Block noise detector and block noise eliminator

摘要

A vertical HPF 11 and a horizontal HPF 12 receive a video signal 101, and extract only a high frequency component in the vertical/horizontal directions, respectively. Absolute value taking parts 13 and 14 take an absolute value thereof and change the value to a positive value. A horizontal accumulating/adding part 15 and a vertical accumulating/adding part 16 accumulate/add an input signal so as to output a vertical one-dimensional signal and a horizontal one-dimensional signal each periodically having a peak value in the vertical and horizontal directions. A horizontal peak detecting part 18 detects a horizontal peak position according to the horizontal one-dimensional signal. A vertical peak detecting part 17 detects a vertical peak position according to the vertical one-dimensional signal and identifies a format thereof. A binarization part 19 obtains a block boundary image, according to the horizontal peak position and the vertical peak position, in which pixel positions having a peak is provided with 1 and remaining pixel positions are provided with 0. In this manner, even if a block boundary to eliminate block noise thereon is not clearly identified, it becomes possible to correctly detect and eliminate the block boundary.