Patent ID: 6897876
Filing Date: 2005-05-24
Classification: G09G

Abstract:
1. A method for transforming three color input signals (R, G, B) corresponding to three gamut defining color primaries to four color output signals (R′, G′, B′, W) corresponding to the gamut defining color primaries and one additional color primary W for driving a display having a white point different from W, comprising: a) normalizing the color input signals (R,G,B) such that a combination of equal amounts in each signal produces a color having XYZ tristimulus values identical to those of the additional color primary to produce normalized color signals (Rn,Gn,Bn); b) calculating a common signal S that is a function F1 of the three normalized color signals (Rn,Gn,Bn); c) calculating a function F2 of the common signal S and adding it to each of the three normalized color signals (Rn,Gn,Bn) to provide three color signals (Rn′,Gn′,Bn′); d) normalizing the three color signals (Rn′,Gn′,Bn′) such that a combination of equal amounts in each signal produces a color having XYZ tristimulus values identical to those of the display white point to produce three of the four color output signals (R′,G′,B′); and e) calculating a function F3 of the common signal S and assigning it to the fourth color output signal W.