| 摘要 |
PURPOSE:To highly accurately control the level of a video signal by extracting the plural same picture element signals in a common object image and controlling the amplifying gain or the direct current offset level of plural video circuit devices. CONSTITUTION:The mutually corresponding plural picture element signals of video inputs Ain, Bin are extracted to calculate an average value and a distributed value in a control constant decision circuit 3 and the gain (q) and the direct current offset (r) as a signal level control constant and a white clip level (s) and a black clip level (t) are set. Then, the input Bin is multiplied by the gain (q) in a multiplier 1 and an adder 2, the direct current offset (r) is added to take out a video output (z) to be controlled and the video output (z) to be controlled and the reference video input Ain are clipped to the constant signal level of the picture element signal in the non-linear characteristic area of a white level side and a black level side in clip circuits 5, 4 to match to a signal level characteristic.
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