PURPOSE: To attain suitable picture correction on real time, by controlling a transfer function of a filter in response to the autocorrelation function of a picture signal to be corrected.

CONSTITUTION: Taking sampling values of an input signal s(t)*h(t) as s1∼ sn, an autocorrelation function ss(τ) of an original picture signal s(t) is described as Equation. Taking an autocorrelation function of a deteriorated input picture signal as 'ss(τ), the relation of 'ss(τ)=ss(τ)*hh is obtained, where *is convolution integration and hh is impulse response of a one-dimensional fog function. In obtaining the constant of a filter restoring the original picture s(t), a filter constant G(f) is changed to determine the constant so as to minimize absolute value 1/0, absolute value 2/0,∼absolute value 5/ 0.