. Three or more white flaw detection video signals and black flaw detection video signals may be generated, or all the flaw detection video signals may not be generated immediately after power-on.

  The scratch probability calculating unit 20 corresponds to the scratch statistical processing means of the present invention, but the scratch statistical processing means of the present invention is a plurality of scratch detection information signals obtained by scratch detection using a plurality of scratch detection video signals. If the result of the flaw detection for each pixel is statistically processed using, and it is determined whether or not to be a flaw correction target for each pixel, the flaw correction is performed according to the flaw occurrence probability as in the above example. It is not restricted to what determines whether it is made the object of.

  Note that the scratch probability calculation unit 20 may be disposed between the scratch detection unit 15 and the scratch position information storage unit 16. In this case, the scratch probability calculation unit 20 obtains the scratch occurrence probability in the same manner as described above using the scratch detection information signal S15 output from the scratch detection unit 15, and determines whether or not each pixel is subject to scratch correction. A scratch probability position information signal S20 indicating whether or not is output. The scratch position information storage unit 16 stores the scratch probability position information signal S20 output from the scratch probability calculation unit 20 as a scratch position information signal S16, and the scratch correction unit 17 is output from the scratch position information storage unit 16. The video signal is corrected based on the scratch position information signal S16. With this configuration, the scratch probability calculation unit 20 does not need to calculate the scratch probability every time the video signal of the subject is corrected for scratches, so that the processing load for scratch correction is reduced.

(Fourth embodiment)
FIG. 12 is a block diagram showing a video signal processing apparatus according to the fourth embodiment of the present invention.
In the video signal processing device 4 shown in FIG. 12, the description of the same configuration as that of the above-described video signal processing device is omitted.

  The video signal processing device 4 of the present embodiment includes an image processing device 21. The video signal output from the camera process unit 18 is input to the image processing device 21. The image processing device 21 performs image processing such as image recognition processing for identifying a specific subject portion from the image or identifying the content of the subject in the image, image editing processing, and image data compression processing. Device.

  The video signal processing device 4 includes a scratch probability calculating unit 20 as in the third embodiment. The scratch detection unit 15 also includes a white scratch detection unit 151 and a black scratch detection unit 152 as in the third embodiment. Under the control of the imaging control unit 19, the image sensor 12 generates a white flaw detection video signal and a black flaw detection video signal, and then the flaw probability calculation unit 20 generates a flaw probability position information signal S 20. The processes up to are the same as in the third embodiment.

  In the present embodiment, the scratch probability position information signal S20 generated by the scratch probability calculation unit 20, that is, a signal indicating which pixel is the target of the scratch correction is not limited to the scratch correction unit 17. The image processing device 21 is also incorporated. Then, the image processing device 21 performs image processing such as image recognition and editing on the video signal taken from the camera process unit 18 using the scratch probability position information signal S20. At this time, the image processing apparatus 21 may perform image processing by excluding pixels that are “H” in the scratch probability position information signal, or to image processing of pixels that are “H” in the scratch probability position information signal. Image processing may be performed with a weighting coefficient used in image processing lower than that of other normal pixels so that the degree of influence of the image becomes lower.

  According to the present embodiment, it is possible to perform highly accurate image processing by using the image processing device 21 with information on the position of the scratch used for correcting the scratch.

  In the fourth embodiment, the video signal processing device 4 includes a scratch probability calculation unit 20 as in the video signal processing device 3 of the third embodiment, and the image processing device 21 calculates the scratch probability. The image processing is performed using the scratch probability position information signal S20 output from the unit 20, but the video signal processing device 4 is scratched as in the first embodiment or the second embodiment. The probability calculating unit 20 may not be provided. In this case, the flaw position information storage unit 16 outputs a flaw position information signal S16 to the image processing device 21. Further, even when the video signal processing apparatus includes the scratch probability calculating unit 20, the image processing device 21 performs image processing using the scratch position information signal S16 output from the scratch position information storage unit 16. It's okay.

  As described above, according to the present embodiment, under the exposure control in which the exposure amount of the image sensor 12 is set to the exposure amount for detecting scratches by the imaging control for the defect detection by the imaging control unit 19. Thus, the image sensor 12 generates a scratch detection video signal. Then, the flaw detection unit 15 detects the presence or absence of flaws depending on whether or not a normal pixel luminance value under a flaw detection exposure amount is obtained. Therefore, detection defects and erroneous detection of scratches are reduced, and the video signal of the subject can be satisfactorily corrected.

  In the first to fourth embodiments described above, the imaging control unit 19 controls the detection period or normal imaging in units of frames. However, the imaging control unit 19 performs this control. May be performed on a field basis.

  Further, the method of correcting the scratch by the scratch correcting unit 17 is not limited to the above-described embodiment, and any known method may be used. For example, the median value of eight pixels around the correction target pixel is set as the corrected pixel value. May be corrected as follows.

  In the first to fourth embodiments, the video signal processing apparatus is a digital video camera that captures moving images. However, the video signal processing apparatus of the present invention is a digital video camera that captures still images. It may be a still camera. Further, the video signal processing apparatus may be a single-plate camera provided with only one image sensor or a three-plate camera provided with an image sensor for each RGB color.

  As described above, the video signal processing apparatus according to the present invention is excellent in that a video signal with little influence of scratches can be obtained because defect detection errors and false detections are reduced and defect correction can be performed satisfactorily. It has an effect and is useful as a digital still camera, a digital video camera or the like.

