JP2005191987A - Video signal processor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a video signal processor that generates a successful video signal from which fixed pattern noise is eliminated even during blurring correction processing and that therefore provides a high quality display image without unwanted noise in the case of performing image display based on the above successful video signal. <P>SOLUTION: The video signal processor is provided with: a drive pulse generation circuit 300 which generates drive pulse of a solid-state imaging device 101; a circuit block 210 for generating a signal for correcting the fixed pattern noise, which generates the signal for correcting the fixed pattern noise from an empty feed area signal or a perpendicular optical black area signal or both of them of the solid-state imaging device 101; and a controller 230 which supplies a control signal for transferring an optional effective area signal at high speed to the drive pulse generation circuit 300 after reading the empty feeding area signal or the perpendicular optical black area signal of the solid-state imaging device 101, and the video signal processor generates the signal for correcting the fixed pattern noise from the empty area signal or the perpendicular optical black area signal of the solid-state imaging device 101. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a video signal processing apparatus that performs signal processing on a video output signal from a solid-state imaging element in an imaging apparatus using the solid-state imaging element.

  2. Description of the Related Art Conventionally, in an imaging apparatus using a solid-state imaging device widely used for a video cam, a digital camera, etc., a minute level video signal photoelectrically converted in the imaging device and an amplitude for driving the imaging device Several volt pulses are mixed in the circuit. In addition, various types of pulses and clocks are generally mixed for signal processing in the imaging apparatus system, and they are often signals generated from a common reference clock and synchronized with each other.

  When high-frequency components of these synchronized signals are mixed into the output signal from the image sensor due to capacitive coupling between patterns, etc., it becomes a vertical line-shaped fixed pattern noise that can be seen on the monitor screen, causing deterioration in image quality There is. In particular, since the element output signal level becomes smaller when shooting under low illumination, in order to secure the signal level, it is necessary to amplify several dB to several tens of dB with a subsequent amplifier, and image quality deterioration due to noise. Becomes more prominent.

Therefore, in the past, several video signal processing methods for reducing the influence of the fixed pattern noise have been proposed.
For example, the dark output signal level for all pixels of the solid-state image sensor is stored in a memory, and during normal imaging, the dark output signal corresponding to each pixel is subtracted from the bright output signal level at that time. A typical technique is to cancel the noise component.

  As another proposal (for example, refer to Patent Document 1), a solid-state image pickup device in which an empty feed portion without pixels using only a vertical transfer unit exists like a dummy pixel region shown in FIG. The noise component included in the feed unit output signal is treated as negative data, the (signal + noise) component contained in the effective area signal output is treated as positive data, and these data are added to cancel the noise component. A technique for removing is disclosed.

Further, similarly to the above-described dummy pixel region signal shown in FIG. 2, the vertical optical black region signal whose output signal does not include the video signal component can be handled in the same manner as the blank feeding portion signal. Similar approaches have been proposed.
JP 2000-152098 A

  However, in the conventional video signal processing method as described above, image stabilization of a clipping method in which a part of the signal area of the solid-state image sensor is used as a video signal by performing a part of high-speed transfer processing during vertical scanning of the solid-state image sensor When the system is employed, the idle feed area signal or the vertical optical black area signal is read out by the vertical high-speed transfer process like any effective pixel area signal, and thus cannot be normally extracted.

  Normally, reading from the CCD is performed by scanning each line by making the vertical transfer period for each line coincide with the horizontal transfer period for one line. At this time, when the above-described clipping type image stabilization system is adopted, it is necessary to sweep out the extra line signal at high speed during the vertical blanking period of the system. 10 times and does not match the horizontal transfer cycle. Accordingly, since the signal component for each pixel cannot be read, the horizontal transfer itself is stopped during the vertical high-speed transfer period. For this reason, when the above-described camera shake correction system is employed, the pre-feed area signal or the vertical optical black area signal cannot be properly extracted.

  Therefore, when the above-described camera shake correction system is employed, it is not possible to use a noise removal method using an idle feed area signal or a vertical optical black area signal as described in Patent Document 1 described above. Had problems.

  The present invention solves the above-mentioned conventional problems, and even during a camera shake correction process using a clipping method that performs a part of high-speed transfer processing during vertical scanning of a solid-state imaging device, a good video signal that reliably removes fixed pattern noise is obtained. Provided is a video signal processing apparatus that can generate a high-quality display image with reduced image quality deterioration due to unnecessary noise when an image is displayed based on the video signal.

