JPS6447112A - Noise reducer - Google Patents

Abstract

PURPOSE:To reduce the noise in a picture signal with a broad band without picture quality deterioration by adding a low frequency picture signal whose noise is reduced by a 1st arithmetic circuit and a delay circuit to a high frequency picture signal by a 2nd arithmetic circuit so as to use a memory of a low capacity. CONSTITUTION:The low frequency component of an input picture signal is separated by an LPF 8 and fed to the 1st and 2nd arithmetic circuits 2, 1. The low frequency signal is multiplied by [1-K] at a coefficient, multiplication circuit 9 and the result is fed to a delay circuit 5. A control circuit 13 stores the signal into a memory 12, reads a signal before a prescribed time and the signal is multiplied by K at a coefficient multiplication circuit 11 and the result is fed to an adder circuit 10. The circuit 10 adds two signals and gives a low frequency signal whose noise is reduced to the circuit 1. An adder circuit 3 gives an added signal between the high frequency signal fed from a subtracter circuit 7 and the low frequency signal whose noise is reduced as the sum signal. Thus, the increase in the memory capacity is suppressed, the deterioration in the picture is avoided and efficient noise reduction is attained.