NOISE REDUCTION APPARATUS

摘要

A field recursive type noise reduction apparatus is disclosed in which the field difference is divided into a plurality of frequency components by means of the Hadamard transformation (7) and the existence of a boundary of oblique line in the proximity of pixels to be processed is detected from frequency components remaining by removing minimum and maximum horizontal frequency components by an oblique line detection circuit (21). In the location where the existence of the boundary of oblique line is detected, a feedback rate of the apparatus is reduced to avoid deterioration of the image quality by nonlinear processing means (22) and in other locations the feedback rate is increased to improve the S/N, so that there is realized the noise reduction apparatus having excellent effect in improvement of the S/N as compared with a conventional field recursive type noise reduction apparatus.