New algorithm for under color removal (UCR) using direct color ma

摘要

Abstract: Color transformation from RGB to CMYK is a significant problem in color reproduction. Since black ink is a redundant component, it is impossible to find a unique set of CMYK ink quantity suitable for an input RGB color. This paper proposes an algorithm for UAR, using the direct color mapping method from RGB to CMYK. It directly searches a measured gamut space for a printer for more than one set of CMYK ink quantities suitable for an input color with out using a reproduction model or a nonlinear equation. A set of CMYK ink quantity, suitable for an input color, is flexibly calculated from several sets of CMYK ink quantity by using interpolation controlled by an adjusting coefficient of black ink quantity. The flexible computation of black ink quantity makes it possible to adjust a delicate image appearance. This algorithm can be applied to various kinds of printers, because it does not require a model of the printer's color reproduction mechanism.!4