Luminance management for high dynamic range displays

Patent metadata

Field	Value
Publication number	US-2018338104-A1
Application number	US-201515777195-A
Country	US
Kind code	A1
Filing date	Nov 18, 2015
Priority date	Nov 18, 2015
Publication date	Nov 22, 2018
Grant date	—

Abstract

Managing luminance of video streams for display on HDR displays is provided. The luminance values of frames of a video stream can be monitored, and an over-bright frame can be determined if a luminance increase greater than a given luminance change within a given period of time. When a brightness jump exceeding given parameters is detected, the luminance values of the over-bright frame can be reduced. For example, luminance values can be reduced by reducing the luminance values of the over-bright frame such that the change in the average luminance is brought below the given value, and the luminance values of the modified frame can maintain relative luminances among pixels. A modified frame can be determined from the over-bright frame based on the reduced luminance values. The modified frame can be inserted into the video stream and transmitted to an HDR display to be displayed.

First claim

1 . A system comprising:
a processor; and a memory storing instructions configured to cause the processor to: obtain characteristics of a HDR display; obtain luminance values of a video stream; determine an increase in a luminance of the video stream that exceeds a luminance change within a time window, wherein the increase in the luminance occurs in a frame of the video stream; reduce the luminance values of the frame according to the characteristics of the HDR display; and determine a modified frame base on the reduced luminance values.

2 . The system of claim 1 , wherein the luminance is an average luminance and the increase in the average luminance is determined based on a difference between the average luminance of the frame and the average luminance of a frame at the beginning of the time window.

3 . (canceled)

4 . The system of claim 1 , wherein the characteristics of the HDR display include at least one of a maximum brightness, a brightness setting, a gamma value, and a screen size.

5 . The system of claim 1 ,
wherein the instructions further cause the processor to obtain information of an environment of the HDR display, and to determine the luminance change based on the information of the environment.

6 . The system of claim 5 , wherein the information of the environment includes at least one of an ambient light value and a viewing distance.

7 . The system of claim 1 , wherein the instructions further cause the processor to reduce the luminance values of subsequent frames in the video stream such that an amount of the reduction of the luminance values decreases.

8 . A non-transitory computer-readable medium storing computer-executable instructions executable to perform a method for managing the luminance of a video stream, the method comprising:
obtaining characteristics of an HDR display; obtaining luminance values of the video stream; determining an increase in a luminance of the video stream that exceeds a luminance change within a time window, wherein the increase in the luminance occurs in a frame of the video stream; reducing the luminance values of the frame according to the characteristics of the HDR display; and determining a modified frame base on the reduced luminance values.

9 . The non-transitory computer-readable medium of claim 8 , wherein the luminance is an average luminance and the increase in the average luminance is determined based on a difference between the average luminance of the frame and the average luminance of a frame at the beginning of the time window.

10 . (canceled)

11 . The non-transitory computer-readable medium of claim 8 , wherein the characteristics of the HDR display include at least one of a maximum brightness, a brightness setting, a gamma value, and a screen size.

12 . The non-transitory computer-readable medium of claim 8 , wherein the method further comprises:
obtaining information of an environment of an HDR display; and determining the luminance change based on the information of the environment.

13 . The non-transitory computer-readable medium of claim 12 , wherein the information of the environment includes at least one of an ambient light value and a viewing distance.

14 . The non-transitory computer-readable medium of claim 8 , wherein the method further comprises:
reducing the luminance values of subsequent frames in the video stream such that an amount of the reduction of the luminance values decreases.

15 . A method for managing the luminance of a video stream, the method comprising:
obtaining characteristics of an HDR display; obtaining luminance values of the video stream; determining an increase in a luminance of the video stream that exceeds a luminance change within a time window, wherein the increase in the luminance occurs in a frame of the video stream; reducing the luminance values of the frame according to the characteristics of the HDR display; and determining a modified frame base on the reduced luminance values.

16 . The method of claim 15 , wherein the luminance is an average luminance and the increase in the average luminance is determined based on a difference between the average luminance of the frame and the average luminance of a frame at the beginning of the time window.

17 . (canceled)

18 . The method of claim 15 , wherein the characteristics of the HDR display include at least one of a maximum brightness, a brightness setting, a gamma value, and a screen size.

19 . The method of claim 15 , further comprising:
obtaining information of an environment of an HDR display; and determining the luminance change based on the information of the environment.

20 . The method of claim 19 , wherein the information of the environment includes at least one of an ambient light value and a viewing distance.

21 . The method of claim 15 , further comprising:
reducing the luminance values of subsequent frames in the video stream such that an amount of the reduction of the luminance values decreases.

Assignees

• Thomson Licensing

Inventors

• Pines Joshua
• Weaver Gregory S

Classifications

• G09G2360/16

  Calculation or use of calculated indices related to luminance levels in display data · CPC title

• G09G2320/0626

  for control of overall brightness · CPC title

• G09G5/10 Primary

  Intensity circuits · CPC title

• H04N21/44

  Processing of video elementary streams, e.g. splicing a video clip retrieved from local storage with an incoming video stream or rendering scenes according to encoded video stream scene graphs · CPC title

• G09G2320/103

  Detection of image changes, e.g. determination of an index representative of the image change · CPC title