Patent ID: 8300069

Claim:
A method of calculating a first backlight driving level and a second backlight driving level, for a color display for displaying pictures with a color gamut spanned by a number of color primaries having a backlight, the method comprising the acts of: controlling the backlight to produce a first amount of light with a first backlight spectrum in accordance with the first backlight driving level and a second amount of light with a second backlight spectrum in accordance with the second backlight driving level; outputting a first color primary light output and a second color primary light output by the color display having a first light transmission valve and a second light transmission valve plus a color filter combination formed from the first backlight spectrum and the second backlight spectrum, respectively, wherein a chromaticity of at least one of the color primaries depends on the first backlight driving level and the second backlight driving level; determining an input picture color gamut of at least a part of a picture to be displayed; scaling the determined input picture color gamut to form a scaled picture color gamut by changing valve drive levels of the first light transmission valve and the second light transmission valve, wherein a desired color is outside the scaled picture color gamut; determining the first backlight driving level and the second backlight driving level for matching a color gamut realizable by the color display with the first backlight driving level and the second backlight driving level to the determined input picture color gamut; and transforming the scaled picture color gamut to a converted picture color gamut by driving the backlight with the determined first backlight driving level and the determined second backlight driving level, wherein the desired color is inside the transformed picture color gamut.