Color detection method and terminal

Patent metadata

Field	Value
Publication number	US-11284013-B2
Application number	US-201716627636-A
Country	US
Kind code	B2
Filing date	Jun 30, 2017
Priority date	Jun 30, 2017
Publication date	Mar 22, 2022
Grant date	Mar 22, 2022

Abstract

A terminal device calibrates a to-be-detected image based on a light source color temperature and scene brightness that are obtained during imaging of the to-be-detected image and based on a preset reference color card image set to restore a real color of the to-be-detected image to a greatest extent.

First claim

What is claimed is:

1. A method implemented by a terminal, the method comprising:
obtaining a first light source color temperature and a first scene brightness that are used during imaging of a to-be-detected image;
selecting a reference color card image from a preset reference color card data set based on the first light source color temperature and a correspondence between the reference color card image and a second light source color temperature used during imaging of the reference color card image, wherein the preset reference color card data set stores a plurality of reference color card images and related parameter information used during imaging of each of the reference color card images;
determining target image brightness of the to-be-detected image based on the first scene brightness and based on a preset functional relationship between image brightness and scene brightness;
adjusting a brightness of the reference color card image to the target image brightness to obtain an adjusted reference color card image;
setting the adjusted reference color card image as a calibration color card image;
calibrating the to-be-detected image based on a prestored relationship between a color of a standard color card image and a color of the calibration color card image to obtain a calibrated image; and
determining a color value of the calibrated image.

2. The method of claim 1 , wherein selecting the reference color card image comprises selecting, from the reference color card images, a first reference color card image for which a third light source color temperature used during imaging of the first reference color card image is closest to the first light source color temperature.

3. The method of claim 1 , wherein selecting the reference color card image from comprises:
selecting, from the reference color card images, at least one reference color card image, wherein a difference between a third light source color temperature used during imaging of the at least one reference color card image and the first light source color temperature is within a specified threshold range; and
selecting one reference color card image from the at least one reference color card image as the reference color card image.

4. The method of claim 1 , further comprising analyzing a correspondence between a scene brightness used during imaging of each of the reference color card images and an image brightness of each of the reference color card images to obtain the preset functional relationship.

5. The method of claim 1 , wherein calibrating the to-be-detected image comprises:
determining color calibration information based on a color value of a color block in each same position of the standard color card image and the calibration color card image, wherein the color calibration information represents a mapping relationship between a color value of the standard color card image and a color value of the calibration color card image; and
calibrating a color of the to-be-detected image based on the color calibration information.

6. The method of claim 1 , wherein determining the color value of the calibrated image comprises determining the color value of the calibrated image based on a color value of each pixel of the calibrated image.

7. An electronic device, comprising:
a non-transitory memory configured to store instructions; and
a processor coupled to the non-transitory memory and configured to execute the instructions to cause the electronic device to:
obtain a first light source color temperature and a first scene brightness that are used during imaging of a to-be-detected image;
select a reference color card image from a preset reference color card data set based on the first light source color temperature and a correspondence between the reference color card image and a second light source color temperature used during imaging of the reference color card image, wherein the preset reference color card data set stores a plurality of reference color card images and related parameter information used during imaging of each of the reference color card images;

determine target image brightness of the to-be-detected image based on the first scene brightness and on a preset functional relationship between image brightness and scene brightness;
adjust a brightness of the reference color card image to the target image brightness to obtain an adjusted reference color card image;
set the adjusted reference color card image as a calibration color card image;
calibrate the to-be-detected image based on a prestored relationship between a color of a standard color card image and a color of the calibration color card image to obtain a calibrated image; and
determine a color value of the calibrated image.

8. The electronic device of claim 7 , wherein the processor is further configured to execute the instructions to cause the electronic device select, from the preset reference color card data set, a first reference color card image for which a third light source color temperature used during imaging of the first reference color card image is closest to the first light source color temperature.

9. The electronic device of claim 7 , wherein the processor is further configured to execute the instructions to cause the electronic device to:
select, from the reference color card images, at least one reference color card image, wherein a difference between a third light source color temperature used during imaging of the at least one reference color card image and the first light source color temperature is within a specified threshold range; and
select one reference color card image from the at least one reference color card image as the reference color card image.

10. The electronic device of claim 7 , wherein the processor is further configured to execute the instructions to cause the electronic device to analyze a correspondence between a scene brightness used during imaging of each of the reference color card images and an image brightness of each of the reference color card images.

11. The electronic device of claim 7 , wherein the processor is further configured to execute the instructions to cause the electronic device to:
determine color calibration information based on a color value of a color block in each same position of the standard color card image and the calibration color card image, wherein the color calibration information represents a mapping relationship between a color value of the standard color card image and a color value of the calibration color card image; and
calibrate a color of the to-be-detected image based on the color calibration information.

12. The electronic device of claim 7 , wherein the processor is further configured to execute the instructions to cause the electronic device to determine the color value of the calibrated image based on a color value of each pixel of the calibrated image.

13. A computer program product comprising computer-executable instructions for storage on a non-transitory computer-readable medium that, when executed by a processor, cause a terminal to:
obtain a first light source color temperature and a first scene brightness that are used during imaging of a to-be-detected image;
select a reference color card image from a preset reference color card data set based on the first light source color temperature and a correspondence between the reference color card image and a second light source color temperature used during imaging of the reference color card image, wherein the preset reference color card data set stores a plurality of reference color card images and related parameter information used during imaging of each

Assignees

• Huawei Tech Co Ltd

Inventors

• Lu Henghui
• Liu Hao
• Gao Wenmei

Classifications

• G06T7/90 Primary

  Determination of colour characteristics · CPC title

• H04N23/74 Primary

  by influencing the scene brightness using illuminating means · CPC title

• H04N23/88

  for colour balance, e.g. white-balance circuits or colour temperature control · CPC title

• H04N23/70

  Circuitry for compensating brightness variation in the scene · CPC title

• H04N23/56

  provided with illuminating means · CPC title