Patent ID: 7184174

Claim:
A color picture signal processing method, comprising the steps of: (a) inputting picture signal data of primary colors or complementary colors; (b) converting said picture signal data to data of luminance Y and data of color differences Cr and Cb on a Y-Cr-Cb space; and (c) executing a color difference matrix calculation by using at least one pair of equations (i) to (iv), wherein Cr′=Cr×A/K+C×B, Cb′=Cr×C+Cb×D ( i ), Cr ′=( Cr×A+Cb×B ) /K, Cb′=Cr×C+Cb×D ( ii ), Cr′=Cr×A+Cb×B, Cb′=Cr×C+Cb×D×K (iii), and Cr′=Cr×A+Cb×B, Cb′= ( Cr×C+Cb×D ) ×K ( iv ), where A, B, C and D are color difference matrix coefficients, K is a function of Y and also a correction coefficient larger than 0, K is determined to fix a color difference ratio H (=Cr′/Cb′) regardless of the luminance Y, and Cr′ and Cb′ are color differences after correction.