Gamut Mapping Systems and Methods

摘要

Novel methods and systems for image processing and gamut mapping are disclosed, where image parameters in a first color space are transformed into parameters in a second color space. In one example, the gamut mapping system processes the image parameters in a parametrized space using substantially rectangular spectral functions. In another example, the gamut mapping system processes the image parameters in a parametrized space using smooth spectral functions. The smooth spectral functions may include a linear combination of functions, including at least a cosine square function. Image parameters may include an intensity parameter, a center wavelength parameter, and a saturation parameter.

主权项

1. Method for color conversion of an input image defined in a first color space into a target image defined in a second color space for display on a display device, the method comprising
receiving image parameters in the first color space, the image parameters defining the input image (405); converting the received image parameters defined in the first color space into spectral parameters defined in a spectral color space, wherein the spectral color space is a color space with a substantially rectangular representation of colors, the substantially rectangular representation using substantially rectangular functions of wavelength, or a smooth spectral representation of colors, the smooth spectral representation using smooth functions of wavelength; wherein each substantially rectangular function or smooth function is defined by the value of an intensity parameter (I), the value of a central wavelength λc parameter and the value of a saturation parameter (r), the saturation parameter (r) relating to the width of the respective substantially rectangular function or smooth function; and wherein the spectral parameters in the spectral color space are based at least in part on the intensity parameter (I), the central wavelength λc parameter and the saturation parameter (r); calculating a gamut ratio (Q) for at least one pixel for at least one of the intensity parameter and the saturation parameter, the gamut ratio (Q) for a given parameter and a given pixel indicating a ratio of the value of the given parameter for the given pixel and a value of the given parameter at a gamut boundary; comparing the at least one calculated gamut ratio (Q) with a threshold value to determine whether the color of the pixel under consideration is outside or inside the gamut boundary; when a pixel is outside the gamut boundary, transforming any of the intensity parameter (I), the central wavelength (λc) and the saturation parameter (r) to bring the parameter inside of the gamut boundary; converting the intensity parameter (I), the central wavelength (λc) and the saturation parameter (r) into image parameters defined in the second color space.