DECODER HAVING ADAPTIVE BLOCK PHENOMENON REMOVING FUNCTION AND METHOD FOR REMOVING/DECODING ADAPTIVE BLOCK PHENOMENON

摘要

PROBLEM TO BE SOLVED: To acquire an image of fine picture quality by adaptively estimating a spatial frequency component in accordance with a result whether a current block exists on the boundary of an object or not. ;SOLUTION: A block phenomenon judge 77 determines whether spatial frequency can be estimated or not by adding the number of nonzero spatial frequency components from an output signal of an inverse quantizer, and a boundary detector 78 constitutes a DC image not in a pixel area but in a spatial frequency area. Since the DC value in the spatial frequency area corresponds to eight times the mean value of a 8 *8 blocks in the pixel area, the detector 78 determines the boundary by dividing the DC value by 9 and obtaining the mean value of 8 * 8 blocks. An adaptive spatial frequency component estimator 79 estimates a spatial frequency component based on an output signal from the detector 78 when a current block does not exist near the boundary, and wen the current block exists on the boundary of an object or on a position exerting influence upon the boundary, substitutes the DC value of the current block for the DC value of the block existing on the position exerting influence upon the boundary in a changed format and estimates the spatial frequency component.;COPYRIGHT: (C)1999,JPO