Patent ID: 8116562

Claim:
A circuitry-implemented method for image processing, the method comprising: (1) obtaining digital data representing a V value for each of one or more image portions p 1 , p 2 , each V value representing a color property of the respective image portion, wherein each image portion p (p=p 1 , p 2 , . . . ) has a color S(p) having a coordinate S 1 in a first coordinate system, wherein for a color S having tristimulus values T 1 , T 2 , T 3 in a second coordinate system: (1A) the coordinate S 1 is defined by a B value B = g 11 ⁢ T 1 2 + g 22 ⁢ T 2 2 + g 33 ⁢ T 3 2 + g 12 ⁢ T 1 ⁢ T 2 + g 13 ⁢ T 1 ⁢ T 3 + g 23 ⁢ T 2 ⁢ T 3 wherein g 11 , g 22 , g 33 , g 12 , g 13 , g 23 are predefined constants, and g 11 , g 22 , g 33 are not equal to zero, or (1B) the coordinate S 1 is defined by the B value and by a sign of a predefined function of one or more of T 1 , T 2 , T 3 ; (2) processing the digital data to obtain the coordinate S 1 for each said image portion, wherein for each V value in a first range of values, the corresponding coordinate S 1 corresponds to the B value of: B=[b (V−k 4 )/k 1 −k 3 ]/k 2 wherein k 1 , k 2 , k 3 , k 4 , b are predefined constants, k 2 and k 3 are not zero, and b is positive and not equal to one.