Color processing system

A color processing system that receives from a first device an RGB color input signal and converts it into a CMYK color output of a second device, the system comprising:

• a color mapper that converts the RGB color input signal into standardized, perceptually uniform color information defined in a PQV color space, the color mapper utilizing tack point selection and generating corresponding conversion matrices, the tack point selection establishing a correspondence between the RGB color input signal and an output color designated in the PQV color space and entailing a selection of at least eight tack points that include primary colors, secondary colors, white and black, and the generating of corresponding conversion matrices entailing a generation of matrices for sectors of the PQV color space corresponding to a volume bounded by four tack points including the white tack point (W) and the black tack point (K), thereby forming a KWRY sector, a KWYG sector, a KWGC sector, a KWCB sector, a KWBM sector and a KWMR sector, where R, Y, G, M, C and B constitute respective red, yellow, green, magenta, cyan and blue tack points, and the generated conversion matrices corresponding to the KWRY, KWGC and KWBM sectors are similar in PQV color space and for the KWRY sector, comprise:
• ______________________________________ P.sub.r P.sub.y -P.sub.r P.sub.w -P.sub.y Q.sub.r Q.sub.y -Q.sub.r Q.sub.w -Q.sub.y V.sub.r V.sub.y -V.sub.r V.sub.w -V.sub.y ______________________________________
• and the RGB color input signal conversion into PQV color space information entails matrix multiplication of the RGB color input signal and the conversion matrix corresponding to the sector of the PQV color space in which the input signal is located;
• and
• a gamut mapper that converts the PQV color space information into a CMYK color output signal, the color output generated in accordance with the CMYK color output signal exhibiting enhanced color characteristics.

A color processing system that receives from a first device an input signal and converts it into a color output of a second device, the system comprising:

• a color mapper that converts a device-dependent input signal into standardized, perceptually uniform color information;
• and
• a gamut mapper that converts the perceptually uniform color information into a device-dependent output signal, the gamut mapper comprising hue mapping to convert an input hue signal into an output hue and chroma/value mapping to convert an input chroma/value signal to an output chroma/value, the hue mapping entailing hue circle partitioning to establish a correspondence between input hues and endpoints of hue circle portions designated in a perceptually uniform color space, identifying the hue circle portion in which an input hue is located, and applying a weighting function to determine an output hue corresponding to the input hue within the identified hue circle portion;
• whereby the color output generated in accordance with the device-dependent output signal exhibits enhanced color characteristics.

A color processing system for use with a Post-Script.RTM. Level 2 interpreter to convert an input signal from a first device into a color output of a second device, the system comprising:

• a user-selectable library of color rendering dictionaries including Blue Adjust, Simulate Video, or Simulate Press;
• a color mapper that converts the input signal into standardized, perceptually uniform color information;
• and
• a gamut mapper that converts the perceptually uniform color information into a device-dependent output signal,
• whereby the color mapper and the gamut mapper cooperate with the user-selected color rendering dictionary to provide the device-dependent color output signal such that the color output of the second device exhibits enhanced color characteristics closely matching the user's aesthetic expectations.