Patent ID: 8023765

Claim:
A block noise removal device for removing block noise from within a decoded video signal obtained by encoding and decoding an input video signal for each pixel block having a plurality of pixels, the block noise removal device comprising: an interpixel differential value calculator for calculating, as an interpixel differential value, a differential value between each two adjacent pixels in a frame of the decoded video signal; an accumulation unit for classifying, into separate pixel groups, the interpixel differential values by using a block size N (where N is an integer) of the decoded video signal or by using M which is an integer multiple of the block size N, and accumulating the interpixel differential values of the pixels disposed in the respective nth position (where n is 1 to N or 1 to M) in the respective pixel groups, thereby obtaining first to Nth block noise values or first to Mth block noise values; a block boundary detector for detecting the largest block noise value among the first to Nth block noise values or the first to Mth block noise values to generate a block boundary position signal that represents the pixel position having the largest block noise value in the pixel group, and detecting, as a phase error block noise value, the larger of the block noise values of the adjacent pixels on both sides of the pixel having the largest block noise value, so as to generate a phase error signal on the basis of a ratio between the phase error block noise value and the largest block noise value; a phase correction unit for obtaining a phase correction pixel sample value that is produced by performing phase correction processing based on the phase error signal on the decoded video signal; and a signal output unit for generating a noise-removed video signal by performing block noise removal processing on the basis of the phase correction pixel sample value.