Data conversion table changing
First Claim
1. A method of converting color component data, comprising the steps of:
- (a) providing a data conversion table that converts color component data of a first color system to converted color component data for at least one color component of a second color system;
(b) changing first values of converted color component data in said data conversion table for a specific combination of color component data of said first color system, thereby obtaining first changed values;
(c) changing second values of converted color component data in said data conversion table for other combinations of color component data of said first color system other than said specific combination; and
(d) converting, with said data conversion table, the color component data of said first color system to the converted color component data of said second color system; and
whereinsaid step (c) comprises the steps of;
(1) determining differences between said first values and said first changed values;
(2) determining non-subject combinations of color component data of said first color system for which values of converted color component data are not to be changed;
(3) assuming an equation representing spatial distribution of differences to be used in said changing said second values for said other combinations in a color space of said first color system; and
(4) solving said equation to determine said differences to be used in said changing said second values for said other combinations other than said specific combination, under conditions that the differences for said specific combination are equal to the differences determined at step (1) and that the differences for said non-subject combinations are equal to zero.
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Abstract
In a three-dimensional LUT for color conversion, the values of converted color component data C'"'"', M'"'"', and Y'"'"' are varied for a specific combination of the values of color component data C, M, and Y representing white, and the values of converted data are then changed for other combinations accompanied by the variation with respect to the specific combination. Referring to FIG. 1B, a concrete procedure first calculates variations of the values of color component data C'"'"', M'"'"', and Y'"'"' at step S20, and then selects combinations of the values of color component data C, M, and Y for which the values of color component data C'"'"', M'"'"', and Y'"'"' are not changed, among a plurality of combinations of the values of color component data C, M, and Y at step S22. For colors between white and cyan, magenta, yellow or black, the variations of the values of color component data C'"'"', M'"'"', and Y'"'"' are set to decrease in an increase in distance from a point corresponding to white in a three-dimensional color space at step S24. The procedure then leads Laplace'"'"'s Equation including the variations and the values of color component data C, M, and Y as variables at step S26, and solves the Laplace'"'"'s Equation to determine the variations of the values of color component data C'"'"', M'"'"', and Y'"'"' for each combination of the values of color component data C, M, and Y at step S28. This procedure enables the contents of the three-dimensional LUT for color conversion to be changed readily within a short time.
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Citations
38 Claims
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1. A method of converting color component data, comprising the steps of:
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(a) providing a data conversion table that converts color component data of a first color system to converted color component data for at least one color component of a second color system; (b) changing first values of converted color component data in said data conversion table for a specific combination of color component data of said first color system, thereby obtaining first changed values; (c) changing second values of converted color component data in said data conversion table for other combinations of color component data of said first color system other than said specific combination; and (d) converting, with said data conversion table, the color component data of said first color system to the converted color component data of said second color system; and
whereinsaid step (c) comprises the steps of; (1) determining differences between said first values and said first changed values; (2) determining non-subject combinations of color component data of said first color system for which values of converted color component data are not to be changed; (3) assuming an equation representing spatial distribution of differences to be used in said changing said second values for said other combinations in a color space of said first color system; and (4) solving said equation to determine said differences to be used in said changing said second values for said other combinations other than said specific combination, under conditions that the differences for said specific combination are equal to the differences determined at step (1) and that the differences for said non-subject combinations are equal to zero. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38)
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Specification