Patent ID: 6421142
Filing Date: 2002-07-16
Classification: H04N

Abstract:
A method for deriving color space transformations for a color image reproduction system comprising an input device and an output device, wherein said output device has an output-device gamut including colors capable of being rendered by said output device, said method comprising:obtaining a first transformation for said input device that maps from colors within an input-device-dependent color space to colors within a first device-independent color space, wherein said first transformation is obtained by a process comprising: generating coordinate values for points in said input-device-dependent color space by scanning a medium conveying a plurality of first areas having different first color characteristics, obtaining coordinate values for points in said first device-independent color space representing said first color characteristics, defining a first initial transformation that maps from points in said first device-independent color space to corresponding points in said input-device-dependent color space, and deriving said first transformation from said first initial transformation such that, for a color within said output-device gamut, said first transformation is defined by interpolation of point values within said first device-independent color space, and for a first color outside of said output-device gamut, said first transformation is defined by a point in said first device-independent color space that corresponds to an intersection of a boundary of said output-device gamut with a projection between a point representing the first color and a point on a neutral-color line, such that the hue of the first color is preserved and the distance between the first color and the intersection of the boundary and the projection is minimized.