Patent ID: 6765586
Filing Date: 2004-07-20
Classification: H04N

Abstract:
A printing apparatus for transforming first color image data for use on a first image processing device, into second color image data for use in printing by referencing a color transformation lookup table, and thereby printing,wherein said color transformation lookup table has a first set of values and a second set of values which represent a relationship between color gamuts of the first image processing device and the second image processing device, and if there exists the region that is out of the color gamut of the first image processing device but fails within the color gamut of the second image processing device in a certain hue of a device-independent color space, said relationship is equivalent to the relationship of color gamut determined, based on gamut mapping in a predefined device-independent color space, through a process comprising: a color gamut shift step to obtain the mapping which expands the shape of the color gamut of the first image processing device so as to be close to the shape of the color gamut of the second image processing device in a homogeneous hue range; and a color gamut expansion step to obtain the mapping which expands a certain region of the resulting gamut processed at said color gamut shift step into the inside of color gamut of the second image processing device.