Color gamut mapping

Apparatus, comprising:

• a computer-readable medium storing computer-readable instructions;
• and
• a data processing unit coupled to the memory, operable to execute the instructions, and based at least in part on the execution of the instructions operable to perform operations comprising
• for each of multiple pixels of an image, transforming values of input color components of the pixel in an input device-dependent color space to values of output color components in an output device-dependent color space characterized by an output color gamut defined by a respective gamut range for each of the output color components,
• wherein the transforming comprises multiplying the input color component values of the pixel with corresponding elements of a device-dependent characterization matrix to produce a set of product values, deriving the output color component values from the product values, and the determining comprises ascertaining the values of a particular one of the output color components based on a continuous nonlinear companding function that maps a function input value derived from one or more of the product values to a function output value that increases monotonically with increasing function input values over the respective gamut range of the particular output color component.