KR970068510A - Video signal processing circuit - Google Patents

Abstract

The present invention relates to a video signal processing circuit, comprising a sample-and-hold unit for sampling and holding an input video signal from a CCD and converting pixel information contained in the video signal into a smooth video signal waveform, An automatic gain control unit for adjusting the gain of a sample-held video signal output from the hold unit to automatically adjust the brightness of the image to an optimized state; and a gain control unit for correcting gradation characteristics of the CCD, A gamma correcting unit for making the automatically adjusted video signal have a linear characteristic and a gain control unit for enabling the video signal output from the gamma correction unit when the backlight is applied to the video signal, A filter section, a feedback section for giving a signal output from the filter section, a blank section for secure clamping, and a synchronization section when the signal is scanned And a video processor for outputting a video signal by doubling the gain so that the signal output from the sync-blank unit is impedance-matched with an external terminal. Therefore, it is possible to reduce the gain of the video signal in the backlight signal processing, thereby preventing the relative deterioration of the subject signal due to the white level of the backlight signal, and thus to restore the desired subject signal clearly.

Description

Video signal processing circuit

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Fig. 2 is a circuit diagram of a video signal processing circuit according to the present invention; Fig. 3 is a specific circuit of the filter section of Fig. 2; Fig.

Claims (2)

A sample-and-hold unit for sampling and holding an input video signal from the CCD to convert pixel information included in the video signal into a smooth video signal waveform, and a sample-and- An automatic gain control unit for adjusting the gain of the signal to automatically adjust the brightness of the image to an optimized state; and a gain control unit for adjusting the grayscale characteristic of the CCD so that the gain-controlled video signal input from the automatic gain control unit has a linear characteristic A filter unit for amplifying the image signal by -6 dB to reduce the gain to 1/2 when the image signal output from the gamma correction unit is backlighted, A blanking interval for secure clamping and a synchronizing interval for synchronizing when the signal is scanned, Portion, and the sink-video signal processing circuit including an image processor for outputting an image signal by the gain so that the impedance matching with an external terminal a signal outputted from the blank portion doubled. The apparatus of claim 1, wherein the filter unit comprises: a filter unit enabled when the video signal output from the gamma correction unit is enabled to amplify the video signal by -6bB to reduce the gain to 1/2; The first and second switching signals having different phases from each other according to different enable signals when there is no backlight in the video signal output from the gamma correction unit, A first switching signal for selecting a first path and outputting a video signal amplified by -6 dB in the amplifying means, a second path being selected by a second switching signal, and being output from the gamma adjusting unit And output means for outputting the video signal without amplifying the video signal. ※ Note: It is disclosed by the contents of the first application.