Apparatus for enhancing brightness uniformity of displayed image, display apparatus, and method for displaying image

Patent metadata

Field	Value
Publication number	US-10490145-B2
Application number	US-201715571615-A
Country	US
Kind code	B2
Filing date	Jun 2, 2017
Priority date	Sep 21, 2016
Publication date	Nov 26, 2019
Grant date	Nov 26, 2019

Abstract

The present application discloses a method for displaying image using a display panel. The method includes receiving a frame of image data, which is divided into a first portion and a second portion based on that each sub-pixel in the first portion has an initial grayscale value smaller than that of each subpixel in the second portion. The method includes converting the frame of image data into N frames of image data. Each sub-pixel in the first portion is provided with a first grayscale value in K of the N frames and a second grayscale value in N-K of the N frames, and each sub-pixel in the second portion is retained with its initial grayscale value. N is no smaller than 2 and K varies from 1 to N−1. The method includes displaying each of the N frames of images respectively based on the N frames of image data according to a frame refreshing frequency.

First claim

What is claimed is:

1. An apparatus for enhancing brightness uniformity of displayed image, comprising:
a processor configured to convert a frame of image data, which is divided into a first portion and a second portion based on that each sub-pixel in the first portion has an initial grayscale value smaller than that of each subpixel in the second portion, into N frames of image data;
wherein the apparatus is configured to receive the frame of image data comprising a plurality of initial grayscale values respectively corresponding to a plurality of sub-pixels;
wherein each sub-pixel in the first portion is provided with a first grayscale value in K of the N frames of image data and a second grayscale value in N-K of the N frames of image data; and
each sub-pixel in the second portion is retained with its initial grayscale value in each of the N frames of image data, wherein N is an integer equal to or greater than 2 and K varies from 1 to N−1.

2. The apparatus of claim 1 , further comprising a display panel configured to display a frame of image based on each of the N frames of image data according to a frame refreshing frequency.

3. The apparatus of claim 2 , wherein the display panel is configured to provide a grayscale image based on each of the plurality of initial grayscale values that is smaller than a threshold grayscale value, a maximum brightness value of the grayscale image being measured by a camera; and
the processor is configured to deduce a set of gamma curve data comprising a set of gamma-corrected brightness values corresponding to a set of grayscale values, the first grayscale value and the second grayscale value being two adjacent grayscale values corresponding to two gamma-corrected brightness values in the set of gamma curve data.

4. The apparatus of claim 3 , wherein the processor is configured to select the first grayscale value, the second grayscale value, and a value of K so that a difference between a modified brightness value for sub-pixels in the first portion having a particular initial grayscale value and a superposition value of the two gamma-corrected brightness values respectively weighted with a first ratio of K/N and a second ratio of (N-K)/N is minimal.

5. The apparatus of claim 3 , wherein the modified brightness value is equal to a maximum value among all sub-pixels corresponding to the particular initial grayscale value, multiplied by a factor.

6. The apparatus of claim 5 , wherein the processor is configured to select a first value smaller than 1 as the factor to obtain a first value of the modified brightness value used in a first iteration of converting the frame of image data to the N frames of image data; and
the display panel is configured to display a frame of image based on each of the N frames of image data which is subjected to a determination whether a brightness uniformity of a displayed frame of image meets a threshold uniformity.

7. The apparatus of claim 6 , wherein the processor is configured to:
select a second value larger than the first value but still smaller than 1 as the factor to obtain a second value of the modified brightness value used in a second iteration of converting the frame of image data to the N frames of image data until the brightness uniformity of the displayed frame of image based on each of the N frames of images meets the threshold uniformity; and
determine that the second value of the modified brightness value to be corresponding to the particular initial grayscale value.

8. The apparatus of claim 1 , wherein N is selected to be equal to or smaller than 4.

9. The apparatus of claim 2 , wherein the frame refreshing frequency is N×60 Hz.

10. A display apparatus comprising the apparatus of claim 1 .

11. A method for displaying image using a display panel, the method comprising:
receiving a frame of image data comprising a plurality of initial grayscale values respectively corresponding to a plurality of sub-pixels; and
converting the frame of image data, which is divided into a first portion and a second portion based on that each sub-pixel in the first portion has an initial grayscale value smaller than that of each subpixel in the second portion, into N frames of image data;
wherein each sub-pixel in the first portion is provided with a first grayscale value in K of the N frames of image data and a second grayscale value in N-K of the N frames of image data; and
each sub-pixel in the second portion is retained with its initial grayscale value in each of the N frames of image data, wherein N is an integer equal to or greater than 2 and K varies from 1 to N−1.

12. The method of claim 11 , further comprising displaying each of the N frames of images respectively based on the N frames of image data according to a frame refreshing frequency.

13. The method of claim 12 , wherein the frame refreshing frequency is N×60 Hz.

14. The method of claim 11 , comprising displaying a grayscale image of each of the initial grayscale values that are smaller than a threshold grayscale value to measure a corresponding maximum brightness value and to deduce a set of gamma curve data comprising a set of gamma-corrected brightness values corresponding to a set of grayscale values.

15. The method of claim 14 , wherein the first grayscale value and the second grayscale value are two adjacent grayscale values corresponding to two gamma-corrected brightness values in the set of gamma curve data.

16. The method of claim 15 , wherein the first grayscale value, the second grayscale value, and a value of K are selected so that a difference between a modified brightness value for all sub-pixels in the first portion having a particular initial grayscale value and a superposition value of the two gamma-corrected brightness values respectively weighted with a first ratio of KN and a second ratio of (N-K)/N is minimal.

17. The method of claim 16 , wherein converting the frame of image data comprises determining the modified brightness value to be equal to a maximum brightness value among all sub-pixels corresponding to the particular initial grayscale value multiplied by a factor.

18. The method of claim 17 , wherein converting the frame of image data further comprises:
selecting the factor smaller than 1 to calculate a first value of the modified brightness value used in a first iteration of converting the frame of image data to the N frames of image data;
displaying an image based on each of the N frames of image data; and
determining whether a brightness uniformity of a displayed frame of image meets a threshold uniformity.

19. The method of claim 18 , wherein converting the frame of image data further comprises:
increasing the factor to calculate a second value of the modified brightness value used in a second iteration of converting the frame of image data to the N frames of image data until the brightness uniformity of the displayed frame of image based on each of the N frames of images meets the threshold uniformity; and
determining that the second value of the modified brightness value to be corresponding to the particular initial grayscale value.

20. The method of claim 11 , wherein N is selected to be equal to or smaller than 4.

Assignees

• Boe Technology Group Co Ltd
• Beijing Boe Special Display Tech Co Ltd

Inventors

• Zhu Huizhong
• Liu Junguo
• Sun Shenglin

Classifications

• G09G2320/0693

  Calibration of display systems · CPC title

• G09G3/2022

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• G09G2320/0271

  Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping · CPC title

• G09G2360/147

  the originated light output being determined for each pixel · CPC title

• G09G3/36

  using liquid crystals · CPC title