Method for color calibration and user terminal

Patent metadata

Field	Value
Publication number	US-9501841-B2
Application number	US-201314021423-A
Country	US
Kind code	B2
Filing date	Sep 9, 2013
Priority date	Sep 24, 2012
Publication date	Nov 22, 2016
Grant date	Nov 22, 2016

Abstract

Embodiments of the present invention provide a method for color calibration and a user terminal, which relate to the field of terminal display and are capable of compensating the colors of the displayed content on a screen according to the external light intensity, preventing content color distortion, and improving user experience. The embodiments of the present invention are used by a mobile terminal to calibrate screen colors according to external light.

First claim

What is claimed is:

1. A method for calibrating screen colors, the method comprising:
using a red green blue sensor to obtain separate channel readings of a red channel, a green channel and a blue channel;
receiving, by a processor, the channel reading of the red channel, the green channel, and the blue channel, the processor being coupled to the sensor;
obtaining, by the processor, emission energies of the red channel, the green channel and the blue channel according to the channel readings of the red channel, the green channel, and the blue channel received by the processor and screen reflectivity;
obtaining, by the processor, current self-luminous energies of the red, green, and blue of each picture element on the screen according to screen luminance and a red grayscale value, a green grayscale value, and a blue grayscale value of each picture element on a screen;
comparing the red grayscale value, the green grayscale value, and the blue grayscale value of each picture element on the screen, and determining two colors with the lowest grayscale values from among the red grayscale value, the blue grayscale value, and the green grayscale value of each picture element on the screen;
obtaining self-luminous energies upon compensation of only the two colors with the lowest grayscale values among the red, green, and blue of each picture element according to the emission energies of the red channel, the green channel, and the blue channel and the current self-luminous energies of the red, green, and blue of each picture element;
obtaining grayscale values upon compensation of only the two colors with the lowest grayscale values according to the self-luminous energies upon compensation of only the two colors with the lowest grayscale values;
transmitting the grayscale values upon compensation of only the two colors with the lowest grayscale values to a screen controller, the screen controller being coupled to the processor and a display screen; and
compensating colors on the display screen, by the screen controller, according to the grayscale values received by the screen controller.

2. The method according to claim 1 , wherein obtaining the emission energies of the red channel, the green channel, and the blue channel comprises:
receiving, by the processor, the channel reading of the red channel, the channel reading of the green channel, and the channel reading of the blue channel;
obtaining the screen reflectivity;
obtaining the emission energy of the red channel by multiplying the channel reading of the red channel and the screen reflectivity;
obtaining the emission energy of the green channel by multiplying the channel reading of the green channel and the screen reflectivity; and
obtaining the emission energy of the blue channel by multiplying the channel reading of the blue channel and the screen reflectivity.

3. The method according to claim 1 , wherein obtaining the current self-luminous energies of the red, green, and blue of each picture element on the screen comprises:
obtaining the screen luminance;
obtaining the red grayscale value, the green grayscale value, and the blue grayscale value of each picture element on the screen;
obtaining the current self-luminous energy of red in correspondence with the red grayscale value according to a mapping of the screen luminance, the color grayscale value, and the color self-luminous energy;
obtaining the current self-luminous energy of green in correspondence with the green grayscale value according to the mapping of the screen luminance, the color grayscale value, and the color self-luminous energy; and
obtaining the current self-luminous energy of blue in correspondence with the blue grayscale value according to the mapping of the screen luminance, the color grayscale value, and the color self-luminous energy.

4. The method according to claim 3 , wherein the mapping of the screen luminance, the color grayscale value, and the color self-luminous energy are preset in a user terminal.

5. The method according to claim 1 , wherein obtaining self-luminous energies upon compensation of only the two colors with the lowest grayscale values comprises:
determining that the red grayscale value is the largest;
obtaining, according to a first self-luminous energy formula, the green self-luminous energy upon compensation;
obtaining, according to a second self-luminous energy formula, the blue self-luminous energy upon compensation;
wherein the first self-luminous energy formula comprises:

G
s
′

=

G
s

*

R
s

+

R
r

R
s

-

G
r

wherein G s ′ indicates the green self-luminous energy upon compensation when the red grayscale value is the largest, G s indicates the current green self-luminous energy, R s indicates the current red self-luminous energy, R r indicates the channel reading of the red channel, and G r indicates the channel reading of the green channel; and
wherein the second self-luminous energy formula comprises:

B
s
′

=

B
s

*

R
s

+

R
r

R
s

-

B
r

wherein B s ′ indicates the blue self-luminous energy upon compensation when the red grayscale value is the largest, B s indicates the current blue self-luminous energy, G s indicates the current green self-luminous energy, G r indicates the channel reading of the green channel, and B r indicates the channel reading of the blue channel.

6. The method according to claim 1 , wherein obtaining self-luminous energies upon compensation of only the two colors with the lowest grayscale values comprises:
determining that the green grayscale value is the largest;
obtaining, according to a third self-luminous energy formula, the red self-luminous energy upon compensation; and
obtaining, according to a fourth self-luminous energy formula, the blue self-luminous energy upon compensation;
wherein the third self-luminous energy formula comprises:

R
s
′

=

R

Assignees

• Huawei Device Co Ltd
• Huawei Device Co Ltd

Inventors

• Yang Hong

Classifications

• G06T11/10 Primary

  Texturing; Colouring; Generation of textures or colours (retouching, inpainting or scratch removal G06T5/77) · CPC title

• G09G2320/0666

  for control of colour parameters, e.g. colour temperature · CPC title

• G09G2320/0693

  Calibration of display systems · CPC title

• G09G2360/144

  the light being ambient light · CPC title

• G09G5/02

  characterised by the way in which colour is displayed {(details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607)} · CPC title