  In order to solve the above-described problem, a video signal processing apparatus according to claim 1 of the present invention is based on a reference clock for driving the solid-state image sensor with respect to a video signal output from the solid-state image sensor. A video signal processing apparatus for correcting the influence of fixed pattern noise generated by the driving pulse generating means for generating a driving pulse for vertical scanning of the solid-state imaging device based on the reference clock, and the driving pulse generation Correction signal generating means for generating a signal for correcting the fixed pattern noise based on the output signals of the idle feed area and / or the vertical optical black area output from the solid-state imaging device at the period of the drive pulse from the means; , The period of the drive pulse from the drive pulse generating means, the idle feed area of the solid-state imaging device or the vertical optical black A control signal for outputting to the drive pulse generating means a control signal that is shortened for high-speed transfer of an arbitrary effective area signal after reading out the area signal, and the idle feed area signal or the vertical optical black area signal According to the correction signal generated by the correction signal generation means based on the video signal output from the solid-state image sensor according to the drive pulse output from the drive pulse generation means by the control signal from the control means at the time of reading The present invention is characterized in that correction processing for the fixed pattern noise is performed.

  As described above, even when camera shake correction is performed using a clipping-type camera shake correction system that partially performs high-speed transfer processing during vertical scanning of the solid-state image sensor, the solid-state image sensor's idle feed area signal or vertical optical black area signal Reading can be performed, a signal for correcting fixed pattern noise can be generated based on these signals, and correction processing for fixed pattern noise can be performed using the correction signal.

  As described above, according to the present invention, even when camera shake correction is performed using a clipping-type camera shake correction system that partially performs high-speed transfer processing during vertical scanning of the solid-state image sensor, Alternatively, it is possible to read out a vertical optical black area signal, generate a fixed pattern noise correction signal based on these signals, and perform a fixed pattern noise correction process using the correction signal.

  Therefore, even during the camera shake correction process using the clipping method that performs a part of the high-speed transfer process during vertical scanning of the solid-state image sensor, it is possible to generate a good video signal from which fixed pattern noise has been reliably removed. When displaying, it is possible to obtain a high-quality display image with reduced image quality deterioration due to unnecessary noise.

Hereinafter, a video signal processing apparatus according to an embodiment of the present invention will be specifically described with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of a video signal processing apparatus according to the present embodiment. FIG. 2 is a general pixel configuration diagram of the solid-state imaging device 101 in FIG. FIG. 3 is an explanatory diagram of a vertical read operation when a conventional clipping camera shake correction method is used. FIG. 4 is an explanatory diagram of the vertical reading operation of the video signal processing apparatus according to the present embodiment.

  In FIG. 1 and FIG. 4, in the imaging system block 100, an analog signal read from the solid-state imaging device 101 passes through an amplifier 102 and is converted into a digital signal by an A / D converter 103. Reference numeral 200 denotes a circuit block for removing fixed pattern noise included in the output signal of the imaging system block 100. Reference numeral 210 denotes a fixed pattern noise which is inputted with a signal of the idle feed area or the vertical optical black area of the solid-state imaging device 101. This is a circuit block that generates a correction signal for removing. Reference numeral 300 denotes a circuit that generates the driving pulse signal 402 of the solid-state image sensor 101 and the system reference synchronization signal 403 shown in FIG. 230 receives a system reference synchronization signal 403 from the drive pulse generation circuit 300, and a control signal C300 for controlling the cycle of the drive pulse signal 402 from the drive pulse generation circuit 300, or a fixed pattern noise correction signal generation circuit. This is a controller that outputs a control signal C210 for performing timing control for generating a correction signal by the block 210.

  Note that the controller 230 also performs control for selecting and capturing a signal in the idle feeding area or the vertical optical black area of the solid-state imaging device 101 from the output signal from the A / D converter 103.

  3 and 4, the vertical reading period 407 with respect to the cut-out area of the solid-state imaging device 101 is defined by the standard of the entire system. For example, it may be a TV signal standard or a compatible recording medium standard. In FIG. 3, while constantly outputting the required number of lines defined to correspond to the standard, the output ratio of the vertical high-speed transfer pulse signals 404a and 404b is changed, and the area corresponding to the camera shake correction control is cut out and output. . Note that the output period of the vertical reading period 407 matches the period required for horizontal transfer, but the output periods of 404a and 404b do not depend on the horizontal transfer period.

  Next, an operation in which the output signal of the subtracter 220 in FIG. 1 is sent to the subsequent stage as a video signal obtained by removing fixed pattern noise from the output signal of the solid-state imaging device 101 will be described in detail.

  First, when trying to generate a correction signal for removing fixed pattern noise from the output signal of the solid-state imaging device 101, the controller 230 causes the drive pulse generation circuit 300 to respond to the timing of the system reference synchronization signal 403. A control signal C300 for reading out the idle feed portion or vertical OB portion signal of the fixed image sensor 101 is output, and the drive pulse generation circuit 300 stops outputting the vertical high-speed transfer pulse as the drive pulse signal 402 according to the control signal C300. By outputting the normal speed transfer pulse, the imaging system block 100 performs a normal reading operation using the normal speed transfer pulse.

