Apparatus and method of block noise detection and reduction

摘要

Block noises generated on an input video signal that has been coded and decoded per pixel block are detected. The input video signal is differentiated per pixel to obtain a differentiated signal. Impulses of the differentiated signal are detected to obtain a detection signal carrying the impulses. The detection signal is integrated and compared with a reference signal to determine whether the block noise is generated on the input video signal. For noise reduction, the detection signal is filtered to obtain a corrected signal. The input video signal is delayed by a predetermined period. The correction signal is added to the delayed video signal to cancel the difference in signal level on the boundary between a first pixel block on which a block noise is generated and a second block adjacent to the first pixel block of the input video signal.