N-colorant gamut construction
AssigneeKodak Graphic Communications Canada Company
InventorHarold Boll
Life of this patent
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Abstract
A method and system for constructing a color gamut allows the determination of the boundaries of the color gamut in color space for a color reproduction system having N-colorants. A forward model characterizing the color reproduction system is established and used to map a plurality of inkvectors from colorant space into color space. The color gamut is constructed by determining which of the mapped inkvectors define the boundaries of the color gamut in color space.
Claims20
A method for constructing a color gamut for a plurality of colorants used in a color image reproduction system, comprising the steps of:
- establishing a forward model for the color image reproduction system, the forward model characterizing the correspondence between combinations of the plurality of colorants and resulting colors in a color space;
- generating a set of inkvectors defining combinations of colorants in colorant space wherein each inkvector comprises two colorants that are allowed to vary freely between their respective minimum and maximum values, the remaining colorants being fixed at one of a maximum or a minimum value;
- using the forward model for mapping an inkvector coordinate into a color space coordinate;
- generating a plurality of gamut contours for a plurality of lightness levels in the color space wherein generating a gamut contour for a lightness level comprises:
- identifying a subset of inkvectors for the lightness level wherein the lightness range for each inkvector of the subset includes the lightness level;
- identifying a pair of endpoint coordinates in the color space for each inkvector of the subset of inkvectors for the lightness level wherein the pair of endpoint coordinates for an inkvector correspond to endpoints of a line formed by the intersection of the inkvector plane mapped to the color space and a lightness plane of the color space corresponding to the lightness level;
- identifying boundary coordinates from amongst the endpoint coordinates for the subset of the inkvectors;
- and
- forming the gamut contour for the lightness level by connecting the boundary coordinates.
A computer program product for constructing a color gamut for a plurality of colorants used in a color image reproduction system, the computer program product comprising a computer readable storage medium having a computer program stored thereon for performing the steps of:
- establishing a forward model for the color image reproduction system, the forward model characterizing the correspondence between combinations of the plurality of colorants and resulting colors in color space;
- generating a set of inkvectors defining combinations of colorants in colorant space wherein each inkvector comprises two colorants that are allowed to vary freely between their respective minimum and maximum values, the remaining colorants being fixed at one of a maximum or a minimum value;
- using the forward model for mapping an inkvector coordinate into a color space coordinate;
- generating a plurality of gamut contours for a plurality of lightness levels in the color space wherein generating a gamut contour for a lightness level comprises:
- identifying a subset of inkvectors for the lightness level wherein the lightness range for each inkvector of the subset includes the lightness level;
- identifying a pair of endpoint coordinates in the color space for each inkvector of the subset of inkvectors for the lightness level wherein the pair of endpoint coordinates for an inkvector correspond to endpoints of a line formed by the intersection of the inkvector plane mapped to the color space and a lightness plane of the color space corresponding to the lightness level;
- identifying boundary coordinates from amongst the endpoint coordinates for the subset of the inkvectors;
- and
- forming the gamut contour for the lightness level by connecting the boundary coordinates.
Dependencies are inferred from the claim text.