Color conversion method
First Claim
1. A method of displaying colour images, intended to be displayed on a first colour display device, on a second colour display device having a colour gamut different from the first colour display device, said method including the steps of:
- (a) determining a plurality of input extrema colour values, within the colour gamut of said first colour display device and at the extrema of the gamut of said first colour display;
(b) determining a plurality of output extrema colour values corresponding to said input extreme colour values, within the colour gamut of said second colour display and at the extrema of the gamut of said second colour display; and
(c) determining a mapping for substantially all the values within the colour gamut of the first colour display to substantially all the values within the gamut of the second colour display, said mapping substantially preserving the relative value of differences between colour values relative to the extent of the gamut of said first colour space and differences between corresponding colour values in the gamut of said second colour space relative to the extent of the gamut of said second colour space;
wherein said mapping includes determining a colour correction function mapping colour gamut values within the gamut of said second colour display to colour gamut values within the colour gamut of said first colour display, and said colour correction function includes a number of free parameters, the values of which are determined by measurement of output colour values of said second colour display device.
1 Assignment
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Accused Products
Abstract
A method of displaying color images, intended to be displayed on a first color display device, on a second color display device having a color gamut (2) different from a color gamut (1) of the first color display device. The method includes a first step of determining a plurality of input extrema color values (RGB), within the color gamut (1) of the first color display device and at the extrema of the gamut of the first color display. Next, the method determines a plurality of output extrema color values (R'"'"'G'"'"'B'"'"') corresponding to the input extrema color values (RGB), within the color gamut (2) of the second color display and at the extrema of the gamut (2) of the second color display. Then, the method determines a mapping for substantially all the values within the color gamut (1) of the first color display to substantially all the values within the gamut (2) of the second color display, the mapping substantially preserving the relative value of differences between color values relative to the extent of the gamut (1) of the first color space and differences between corresponding color values in the gamut (2) of the second color space relative to the extent of the gamut (2) of the second color space.
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Citations
22 Claims
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1. A method of displaying colour images, intended to be displayed on a first colour display device, on a second colour display device having a colour gamut different from the first colour display device, said method including the steps of:
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(a) determining a plurality of input extrema colour values, within the colour gamut of said first colour display device and at the extrema of the gamut of said first colour display; (b) determining a plurality of output extrema colour values corresponding to said input extreme colour values, within the colour gamut of said second colour display and at the extrema of the gamut of said second colour display; and (c) determining a mapping for substantially all the values within the colour gamut of the first colour display to substantially all the values within the gamut of the second colour display, said mapping substantially preserving the relative value of differences between colour values relative to the extent of the gamut of said first colour space and differences between corresponding colour values in the gamut of said second colour space relative to the extent of the gamut of said second colour space; wherein said mapping includes determining a colour correction function mapping colour gamut values within the gamut of said second colour display to colour gamut values within the colour gamut of said first colour display, and said colour correction function includes a number of free parameters, the values of which are determined by measurement of output colour values of said second colour display device. - View Dependent Claims (2, 3, 4, 5)
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6. A method of displaying colour images, intended to be displayed on a first colour display device, on a second colour display device having a colour gamut different from the first colour display device, said method including the steps of:
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(a) determining a plurality of input extrema colour values, within the colour gamut of said first colour display device and at the extrema of the gamut of said first colour display; (b) determining a plurality of output extrema colour values corresponding to said input extrema colour values, within the colour gamut of said second colour display and at the extrema of the gamut of said second colour display; and (c) determining a mapping for substantially all the values within the colour gamut of the first colour display to substantially all the values within the gamut of the second colour display, said mapping substantially preserving the relative value of differences between colour values relative to the extent of the gamut of said first colour space and differences between corresponding colour values in the gamut of said second colour space relative to the extent of the gamut of said second colour space, wherein said mapping includes determining a colour correction function mapping colour gamut values within the gamut of said second colour display to colour gamut values within the colour gamut of said first colour display device, and wherein said colour correction function is substantially of the form;
space="preserve" listing-type="equation">I=-1n(1-(1-e.sup.-G)C)/Gwhere C is a colour value within the colour gamut of said second colour display, G is a predetermined value or a predetermined function, and I is the corresponding colour within the gamut of said first colour display device. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
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14. A method of displaying colour images, intended to be displayed on a first colour display device, on a second colour display device having a colour gamut different from the first colour device, and of correcting any distortion caused by the display of the images on the second colour device, said method including the steps of:
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(a) defining a colour correction function, wherein the colour correction function is representative of an inverse of the distortion and has a number of unknown free input parameters; (b) measuring a plurality of output colour values of said second colour display device corresponding to a plurality of input colour values; and (c) determining the unknown free input parameters of the colour correction function by utilizing the measured output colour values of the second display device and the corresponding input color values. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
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Specification