Method for processing color image data

A display driver comprising circuitry for processing color image data to be displayed on a target device, the display driver comprising:

• a processor to receive input pixel data within a source color gamut, and map said input pixel data from said source color gamut to a target color gamut associated with said target device, the amount of mapping being adapted dynamically, at least partially according to a color saturation value of said input pixel data and a luminance value of said input pixel data, wherein the target color gamut has a limited size with respect to the source color gamut,
• the processor further configured for generating a scale parameter, a rotate parameter and a shift parameter at least partially according to the color saturation value and the luminance value, and performing the mapping at least partially according to the scale parameter, the rotate parameter, and the shift parameter;
• wherein the scale parameter is determined as a function of the color saturation value, and corrects for a saturation of the output pixel data;
• the rotate parameter is determined as a function of the color saturation value, and corrects for a hue and a white point of the output pixel data;
• and
• the shift parameter is determined as a function of the luminance value, and corrects for a white point of the output pixel data,
• wherein the processor is further configured to map the color saturation value and a hue value of said input pixel data;
• wherein the amount of the mapping of the color saturation value and the hue value is substantially uniform when the hue value is less than a first threshold, and generally linearly decreases when the hue value is greater than the first threshold;
• and
• wherein the first threshold is a hue value corresponding to a point closest to the target display white point on one side of a target display color triangle.

A non-transitory computer readable storage medium comprising a computer program including a set of instructions executable by a processor, the medium comprising:

• code for receiving input pixel data within a source color gamut, and
• code for mapping of said input pixel data from said source color gamut to a target color gamut associated with said target device, the amount of mapping being adapted dynamically, at least partially according to a color saturation value of said input pixel data and a luminance value of said input pixel data, wherein the target color gamut has a limited size with respect to the source color gamut,
• code for generating a scale parameter, a rotate parameter and a shift parameter at least partially according to the color saturation value and the luminance value, and performing the mapping at least partially according to the scale parameter, the rotate parameter, and the shift parameter, wherein
• the scale parameter is determined as a function of the color saturation value, and corrects for a saturation of the output pixel data;
• the rotate parameter is determined as a function of the color saturation value, and corrects for a hue and a white point of the output pixel data;
• and
• the shift parameter is determined as a function of the luminance value, and corrects for a white point of the output pixel data:
• wherein the mapping further comprises mapping the color saturation value and a hue value of said input pixel data;
• wherein the amount of the mapping of the color saturation value and the hue value is substantially uniform when the hue value is less than a first threshold, and generally linearly decreases when the hue value is greater than the first threshold;
• and
• wherein the first threshold is a hue value corresponding to a point closest to the target display white point on one side of a target display color triangle.