| 摘要 |
PURPOSE:To remove flicker noise by changing over plural integrating elements in a prescribed series order by synchronizing with a vertical synchronizing signal and selecting and cyclically repeating the change over and the selection of the prescribed series order by the beat frequency of the frequency of the vertical synchronizing signal and the flicker frequency of illuminated light. CONSTITUTION:Reflected light flux from an object 1 forms an image by a lens 2, is made incident on the photoelectric transfer surface of an image pickup element 3 and the photoelectric transfer output of the image pickup element 3 is inputted to an AGC circuit 4. The AGC circuit 4 operates so as to make the level of a video signal (luminance signal and chrominance signal) remain constant irrespetive of the level change of the output of the image pickup element 3. The output of the AGC circuit 4 is integrated by an integrator 5, fed back to the AGC circuit 4 and the amplifier gain of the AGC circuit 4 is controlled. Thereby, the flicker noise of the beat frequency included in a gain control means is cancelled.
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