Method to control display device screen brightness and strength of dynamic range compression based on ambient light level

• US 9,489,920 B2
• Filed: 02/21/2014
• Issued: 11/08/2016
• Est. Priority Date: 08/22/2011
• Status: Active Grant

• Current Assignee: Arm Limited (SoftBank Group Corp.)
• Original Assignee: Apical Limited (SoftBank Group Corp.)
• Inventors: Tusch, Michael
• Primary Examiner(s): AWAD, AMR A
• Assistant Examiner(s): Lui, Donna
• Application Number:
  US14/187,180
• Publication Number:
  US 20140168288A1
• Time in Patent Office: 991 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 2320/0271 Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/066 for control of contrast
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 5/00 Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators image data processing or generation, in general G06T
• CPC Class Codes: G09G 5/10 Intensity circuits

Abstract

A method of controlling in a display device screen brightness and strength of dynamic range compression of display data in dependence on ambient light level. Ambient light level values are required from one or more ambient light sensors. The ambient light level values are averaged using a first method to obtain a first average value and using a second, different method to obtain a second average value. The first average value is used for controlling the screen brightness and the second average value is used for controlling the strength of the dynamic range compression.

Claims

1. A method of controlling in a display device screen brightness and strength of dynamic range compression of display data in dependence on ambient light level values, the method comprising:

acquiring ambient light level values from one or more ambient light sensors;

averaging the ambient light level values using a first method to obtain a first average value, wherein the first method uses a first temporal averaging;

averaging the ambient light level values using a second method to obtain a second average value, wherein the second method uses a second temporal averaging that is different from the first temporal averaging, such that the first average value is different from the second average value, and wherein at least one of the first and second methods uses moving window averaging;

using the first average value for controlling the screen brightness;

using the second average value for controlling the strength of dynamic range compression; and

resetting at least one moving window averaging associated with the at least one of the first and second methods that uses the at least one moving window averaging, when at least one of one or more latest acquired ambient light level values deviates from a corresponding current first or second average value by more than a predetermined threshold value.

2. The method of claim 1, wherein the first temporal averaging is over a longer period than the second temporal averaging.

3. The method of claim 1, wherein the first moving window averaging is reset.

4. The method of claim 1, wherein the second moving window averaging is reset.

5. The method of claim 4, wherein the dynamic range compression is locally adaptive.

6. The method of claim 1, wherein the first and the second moving window averaging are reset.

7. The method of claim 6, wherein the dynamic range compression is locally adaptive.

8. The method of claim 1, wherein the second temporal averaging uses recursive averaging.

9. The method of claim 1, wherein the dynamic range compression is locally adaptive.

10. A display control system for controlling screen brightness and strength of dynamic range compression of display data in a display device based on ambient light level values, the display control system comprising:

a processing component configured to;

acquire ambient light level values from one or more ambient light sensors;

average the ambient light level values using a first method to obtain a first average value, wherein the first method uses a first temporal averaging;

average the ambient light level values using a second method to obtain a second average value, wherein the second method uses a second temporal averaging that is different from the first temporal averaging, such that the first average value is different from the second average value, and wherein at least one of the first and second methods uses moving window averaging;

use the first average value for controlling the screen brightness;

use the second average value for controlling the strength of the dynamic range compression; and

reset at least one moving window average associated with the at least one of the first and second methods that uses the at least one moving window averaging, when at least one of one or more latest acquired ambient light level values deviates from a corresponding current first or second average value by more than a predetermined threshold value.

11. A non-transitory computer-readable storage medium comprising computer-executable instructions, which, when executed by a processor, cause a computing device to perform a method of controlling in a display device screen brightness and strength of dynamic range compression of display data in dependence on ambient light level values, the method comprising:

acquiring ambient light level values from one or more ambient light sensors;

averaging the ambient light level values using a first method to obtain a first average value, wherein the first method uses a first temporal averaging;

averaging the ambient light level values using a second method to obtain a second average value, wherein the second method uses a second temporal averaging that is different from the first temporal averaging, such that the first average value is different from the second average value, and wherein at least one of the first and second methods uses moving window averaging;

using the first average value for controlling the screen brightness;

using the second average value for controlling the strength of the dynamic range compression, and;

resetting at least one moving window averaging associated with the at least one of the first and second methods that uses the at least one moving window averaging, when at least one of one or more latest acquired ambient light level values deviates from a corresponding current first or second average value by more than a predetermined threshold value.

12. A system for controlling screen brightness and strength of dynamic range compression of display data based on ambient light level values, the system comprising:

a display device; and

a processing component configured to;

acquire ambient light level values from one or more ambient light sensors;

average the ambient light level values using a first method to obtain a first average value, wherein the first method uses a first temporal averaging;

average the ambient light level values using a second method to obtain a second average value, wherein the second method uses a second temporal averaging that is different from the first temporal averaging, such that the first average value is different from the second average value, and wherein at least one of the first and second methods uses moving window averaging;

use the first average value for controlling the screen brightness on the display device;

use the second average value for controlling the strength of dynamic range compression on the display device; and

reset at least one moving window averaging associated with the at least one of the first and second methods that uses the at least one moving window averaging, when at least one of one or more latest acquired ambient light level values deviates from a corresponding current first or second average value by more than a predetermined threshold value.