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AssigneeHewlett-Packard Company
InventorsFrancis E. Bockman, Paul H. Dillinger
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A technique of merging or "matching" hue pages of a CRT and printer is used to map CRT control signals through a common perceptual space into printer control signals. The system (1) receives a color specification expressed as CRT control signals, (2) locates the specified color within the CRT perceptual gamut, (3) normalizes the two gamuts in perceptual space, (4) determines the relative position of the same color in the normalized CRT gamut, (5) declares that position to be the relative position of that color in the normalized printer gamut as well, (6) unfolds the normalization to determine the absolute position of the color in the actual printer gamut, (7) expresses that position in terms of printer-control signals, and then (8) applies those signals to the printer, to print the specified color. As a result that color, and color changes, specified in terms of CRT control signals are tracked in terms of both printer control signals and actual printer performance. The two device gamuts are in effect mapped to each other; the full gamuts of both are in effect merged. This new mapping preserves relative positions in color space--and thus the capability of the printer to reproduce distinctions between colors seen on the CRT that appear very closely similar. Such discrimination between colors very adjacent in color space is supported nearly throughout gamuts of both devices, even very near the lightness extrema and maximum-saturation point on a hue page. To facilitate processing, the normalized characterizations for the CRT and printer gamuts (taken as triangular) are approximated for each of 360 hue pages by single-point data representing lightness and chroma at the saturation point--or normalized lightness at that point--plus two common lightness extrema for the gamut solid.
A method for printing, with a color printer that has an at least partly known color gamut, a color image portion based on initial color specifications for use in a display device that has an at least partly known color gamut;
A method for printing, with a color printer that has an at least partly known color gamut, a color image composed of plural image portions and based on initial color specifications for use in a display device that has an at least partly known color gamut;
A set of lookup tables for use in printing, with a color printer that has an at least partly known color hue page that is part of the printer gamut, a color image based on input color specifications for use in a display device that has an at least partly known color hue page that is part of the display-device gamut:
A method for printing, with a color printer that has an at least partly known color hue page that is part of the printer gamut, a color image composed of plural image portions and based on color specifications for use in a display device that has an at least partly known color hue page that is part of the display-device gamut;
Dependencies are inferred from the claim text.