Patent ID: 6388674
Filing Date: 2002-05-14
Classification: G09G,H04N

Abstract:
A color mapping method of changing a color, when an output color gamut is different from an input color gamut, the input color gamut to the output color gamut, comprising:correcting the color using a predetermined function for a difference in the lightness-directional dynamic range, and correcting the color by a combination of a three-dimensional compression of lightness, chroma and hue and a two-dimensional shrinkage or expansion of the lightness and chroma, wherein correcting the color further includes: dividing the input gamut by four with a first straight line passing through a minimum value point L*min of the lightness L* in the output gamut and a second straight line passing through a maximum value point L*max of the lightness L* in the output gamut, these first and second straight lines intersecting each other at a point (C*th, L*_th) of the lightness value L*_th having a maximum chroma value C*_max of the output gamut in a two-dimensional plane of the lightness L* and chroma C* with the hue h kept constant, thereby defining an area A above the first straight line and below the second straight line, an input area B other than the area A and corresponding to the output color gamut, an input area C other than an area corresponding to the output color gamut, and an area D other than the output and input color gamuts; and leaving the color in the area A as it is and correcting the color by a combination of the three-dimensional compression and two-dimensional shrinkage or expansion.