| 摘要 |
PURPOSE:To extract noise components of an amplitude level in response to the level of an input video signal by varying the nonlinear processing characteristic of a nonlinear processing circuit in response to the amplitude level of the input video signal. CONSTITUTION:An input video signal 100 is inputted to subtraction circuits 2, 4 and a level detecting circuit 1. The subtracting circuit 2 subtracts a delayed video signal 300 subject to delay in one frame time read from a frame memory 5 and outputs a frame difference signal 400 to a nonlinear processing circuit 3. On the other hand, the level detecting circuit 1 detects the level of the input video signal by comparing it with a preset level and outputs a control signal in response to the level to the nonlinear processing circuit 3. The nonlinear processing circuit 3 changes the nonlinear processing characteristic in response to the control signal, extracts noise component 500 from a frame difference signal 400 and supplies it to the subtracting circuit 4.
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