1 is a block diagram of a video signal processing apparatus according to a first embodiment of the present invention. The figure which shows the structure of the crack detection part in embodiment of this invention. The block diagram which shows the other structural example of the crack detection part in embodiment of this invention The block diagram which shows the structure of the crack correction | amendment part in embodiment of this invention The figure which shows the relationship between the time (frame) in 1st Embodiment of this invention, and opening of an aperture_diaphragm | restriction. The figure which shows the video signal for white flaw detection in embodiment of this invention The block diagram of the video signal processing apparatus in the 2nd Embodiment of this invention The figure which shows the relationship between the time (frame) in 2nd Embodiment of this invention, and opening of an aperture_diaphragm | restriction. The figure which shows the video signal for black crack detection in embodiment of this invention The block diagram of the video signal processing apparatus in the 3rd Embodiment of this invention The figure which shows the relationship between the time (frame) in 3rd Embodiment of this invention, and opening of an aperture_diaphragm | restriction. The block diagram of the video signal processing apparatus in the 4th Embodiment of this invention The figure which shows the pixel value of a video signal when there is a white crack in the high-intensity part of a video signal in the conventional video signal processing apparatus. The figure which shows the pixel value of a video signal in the case of a black crack in the low-intensity part of a video signal in the conventional video signal processing apparatus.

Explanation of symbols

1, 2, 3, 4 Video signal processing apparatus 11 Aperture 12 Image sensor 15 Scratch detection unit 16 Scratch position information storage unit 17 Scratch correction unit 19 Imaging control unit 20 Scratch probability calculation unit 151 White scratch detection unit 152 Black scratch detection unit 191 Aperture control unit 192 Image sensor drive unit

Claims (14)

A flaw detection imaging control means for causing the image sensor to generate a flaw detection video signal under exposure control in which the exposure amount of the image pickup element is set to a flaw detection exposure amount for flaw detection.
A flaw detection means for detecting a flaw in the image sensor using the flaw detection video signal;
A video signal processing apparatus comprising: a scratch correction unit that corrects a video signal of a subject obtained by the imaging device based on a scratch detected by the scratch detection unit. Flaw position information storage means for storing information on the position of the flaw detected by the flaw detection means,
2. The video signal processing apparatus according to claim 1, wherein the flaw correction unit corrects the video signal of the subject using information on a flaw position stored in the flaw position information storage unit. The flaw detection imaging control means causes the image sensor to generate a plurality of flaw detection video signals,
A scratch statistical processing means for statistically processing, for each pixel, a scratch detected by the scratch detection means from each of the plurality of scratch detection video signals;
The video signal processing apparatus according to claim 1, wherein the scratch correction unit corrects the video signal of the subject based on a result of statistical processing by the scratch statistical processing unit. 4. The video signal processing apparatus according to claim 1, wherein the scratch detection imaging control unit causes the imaging element to generate the scratch detection video signal immediately after power is turned on. In order to detect white flaws in the image pickup device, the flaw detection image pickup control means is configured to reduce the exposure amount of the image pickup device to a flaw detection exposure amount in which a normal pixel generates a luminance value of a predetermined level or less in the exposure control. 5. The video signal processing apparatus according to claim 1, wherein an exposure amount is controlled. The flaw detection imaging control means detects the black flaw of the image sensor, and in the exposure control, the flaw detection exposure amount at which a normal pixel generates a luminance value equal to or higher than a predetermined level in the exposure control. 5. The video signal processing apparatus according to claim 1, wherein an exposure amount is controlled. 7. The video signal processing apparatus according to claim 1, wherein the flaw detection imaging control means uses a predetermined flaw detection diaphragm as the exposure control. The video signal according to any one of claims 1 to 6, wherein the flaw detection imaging control means sets the exposure time of the image sensor to a predetermined flaw detection exposure time as the exposure control. Processing equipment. 7. The imaging control unit according to claim 1, wherein the imaging control means uses a predetermined aperture for detecting scratches as the exposure control and sets an exposure time for the imaging device to a predetermined exposure time for detecting scratches. The video signal processing apparatus according to any one of the above. 3. The video according to claim 2, further comprising an image processing device for performing image processing on the video signal corrected by the scratch correction means based on the scratch detected by the scratch detection means. Signal processing device. Under the exposure control for obtaining a predetermined signal level, the image sensor for flaw detection that causes the image sensor to generate a video signal for flaw detection;
Flaw detection means for detecting, as a flaw in the image sensor, a pixel that generates a luminance value different from the predetermined signal level from the flaw detection video signal;
A video signal processing apparatus comprising: a scratch correction unit that corrects a video signal of a subject obtained by the imaging device based on a scratch detected by the scratch detection unit. A flaw detection imaging step for generating a flaw detection video signal in the image sensor under exposure control in which the exposure amount of the image sensor is set to a flaw detection exposure amount for flaw detection;
Using the scratch detection video signal, a scratch detection step of detecting a scratch on the image sensor;
And a flaw correction step of correcting a video signal of a subject obtained by the imaging device based on the flaw detected in the flaw detection step. 13. The video signal processing method according to claim 12, wherein the flaw detection imaging step is performed immediately after the power is turned on. In the scratch detection imaging step, a plurality of scratch detection video signals are generated,
A scratch statistical processing step for statistically processing the scratches detected in the scratch detection step from each of the plurality of scratch detection video signals for each pixel;
14. The video signal processing method according to claim 12, wherein the scratch correction step corrects the video signal of the subject based on the result of the statistical processing.

Images