METHOD FOR COMPENSATING COLOR DIFFERENCE SIGNAL CHANGE IN MOVING IMAGE, MOVING IMAGE CODER AND MOVING IMAGE DECODER

摘要

PROBLEM TO BE SOLVED: To obtain a coded image with high image quality regardless of a small arithmetic amount and a small data amount. ;SOLUTION: A luminance change detection section 5 calculates parameters DC(i), DB(i) denoting changes in a luminance signal in a block B₁. A frequency calculation section 6 obtained the frequency of the parameters DC(i), DB(i) by one frame and decides a set of the parameters with a highest frequency as parameters α, β denoting a global luminance change in an original image of an N-th frame. A luminance change compensation section 7 applies luminance change compensation to a luminance value Y of a reproduced image of an (N-1)th frame according to an equation of Y'=α.Y+β. Furthermore, a color difference change compensation section 10 applies color difference change compensation to each of color difference values CB, CR of the reproduced image of the (N-1)th frame according to equations C'B=α.CB and C'R='.CR respectively.;COPYRIGHT: (C)1998,JPO