Granted Patent B2

US 12,219,298 · App. 17/753,460 · Granted Feb 4, 2025

Inventor: Xiaodong Zhang (Guangdong, CN)

Assignee: SHENZHEN TCL NEW TECHNOLOGY CO., LTD.

H04N9/67G09G5/06G09G5/10G09G2320/0626G09G2340/06G09G2360/16

Abstract

Claims (43)

1. A gamut mapping method, wherein comprising:

building a three-dimensional gamut model of a transmission end and a three-dimensional gamut model of a display end separately;

obtaining a brightness value of each of sampling points corresponding to image data of the transmission end on a basis of a three-dimensional mapping table;

performing equal-brightness cutting on the three-dimensional gamut model of the transmission end and the three-dimensional gamut model of the display end separately on a basis of the brightness values of the sampling points, and forming corresponding equal-brightness two-dimensional surfaces; and

obtaining a two-dimensional gamut surface of a transmission gamut of equal-brightness and a two-dimensional surface of a display gamut of equal-brightness;

building a mapping relationship between the RGB coordinates of each sampling point on an equal-brightness two-dimensional surface of the transmission end and the RGB coordinates of each sampling point on an equal-brightness two-dimensional surface of the display end according to pre-stored RGB coordinates of white points corresponding to the transmission end, RGB coordinates of white points corresponding to the display end, linear RGB coordinates of each sampling point on the equal-brightness two-dimensional surface, coordinates of intersection of a connecting line composed of the white point and each sampling point with the equal-brightness two-dimensional surface of the transmission end, and coordinates of intersection of the connecting line with the equal-brightness two-dimensional surface of the display end; and

mapping the RGB coordinates of each sampling point of the transmission end to the equal-brightness two-dimensional surface of the display end according to the mapping relationship.

2. The gamut mapping method as claimed in claim 1 , wherein the step of building the three-dimensional gamut model of the transmission end comprises:

performing a linearization processing on the image data obtained, and obtaining linear RGB coordinates of each of pixel points in the image data after the linearization processing;

determining a plurality of three-dimensional gamut coordinates converted from the linear RGB coordinates to an XYZ color model using preset matrix parameters and the linear RGB coordinates of each of the pixel points;

determining a plurality of three-dimensional gamut coordinates converted from the linear RGB coordinates to a Yxy color model according to the three-dimensional gamut coordinates converted to the XYZ color model; and

building the three-dimensional gamut model of the transmission end according to the three-dimensional gamut coordinate converted to the Yxy color model.

3. The gamut mapping method as claimed in claim 2 , wherein the step of performing the linearization processing on the obtained image data comprises:

converting a value range of the obtained image data from 0−(2 n −1) to 0-1.

4. The gamut mapping method as claimed in claim 1 , wherein the step of building the three-dimensional gamut model of the display end comprises:

obtaining display image data corresponding to display setting parameters on a display, normalizing the display image data, and obtaining linear RGB coordinates of each of pixel points in the display image data after a linearization processing;

determining a plurality of three-dimensional gamut coordinates converted from the linear RGB coordinates of each of the pixel points in the display image data to an XYZ color model according to a plurality of pre-stored display parameter matrices and the linear RGB coordinates of each of the pixel points in the display image data;

determining a plurality of three-dimensional gamut coordinates converted from the linear RGB coordinates of each of the pixel points in the display image data to a Yxy color model according to the three-dimensional gamut coordinates converted to the XYZ color model; and

building the three-dimensional gamut model of a display gamut of the display end according to the three-dimensional gamut coordinates converted to the Yxy color model.

5. The gamut mapping method as claimed in claim 1 , wherein the step of performing equal-brightness cutting on the three-dimensional gamut model of the transmission end and the three-dimensional gamut model of the display end separately on the basis of the brightness values of the sampling points, and forming the corresponding equal-brightness two-dimensional surfaces comprises:

calculating transmission three-dimensional gamut coordinates of each sampling point in the three-dimensional gamut model of the transmission end on a basis of pixel point values of each sampling point; and

performing equal-brightness cutting on the three-dimensional gamut model of the transmission end and the three-dimensional gamut model of the display end separately according to brightness values contained in the transmission three-dimensional gamut coordinates, and obtaining a series of equal-brightness two-dimensional surfaces.