  The above read operation will be described. As shown in FIG. 4, as the drive pulse signal 402, the output of the vertical high-speed transfer signal 404a is temporarily stopped and the normal transfer signal 406 is output. Read the signal 405. Then, after performing a horizontal transfer process and sending it to a subsequent circuit, a high-speed transfer process is performed to sweep out signals of an arbitrary number of lines. In this case, depending on the number of lines subjected to high-speed transfer processing, it may be necessary to control the transfer cycle to be shorter than normal.

  The signal 405 of the idle feed unit or vertical OB unit read out in this way is input to the signal processing circuit 200 in the subsequent stage through the amplifier 102 and the A / D converter 103 shown in FIG. Here, by the timing control of the controller 230, the signal 405 is also input to the fixed pattern noise correction signal generation circuit block 210, stored in the line memory 211, and then subjected to arbitrary gain correction through the amplifier 212. A signal is input to the subtractor 220.

On the other hand, the effective area output signal of the solid-state imaging device 101 is input only to the subtractor 220 without passing through the circuit block 210 by the timing control of the controller 230.
The correction signal output from the correction signal generation circuit block 210 in this way does not include a photoelectrically converted signal component, and corresponds to a fixed pattern noise component that is similarly included in each line of the effective area output signal. By subtracting the effective area output signal for each line in the subtracter 220, a video signal from which fixed pattern noise has been removed is obtained.

  As described above, in the present embodiment, a controller is provided that sends a control signal for stopping the vertical high-speed transfer processing of the solid-state imaging device at a timing as necessary to the drive pulse generation circuit of the solid-state imaging device. Because of this, even when using a clipping-type image stabilization system that partially performs high-speed transfer processing during vertical scanning of the solid-state image sensor, it is possible to correct fixed pattern noise from the idle feed area signal or vertical optical black area signal of the solid-state image sensor. A signal can be generated, and a video signal from which fixed pattern noise has been removed can be obtained even during the above-described camera shake correction processing.

  In the present embodiment, the signal for one line to be stored in the memory 211 is selected by averaging a plurality of lines arbitrarily from the idle feed area signal or the vertical optical black area signal of the solid-state imaging device 101, It is also possible to obtain a correction signal in which the influence of single pixel noise or random noise is reduced.

  In addition, since the system reference synchronization signal 403 output from the drive pulse generation circuit 300 is input to the controller 230, the timing at which the signal of the selected line is input to the fixed pattern noise correction signal generation circuit block 210 is easy. Can be detected.

  The video signal processing apparatus of the present invention can generate a good video signal that reliably removes fixed pattern noise even during camera shake correction processing by a clipping method that performs partial high-speed transfer processing during vertical scanning of a solid-state imaging device, When an image is displayed based on the video signal, a high-quality display image with reduced image quality deterioration due to unnecessary noise can be obtained, and can be applied to an imaging system using a solid-state imaging device.

The block diagram which shows the structure of the video signal processing apparatus of embodiment of this invention 1 is a general pixel configuration diagram of the solid-state imaging device in FIG. Explanatory drawing of the vertical read-out operation at the time of using the clipping camera-shake correction method in the conventional video signal processing apparatus Explanatory drawing of the vertical read-out operation | movement in the video signal processing apparatus of embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Image pickup system circuit block 101 Solid-state image sensor 102 Amplifier 103 A / D converter 200 Fixed pattern noise removal processing circuit block 210 Fixed pattern noise correction signal generation circuit block 211 Line memory 212 Amplifier 220 Subtractor 230 Controller 300 Drive pulse generation circuit 401 Fixed image sensor output signal 402 Vertical drive signal of fixed image sensor 403 System reference synchronization signal 404a Vertical high-speed transfer signal (1) in the vertical drive signal of the solid-state image sensor
404b Vertical high-speed transfer signal (2) in the vertical drive signal of the solid-state image sensor
405 Solid-state image sensor idle feed section or vertical OB section readout signal 406 Solid-state image sensor idle feed section or vertical OB section readout signal 407 Solid-state image sensor vertical direction signal readout period

Claims (1)

  A video signal processing apparatus that corrects the influence of fixed pattern noise generated on the basis of a reference clock for driving the solid-state image pickup device for a video signal output from the solid-state image pickup device. Drive pulse generation means for generating a drive pulse for vertical scanning of the solid-state image sensor based on the idle feed area or vertical optical black area output from the solid-state image sensor at the cycle of the drive pulse from the drive pulse generation means or Based on both output signals, a correction signal generating means for generating a signal for correcting the fixed pattern noise, and a period of the driving pulse from the driving pulse generating means are set to the idle feed region or the vertical direction of the solid-state imaging device. After reading out the signal in the optical black area, shorten it for high-speed transfer of any effective area signal And a control means for outputting a control signal to the drive pulse generating means, and output from the drive pulse generating means by a control signal from the control means at the time of reading the idle feed area signal or the vertical optical black area signal. According to a drive pulse, video signal processing is configured to perform correction processing on the fixed pattern noise by a correction signal generated by the correction signal generation means based on a video signal output from the solid-state imaging device apparatus.

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