Method for rendering color images
First Claim
Patent Images
1. A system for producing a color image, comprising:
- an electro-optic display having pixels and a color gamut including a palette of primaries; and
a processor in communication with the electro-optic display, the processor being configured to render color images for the electro-optic device by;
a. receiving first and second sets of input values representing colors of first and second pixels of an image to be displayed on the electro-optic display;
b. equating the first set of input values to a first modified set of input values;
c. projecting the first modified set of input value on to the color gamut to produce a first projected modified set of input values when the first modified set of input values produced in step b is outside the color gamut;
d. comparing the first modified set of input values from step b or the first projected modified set of input values from step c to a set of primary values corresponding to the primaries of the palette, selecting the set of primary values corresponding to the primary with the smallest error, thereby defining a first best primary value set, and outputting the first best primary value set as the color of the first pixel;
e. replacing the first best primary value set in the palette with the first modified set of input values from step b or the first projected modified set of input values from step c to produce a modified palette;
f. calculating a difference between the first modified set of input values from step b or the first projected modified set of input values from step c and the first best primary value set from step e to derive a first error value;
g. adding to the second set of input values the first error value to create a second modified set of input values;
h. projecting the second modified set of input value on to the color gamut to produce a second projected modified set of input values when the second modified set of input values produced in step g is outside the color gamut;
i. comparing the second modified set of input values from step g or the second projected modified set of input values from step h to the set of primary values corresponding to the primaries of the modified palette, selecting the set of primary values corresponding to the primary from the modified palette with the smallest error, thereby defining a second best primary value set, and outputting the second best primary value set as the color of the second pixel.
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Abstract
A system for rendering color images on an electro-optic display when the electro-optic display has a color gamut with a limited palette of primary colors, and/or the gamut is poorly structured (i.e., not a spheroid or obloid). The system uses an iterative process to identify the best color for a given pixel from a palette that is modified to diffuse the color error over the entire electro-optic display. The system additionally accounts for variations in color that are caused by cross-talk between nearby pixels.
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Citations
18 Claims
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1. A system for producing a color image, comprising:
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an electro-optic display having pixels and a color gamut including a palette of primaries; and a processor in communication with the electro-optic display, the processor being configured to render color images for the electro-optic device by; a. receiving first and second sets of input values representing colors of first and second pixels of an image to be displayed on the electro-optic display; b. equating the first set of input values to a first modified set of input values; c. projecting the first modified set of input value on to the color gamut to produce a first projected modified set of input values when the first modified set of input values produced in step b is outside the color gamut; d. comparing the first modified set of input values from step b or the first projected modified set of input values from step c to a set of primary values corresponding to the primaries of the palette, selecting the set of primary values corresponding to the primary with the smallest error, thereby defining a first best primary value set, and outputting the first best primary value set as the color of the first pixel; e. replacing the first best primary value set in the palette with the first modified set of input values from step b or the first projected modified set of input values from step c to produce a modified palette; f. calculating a difference between the first modified set of input values from step b or the first projected modified set of input values from step c and the first best primary value set from step e to derive a first error value; g. adding to the second set of input values the first error value to create a second modified set of input values; h. projecting the second modified set of input value on to the color gamut to produce a second projected modified set of input values when the second modified set of input values produced in step g is outside the color gamut; i. comparing the second modified set of input values from step g or the second projected modified set of input values from step h to the set of primary values corresponding to the primaries of the modified palette, selecting the set of primary values corresponding to the primary from the modified palette with the smallest error, thereby defining a second best primary value set, and outputting the second best primary value set as the color of the second pixel. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method for estimating an achievable gamut in a color electro-optic display, the method comprising:
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(1) measuring a test pattern to derive information about cross-talk among adjacent primaries in a color electro-optic display; (2) converting the measurements from step (1) to a blooming model that predicts the displayed color of arbitrary patterns of primaries on the color electro-optic display; (3) predicting actual display colors of patterns that would normally be used to produce colors on the convex hull of the primaries using the blooming model derived in step (2) (i.e. the nominal gamut surface); (4) describing the realizable gamut surface using the predictions made in step (3); and (5) rendering a color set by mapping input (source) colors to device colors using the realizable gamut surface model derived in step (4).
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18. A method of rendering a set of color image data on a color display device wherein the set of data are subjected to in this order, (i) a degamma operation (ii) HDR-type processing;
- (iii) hue correction (iv) gamut mapping; and
(v) a spatial dithering operation.
- (iii) hue correction (iv) gamut mapping; and
Specification