NOISE REDUCER

In a noise reducer, a first subtractor 101 generates a difference N1 between an input video signal Ynow and a delayed video signal Ypre output from a frame memory 104 and obtained by delaying an output video signal Yout by a time corresponding to one screen. An amplitude adjuster 102 adjusts the amplitude of an output signal of the first subtractor 101 based on a motion signal MV. A second subtractor 103 subtracts an output N2 of the amplitude adjuster 102 from the input video signal Ynow. A motion detector 2 calculates the amount of change in the input video signal Ynow with respect to the delayed video signal Ypre for each of pixels constituting one screen, and generates, as the motion signal MV, a signal determining, as "moving," a predetermined proportion of pixels for which the amount of change is smaller than a predetermined threshold value.