US 10,242,461 B1Granted

Method to improve overlay mapping of out-of-gamut

AssigneeShenzhen China Star Optoelectronics Semiconductor Display Technology Co., Ltd.

InventorYang Rao

Life of this patent

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Abstract

The present disclosure relates a method to improve overlay mapping of out-of-gamut. The method includes: step 10, converting a RGB digital value to a L*a*b* value of a Lab color space; step 20, determining a hue plane where the color point P located, and further determining values of a hue angle H, a color saturation C, and a brightness L; step 30, determining a reference color point Pi by combing intersections color point PC and color point PS with the color point Lm and a parameter α; step 40, determining whether the color point P inside or outside a line |LmPi|; and step 50, converting a L*a*b* value into a RGB value in the target gamut. The method to improve the overlay mapping of out-of-gamut according to the present disclosure causes multiple colors to no longer be mapped to the same color point.

Claims15

Dependent claims

A method to improve overlay mapping of out-of-gamut, comprising:

step 10, converting a RGB digital value of a color point P in a source gamut to a L*a*b* value of a Lab color space;
step 20, determining a hue plane where the color point P located by the L*a*b* value, and further determining values of a hue angle H, a color saturation C, and a brightness L of the color point P;
step 30, serving intersections of a line defined by the color point P and a color point Lm on a brightness axis of the hue plane, and a boundary of a target gamut, and a boundary of the source gamut as a color point PC and a color point PS respectively, and determining a reference color point Pi by combing with the color point Lm and a parameter α:
LPi=α(LLm−LPC)+LPC
CPi=α(CLm−CPC)+CPC
wherein, the parameter α is 0˜1;
step 40, determining whether the color point P inside a line |LmPi| or outside the |LmPi|;
if it is inside, the color point P is still the color point P after mapping to the target gamut, and the process goes to step 50;
if it is outside, the color point P is mapped to the target gamut as a color point P′:
L
P
′
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P
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;
step 50, converting a L*a*b* value of the color point P mapped to the target gamut into a RGB value in the target gamut.

80 more elements

A method to improve overlay mapping of out-of-gamut, comprising:

step 10, converting a RGB digital value of a color point P in a source gamut to a L*a*b* value of a Lab color space;
step 20, determining a hue plane where the color point P located by the L*a*b* value, and further determining values of a hue angle H, a color saturation C, and a brightness L of the color point P;
step 30, serving intersections of a line defined by the color point P and a color point Lm on a brightness axis of the hue plane, and a boundary of a target gamut and a boundary of the source gamut as a color point PC and a color point PS respectively, and determining a reference color point Pi by combing with the color point Lm and a parameter α:
LPi=α(LLm−LPC)+LPC
CPi=α(CLm−CPC)+CPC
wherein, the parameter α is 0˜1;
step 40, determining whether the color point P inside a line |LmPi| or outside the |LmPi|;
if it is inside, the color point P is still the color point P after mapping to the target gamut, and the process goes to step 50;
if it is outside, the color point P is mapped to the target gamut as a color point P′:
L
P
′
=
(
L
P
c
-
L
P
i
)
⁢
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L
P
-
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P
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;
step 50, converting a L*a*b* value of the color point P mapped to the target gamut into a RGB value in the target gamut;
wherein the color point Lm is a midpoint of a maximum brightness on the brightness axis of the hue plane;
wherein the step 10 comprises:
step 11, inputting a RGB numerical value of the color point P in the source gamut;
step 12, converting the RGB numerical value into a RGB optical value by gamma correction;
step 13, converting the RGB optical value into a XYZ tristimulus value by a conversion matrix;
step 14, converting the XYZ tristimulus value into the L*a*b* value of the Lab color space;
wherein the gamma correction uses the gamma 2.2 standard;
wherein the step 50 comprises:
step 51, converting the L*a*b value into a XYZ tristimulus value;
step 52, converting the XYZ tristimulus value into a RGB optical value by an inverse conversion matrix;
step 53, converting the RGB optical value into a RGB numerical value by gamma correction;
step 54, outputting the RGB numerical value of the color point P mapped to the target gamut;
wherein the gamma correction uses the gamma 2.2 standard.

93 more elements

Dependencies are inferred from the claim text.

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Abstract