Patent ID: 7158670

Claim:
A method for providing a color space representation of color images in a color management system, comprising the steps of: mapping RGB color data values representing an image in a first device into gamut expanded sRGB color data values of a gamut expanded sRGB color space; and converting the gamut expanded sRGB color data values of the gamut expanded sRGB color space into RGB color data values representing an image in a second device, the RGB color data values of the first device being different from the RGB color data values of the second device and the physical appearance of the image in the first device being the same as the physical appearance of the image in the second device, wherein the step of mapping includes utilizing multiplication of R 0 , G 0 , B 0 values by a predetermined matrix, where the R 0 , G 0 , and B 0 values denote normalized numerically linear red, green and blue components for a color value, wherein XYZ values are obtained in accordance with the following: ( X Y Z 1 ) = M - 1 ⁡ ( R 0 G 0 B 0 1 ) , where ⁢ ⁢ M - 1 = [ n XR n XG n XB u X n YR n YG n YB u Y n ZR n ZG n ZB u Z 0 0 0 1 ] , wherein X, Y, and Z denote 1931 Commission Internationale de l'Eclairage XYZ values where Y has been normalized to 1, wherein the XYZ values with respect to the D 65 standard are obtained in accordance with the following: { X D65 = x D65 / y D65 = 0.9502 Y D65 = 1.0 Z D65 = ( 1.0 - x D65 - y D65 ) / y D65 = 1.0887 , wherein a transformation matrix from XYZ to the gamut expanded sRGB color data values of the gamut expanded sRGB color space is obtained in accordance with the following: M w = M D65 ⁢ S w , where ⁢ ⁢ M D65 = [ 3.2410 - 1.5374 - 0.4986 0 - 0.9692 1.8760 0.0416 0 0.0556 - 0.2040 1.0570 0 0 0 0 1 ] ⁢ ⁢ and , ⁢ ⁢ where ⁢ ⁢ S w = [ X D65 / X w 0 0 0 0 1 0 0 0 0 Z D65 / Z w 0 0 0 0 1 ] , wherein the step of converting includes converting from the gamut expanded sRGB color data values of the gamut expanded sRGB color space to XYZ values based upon a transverse matrix obtained in accordance with the following: M w - 1 = S w - 1 ⁢ M D65 - 1 , where ⁢ ⁢ M D65 - 1 = [ 0.4124 0.3576 0.1805 0 0.2126 0.7152 0.0722 0 0.0193 0.1192 0.9505 0 0 0 0 1 ] ⁢ ⁢ and , ⁢ where ⁢ ⁢ S w - 1 = [ X w / X D65 0 0 0 0 1 0 0 0 0 Z w / Z D65 0 0 0 0 1 ] , wherein X w and Z w denote corresponding X and Z values with respect to a standard illuminant defined by CIE, wherein the RGB color data values representing the image in the second device are obtained in accordance with the following: ( R 0 G 0 B 0 1 ) = M ⁡ ( X Y Z 1 ) , where ⁢ ⁢ M = [ m RX m RY m RZ t R m GX m GY m GZ t G m BX m BY m BZ t B 0 0 0 1 ] , wherein m denotes a rotational part, t denotes a transitional part, n denotes an inverse rotational part, and u denotes an inverse transitional part.