Patent ID: 8103092

Claim:
A method for determining whether a given color is inside or outside a boundary surface of a color gamut of a color marking device, the method comprising: identifying a given point x c in L*a*b* space having {L c *, a c *, b c *} values; setting a threshold error value to a default value, said threshold error value being used for determining whether point x c is inside or outside a boundary surface of a color gamut of a color marking device; obtaining L*a*b* values using initial input N-color separation values for point x c , where N≧3; determining an amount of deltaE color separation between said L*a*b* values and said {L c *, a c *, b c *} values of point x c ; in response to said deltaE color separation being less than said threshold value, determining that point x c is inside said boundary surface of said color gamut; otherwise, repeating until a determination has been made whether point x c is inside or outside said boundary surface of said color gamut: generating new N-color values for point x c using a feedback controller; obtaining new L*a*b* output values using said new N-color values as inputs; determining an amount of deltaE color separation between said new L*a*b* output values and said {L c *, a c *, b c *} values of point x c ; comparing said deltaE color separation with said threshold error value, and in response to said deltaE color separation being less than said threshold error value, determining that x c is inside said boundary surface of said gamut; and otherwise, after a defined number of iterations, making a determination whether point x c is outside said boundary surface of said gamut; and in response to a determination that x c is outside said boundary surface of said color gamut, providing said {L c *, a c *, b c *} values to a gamut mapping function.