Mura detection device and method of detecting mura using the same

Patent metadata

Field	Value
Publication number	US-10733763-B2
Application number	US-201815955324-A
Country	US
Kind code	B2
Filing date	Apr 17, 2018
Priority date	Jul 31, 2017
Publication date	Aug 4, 2020
Grant date	Aug 4, 2020

Abstract

A mura detection device includes an XYZ coordinate system conversion unit which receives a photographed image of a display device and converts the photographed image into XYZ image data according to XYZ chromatic coordinates, a background image generation unit which generates background image data obtained by removing a part of the XYZ image data, a color difference calculation unit which generates color difference image data by comparing the photographed image and the background image data, and a mura data generation unit which calculates a color mura index value using the color difference image data.

First claim

What is claimed is:

1. A mura detection device, comprising:
an XYZ coordinate system conversion unit which receives a photographed image of a display device and convers the photographed image into XYZ image data according to XYZ chromatic coordinates;
a background image generation unit which generates background image data obtained by removing a part of the XYZ image data;
a color difference calculation unit which generates color difference image data by comparing the photographed image and the background image data; and
a mura data generation unit which calculates a color mura index value using the color difference image data,
wherein the color mura index value corresponds to a maximum luminance value of the color difference image data.

2. The mura detection device of claim 1 , further comprising:
a Lab coordinate system conversion unit which converts the XYZ image data into a Lab image data according to Lab chromatic coordinates.

3. The mura detection device of claim 2 ,
wherein the Lab coordinate system conversion unit converts the background image data into a Lab background image data according to the Lab chromatic coordinates.

4. The mura detection device of claim 3 ,
wherein the color difference calculation unit performs color difference calculation for the Lab image data and the Lab background image data according to DE2000 standard to generate the color difference image data.

5. The mura detection device of claim 1 ,
wherein the background image generation unit receives the XYZ image data and performs discrete cosine transform (DCT) of the XYZ image data, removes a part of data for high-frequency components, and performs inverse discrete cosine transform (IDCT), so as to generate the background image data.

6. A mura detection device, comprising:
an XYZ coordinate system conversion unit which receives a photographed image of a display device and convers the photographed image into XYZ image data according to XYZ chromatic coordinates;
a background image generation unit which generates background image data obtained by removing a part of the XYZ image data;
a color difference calculation unit which generates color difference image data by comparing the photographed image and the background image data;
a mura data generation unit which calculates a color mura index value using the color difference image data; and
a position weighting operation unit which combines the color difference image data with position weighted image data.

7. The mura detection device of claim 6 ,
wherein the color difference image data is combined with the position weighted image data by convolution operation.

8. The mura detection device of claim 6 ,
wherein the mage implemented by the position weighted image data has luminance which is lowered from a center of a display area toward an edge of the display area.

9. The mura detection device of claim 1 , further comprising:
an Luv coordinate system conversion unit which converts the XYZ image data into an Luv image data according to Luv chromatic coordinates.

10. The mura detection device of claim 9 ,
wherein the Luv coordinate system conversion unit converts the background image data into an Luv background image data according to the Luv chromatic coordinates.

11. The mura detection device of claim 10 ,
wherein the color difference calculation unit performs color difference calculation for the Luv image data and the Luv background image data according to Au′v′ standard to generate the color difference image data.

12. A method of detecting mura, the method comprising:
receiving a photographed image;
converting the photographed image into an XYZ image data according to XYZ chromatic coordinates;
removing a part of the XYZ image data to generate a background image data;
comparing the XYZ image data and the background image data to generate color difference image data; and
calculating a color mura index value using the color difference image data,
wherein the color mura index value corresponds to a maximum luminance value of the color difference image data.

13. The method of claim 12 , further comprising, after the generating the background image data:
converting the XYZ image data into a Lab image data according to Lab chromatic coordinates; and
converting the background image data into a Lab background image data according to the Lab chromatic coordinates.

14. The method of claim 13 ,
wherein, in the generating the color difference image data, color difference calculation for the Lab image data and the Lab background image data is performed according to DE2000 standard.

15. The method of claim 12 ,
wherein the generating the background image data includes:
performing discrete cosine transform of the XYZ image data;
removing a part of data for high-frequency components; and
performing inverse discrete cosine transform to generate the background image data.

16. The method of claim 12 , further comprising, after the generating the color difference image data:
performing convolution operation of the color difference image data and position weighted image data.

17. The method of claim 12 , further comprising, after the generating the background image data:
converting the XYZ image data into an Luv image data according to Luv chromatic coordinates; and
converting the background image data into an Luv background image data according to the Luv chromatic coordinates.

18. The method of claim 17 ,
wherein, in the generating the color difference image data, color difference calculation for the Luv image data and the Luv background image data is performed according to Δu′v′ standard.

Assignees

• Samsung Display Co Ltd

Inventors

• Lee Min Tak
• Kim Kyu Seok
• Kim Soo Young
• Yun Young Nam
• Lee Hyun Koo

Classifications

• G06T11/10

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

• G06T7/001 Primary

  using an image reference approach · CPC title

• G01N2021/9513

  Liquid crystal panels · CPC title

• G01N2021/8887

  based on image processing techniques · CPC title

• G01N21/95

  characterised by the material or shape of the object to be examined (G01N21/89 - G01N21/91, G01N21/94 take precedence) · CPC title