PURPOSE:To simultaneously attain the satisfactory noise reduction effect and the suppression of afterimages by subtracting the output signal from the difference signal with a subtraction circuit and attenuating the component changing slowly out of the difference signal. CONSTITUTION:A noise component (e) given from a nonlinear circuit 6 is subtracted from an input video signal (a) with a subtraction circuit 2. Thus the signal (a) is outputted as a video signal (b). The signal (b) is delayed by the delay circuits 4a and 4b and supplied to a subtraction circuit 7. Then the output video signal (f) of the circuit 4b is subtracted from the signal (a) to produce a difference signal (g). The signal (g) is multiplied by a coefficient L with a coefficient device 9 (0L1) and supplied to a subtraction circuit 8 together with a difference signal (d). The circuit 8 subtracts the output signal (h) of the device 9 from the signal (d) and attenuates the component changing slowly out of the signal (d) to supply a difference signal (i) to the circuit 6. The circuit 6 has the transmission gain that keeps the signal (i) at a fixed level within an amplitude range set previously and reduces gradually the level of the signal (i) at the upper limit or above of the amplitude range. Then a signal (e) thus processed is supplied to the circuit 2 as a noise component.
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