Patent ID: 6366291
Filing Date: 2002-04-02
Classification: G09G

Abstract:
A method of converting colorimetric values representing a composite color into display signals that are to be input into a target color display device to reproduce the composite color, the display signals being related to mixing quantities of device primary colors in a color mixture, the device primary colors being single-color components reproduced by respective single-color elements of the target color display device, the composite color being reproduced by the target color display device as a mixture of the device primary colors mixed in quantities according to the display signals, the target color display device having a reproducible range of the mixing quantity for each of the device primary colors, the method comprising:(a) defining a definition range of intensities of the display signals which are to be converted in the target color display device to the mixing quantities of the device primary colors within the reproducible range, the definition range being divided into a first conversion range and a second conversion range; (b) converting the colorimetric values for the composite color into the mixing quantities of the device primary colors according to a first conversion relation; and (c) converting the mixing quantities of the device primary colors into the intensities of the display signals according to a second conversion relation, comprising: (i) determining a defined relievable range for at least one selected device primary color among the device primary colors as a function of the mixing quantities of the remaining device primary colors other than the selected device primary color, the relievable range being out of and adjacent to the reproducible range and within a predetermined maximum relievable range; wherein (ii) when the mixing quantity of the selected device primary color is within the reproducible range, converting the mixing quantity of the selected device primary color into the intensity of the display signal within the first conversion range; and (iii) when the mixing quantity of the selected device primary color is within the relievable range, converting the mixing quantity of the selected device primary color into the intensity of the display signal within the second conversion range; wherein: the relievable range is determined so that an extent of the relievable range increases as the mixing quantities of the remaining device primary colors increases; and a ratio of the second conversion range to the definition range is smaller than a ratio of the reproducible range to the maximum relievable range.