Device for determining residual image of display device and method for determining residual image of display device

Patent metadata

Field	Value
Publication number	US-10291908-B2
Application number	US-201815950419-A
Country	US
Kind code	B2
Filing date	Apr 11, 2018
Priority date	Apr 11, 2017
Publication date	May 14, 2019
Grant date	May 14, 2019

Abstract

A method for determining residual images of a display device includes: dividing an image into a plurality of unit blocks; calculating a chroma, a hue, and a lightness of each unit block; applying a filter to the plurality of unit blocks to calculate a chroma difference, a hue difference, and a lightness difference; calculating a plurality of color difference based on the chroma, hue and lightness differences between the unit block and unit blocks adjacent to the unit block, a chroma weight constant, a hue weight constant, and a lightness weight constant; and calculating residual image indices for each unit block, where a residual image index is a maximum value of the plurality of color differences between the unit block and unit blocks adjacent to the unit block. The lightness weight constant is less than the chroma weight constant and the hue weight constant.

First claim

What is claimed is:

1. A method for determining residual images of a display device, the method comprising:
capturing an image displayed by a display device;
dividing the image into a plurality of unit blocks;
measuring CIE XYZ chromatic coordinates for each unit block;
transforming the CIE XYZ chromatic coordinates of each unit block into CIE Lab chromatic coordinates;
calculating a chroma, a hue, and a lightness of each unit block from the CIE Lab chromatic coordinates of each unit block;
applying a filter to the plurality of unit blocks to calculate a chroma difference, a hue difference, and a lightness difference, wherein the filter includes a filter center unit block and a plurality of filter adjacent unit blocks adjacent to the filter center unit block;
calculating a plurality of color differences based on the chroma difference, the hue difference, the lightness difference between the unit block and unit blocks adjacent to the unit block, a chroma weight constant, a hue weight constant, and a lightness weight constant;
calculating residual image indices for each unit block, wherein a residual image index is a maximum value of the plurality of color differences between the unit block and unit blocks adjacent to the unit block; and
storing the residual image indices in a database,
wherein the lightness weight constant is less than the chroma weight constant and the hue weight constant.

2. The method of claim 1 , wherein the lightness weight constant has a value of about 0.08 or more and about 0.15 or less, and each of the hue weight constant and the chroma weight constant has a value of about 1.

3. The method of claim 1 , wherein transforming the CIE XYZ chromatic coordinates of each unit block into the CIE Lab chromatic coordinates is performed based on a following equation:

L
*

=

116
⁢

f
⁡

(

Y
/

Y
n

)

-
16

a
*

=

500
⁡

[

f
⁡

(

X
/

X
n

)

-

f
⁡

(

Y
/

Y
n

)

]

b
*

=

200
⁡

[

f
⁡

(

Y
/

Y
n

)

-

f
⁡

(

Z
/

Z
n

)

]

f
⁡

(
I
)

=

{

I

1
/
3

for
⁢

⁢
I

>
0.008856

7.787
×
I

+

4
/
29

otherwise

,

wherein L*, a*, and b* denote the CIE Lab chromatic coordinates of a unit block, X, Y, and Z denote the CIE XYZ chromatic coordinates of the unit block, and each of Xn, Yn, and Zn denotes a value obtained by normalizing the CIE XYZ chromatic coordinates with respect to a standard white.

4. The method of claim 3 , wherein calculating the chroma, the hue, and the lightness of each unit block from the CIE Lab chromatic coordinates of each unit block comprises calculating the chroma, the hue, and the lightness of each unit block based on a following equation:
L′=L*
a ′=(1+ G ) a*

b′=b*
C ′=√{square root over ( a′ 2 +b′ 2 )}

h ′=tan −1 ( b′/a ′),

wherein L*, a*, and b* denote the CIE Lab chromatic coordinates of the unit block, L′ denotes a lightness, C′ denotes a chroma, h′ denotes a hue, and each of a′, b′, and G denotes a transform variable.

5. The method of claim 1 , wherein applying the filter to the image to calculate a chroma difference, a hue difference and a lightness difference comprises calculating the chroma diff

Assignees

• Samsung Display Co Ltd

Inventors

• Lee Hyunkoo
• Kim Sooyoung
• Lee Mintak
• Kim Kyuseok

Classifications

• H04N17/02 Primary

  for colour television signals · CPC title

• H04N17/004

  for digital television systems · CPC title

• G09G3/006 Primary

  Electronic inspection or testing of displays and display drivers, e.g. of LED or LCD displays (testing individual LED's G01R31/2635; testing lamps G01R31/44; testing of optical features of LCD displays G02F1/1309) · CPC title

• G09G2320/043

  Preventing or counteracting the effects of ageing · CPC title

• G09G2320/0257

  Reduction of after-image effects · CPC title