6. The gamut mapping method as claimed in claim 5 , wherein the step of calculating transmission three-dimensional gamut coordinates of each sampling point in the three-dimensional gamut model of the transmission end on the basis of pixel point values of each sampling point comprises:

performing a linearization processing on each sampling point, and obtaining linear RGB coordinates of each sampling point after the linearization processing;

determining three-dimensional gamut coordinates converted from the linear RGB coordinates of each sampling point to an XYZ color model according to preset matrix parameters and the linear RGB coordinates of each sampling point; and

determining transmission three-dimensional gamut coordinates converted from the linear RGB coordinates of each sampling point to a Yxy color model according to the three-dimensional gamut coordinate converted to the XYZ color model.

7. The gamut mapping method as claimed in claim 1 , wherein a relational expression of the mapping relationship between the RGB coordinates of each sampling point on the equal-brightness two-dimensional surface of the transmission end and the RGB coordinates of each sampling point on the equal-brightness two-dimensional surface of the display end is:

WA i /WE=WA O /WF

X AO =( x Ai −x w )*( x F −x w )/( x E −x w )

y AO =( y Ai −y w )*( y F −y w )/( y E −y w )

wherein W(x w ,y w ) is the pre-stored RGB coordinate of the white points corresponding to the transmission end, A i (x Ai ,y Ai ) is a linear RGB coordinate of given sampling point, E(x E ,y E ) is a coordinate of intersection of a connecting line composed of W(x w ,y w ) and A i (x Ai ,y Ai ) with the equal-brightness two-dimensional surface of the transmission end, F(x F ,y F ) is a coordinate of intersection of the connecting line with the equal-brightness two-dimensional surface of the display end, WA i is a straight line composed of two points W(x w ,y w ) and A i (x Ai ,y Ai ), WE is a straight line composed of two points W(x w ,y w ) and E(x E ,y E ), W A O is a straight line composed of two points W(x w ,y w ) and A O (x AO ,y AO ), and WF is a straight line composed of two points W(x w ,y w ) and F(x F ,y F ).

8. The gamut mapping method as claimed in claim 7 , wherein the step of mapping the RGB coordinates of each sampling point of the transmission end to the equal-brightness two-dimensional surface of the display end according to the mapping relationship comprises:

calculating linear RGB coordinates of each sampling point on the equal-brightness two-dimensional surface of the transmission end mapping to linear RGB coordinates on the equal-brightness two-dimensional surface of the display end according to the pre-stored RGB coordinates of the white points corresponding to the transmission end, the RGB coordinates of the white points corresponding to the display end, the linear RGB coordinates of each sampling point on the equal-brightness two-dimensional surface, the coordinates of intersection of the connecting line composed of the white point and each sampling point with the equal-brightness two-dimensional surface of the transmission end, and the coordinates of intersection of the connecting line with the equal-brightness two-dimensional surface of the display end, and the relational expression of the mapping relationship; and

combining the linear RGB coordinates of each sampling point on the equal-brightness two-dimensional surface of the display end with the brightness values, converting the combined linear RGB coordinates and the brightness values into the mapping data, and outputting and displaying the mapping data.

9. The gamut mapping method as claimed in claim 8 , wherein the step of combining the linear RGB coordinates of each sampling point on the equal-brightness two-dimensional surface of the display end with the brightness values, converting the combined linear RGB coordinates and the brightness values into the mapping data, and outputting and displaying the mapping data comprises:

obtaining values of a three-dimensional RGB of a target gamut according to a combination of values of a two-dimensional pixel of the target gamut and its brightness values;

converting the values of the three-dimensional RGB of the target gamut to three-dimensional gamut coordinates of an XYZ color model from three-dimensional gamut coordinates of a Yxy color model according to a conversion formula between RGB values of the XYZ color model and RGB values of the Yxy color model; and

calculating outputting image data according to the three-dimensional gamut coordinates of the target gamut converted to the XYZ color model and preset display parameter matrices of a display.

10. The gamut mapping method as claimed in claim 8 , wherein the step of combining the linear RGB coordinates of each sampling point on the equal-brightness two-dimensional surface of the display end with the brightness values, converting the combined linear RGB coordinates and the brightness values into the mapping data, and outputting and displaying the mapping data comprises:

filling the mapping data with a linear interpolation, and outputting and displaying the filled mapping data.

11. The gamut mapping method as claimed in claim 1 , wherein before the step of obtaining the brightness values of each sampling point corresponding to the image data of the transmission end on the basis of the three-dimensional mapping table, the gamut mapping method further comprises steps of:

calculating pre-matrix parameters according to two-dimensional coordinates of an RGB vertex gamut of a signal source end and two-dimensional coordinates of white points of the signal source end; and

calculating preset display parameter matrices according to two-dimensional coordinates of an RGB vertex gamut of the display end and two-dimensional coordinates of white points of the display end.

Assignments (2)

Priority Claims (1)

Continuity (1)

References Cited (22)