Methods and Systems for Display Source Light Management with Rate Change Control

• US 20100053222A1
• Filed: 08/30/2008
• Published: 03/04/2010
• Est. Priority Date: 08/30/2008
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Kerofsky, Louis Joseph
• Granted Patent: US 9,330,630 B2
• Time in Patent Office: Days
• US Class Current: 345/690
• CPC Class Codes: G09G 2320/0276 for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
• 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 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2340/16 Determination of a pixel data signal depending on the signal applied in the previous frame
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 2360/18 Use of a frame buffer in a display terminal, inclusive of the display panel
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 5/10 Intensity circuits

Abstract

Elements of the present invention relate to systems and methods for modifying or adjusting a display source light illumination level based on power consumption goals. In some embodiments, a rate control parameter may be used to limit the rate at which the illumination level is varied. In some embodiments, image content analysis may be used to determine the value of the rate control parameter.

Claims

1. A method for modifying a display source light illumination level, said method comprising:

a) determining a relative source light parameter representing the relative amount that a source light level can be reduced with adequate compensation through brightness preservation processing;

b) determining a display power difference value;

c) determining a previous frame peak source light illumination level; and

d) modifying said previous frame peak source light illumination level with said relative source light parameter and said display power difference value, thereby creating a current-frame modified source light illumination level;

2. A method for modifying a display source light illumination level, said method comprising:

a) determining a relative source light parameter representing the relative amount that a source light level can be reduced with adequate compensation through brightness preservation processing;

b) determining a display power target value;

c) determining actual display power value;

d) subtracting said actual display power value from said display power target value, thereby creating a power difference value;

e) multiplying said power difference value by a rate control parameter, thereby creating a power adjustment;

f) determining a previous frame peak source light illumination level;

g) adding said power adjustment to said previous frame peak source light illumination level, thereby creating a current frame peak source light illumination level;

h) ensuring that said current frame peak source light illumination level falls within an allowable range defined by a minimum limit and a maximum limit; and

i) multiplying said current frame peak source light illumination level by said relative source light parameter, thereby creating a current-frame modified source light illumination level.

3. A method as described in claim 2 wherein said display target power value is a source light illumination level target.

4. A method as described in claim 2 wherein said actual display power value is an actual source light illumination level.

5. A method as described in claim 2 wherein said display target power value is a power consumption target.

6. A method as described in claim 2 wherein said actual display power value is an actual battery power consumption value.

7. A method as described in claim 2 wherein said relative source light parameter is selected based on image percentiles.

8. A method as described in claim 2 wherein said rate control parameter is a variable that is dependent on current frame image content.

9. A method as described in claim 2 wherein said rate control parameter is a variable that is dependent on scene cut detection.

10. A method for modifying a display source light illumination level, said method comprising:

a) determining a relative source light parameter representing the relative amount that a source light level can be reduced with adequate compensation through brightness preservation processing of a current image frame;

b) analyzing current-frame image content of said current image frame;

c) determining a rate control parameter based on said current image frame content;

d) determining a display power target value;

e) determining actual display power value;

f) subtracting said actual display power value from said display power target value, thereby creating a power difference value;

g) multiplying said power difference value by said rate control parameter, thereby creating a power adjustment;

h) determining a previous frame peak source light illumination level;

i) adding said power adjustment to said previous frame peak source light illumination level, thereby creating a current frame peak source light illumination level;

j) ensuring that said current frame peak source light illumination level falls within an allowable range defined by a minimum limit and a maximum limit; and

k) multiplying said current frame peak source light illumination level by said relative source light parameter, thereby creating a modified source light illumination level.

11. A method as described in claim 10 wherein said display target power value is a source light illumination level target.

12. A method as described in claim 10 wherein said actual display power value is an actual source light illumination level.

13. A method as described in claim 10 wherein said display target power value is a power consumption target.

14. A method as described in claim 10 wherein said actual display power value is an actual battery power consumption value.

15. A method as described in claim 10 wherein said relative source light parameter is selected based on image percentiles.

16. A method as described in claim 10 wherein said rate control parameter is a variable that is dependent on scene cut detection.

17. A method as described in claim 16 wherein said rate control parameter has a value of 1 when a scene cut is detected in said current frame.

18. A method as described in claim 10 further comprising analyzing previous-frame image content for a previous frame.

19. A method as described in claim 18 wherein said determining a rate control parameter also comprises said analyzing previous frame image content.

20. A method as described in claim 19 wherein said analyzing current-frame image content and said analyzing previous-frame image content comprises scene cut detection.

21. A system for modifying a display source light illumination level, said system comprising:

a) a relative parameter receiver for receiving a relative source light parameter representing the relative amount that a source light level can be reduced with adequate compensation through brightness preservation processing;

b) a target receiver for receiving a display power target value;

c) a sensor for sensing an actual display power value;

d) a difference calculator for subtracting said actual display power value from said display power target value, thereby creating a power difference value;

e) a product calculator for multiplying said power difference value by a rate control parameter, thereby creating a power adjustment;

f) a buffer for storing a previous frame peak source light illumination level;

g) a sum calculator for adding said power adjustment to said previous frame peak source light illumination level, thereby creating a current frame peak source light illumination level;

h) a limit processor for ensuring that said current frame peak source light illumination level falls within an allowable range defined by a minimum limit and a maximum limit; and

i) a modified level calculator for multiplying said current frame peak source light illumination level by said relative source light parameter, thereby creating a modified source light illumination level.