Methods and systems for display-mode-dependent brightness preservation

• US 8,947,465 B2
• Filed: 12/02/2005
• Issued: 02/03/2015
• Est. Priority Date: 12/02/2004
• Status: Expired due to Fees

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Laboratories of America Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Kerofsky, Louis Joseph
• Primary Examiner(s): WANG, JIN CHENG
• Application Number:
  US11/293,066
• Publication Number:
  US 20060119613A1
• Time in Patent Office: 3,350 Days
• Field of Search: 345/590, 345/102, 345/89, 345/211, 345/690, 382/167, 382260-274
• US Class Current: 345/690
• 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 2320/0276 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 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2320/0653 Controlling or limiting the speed of brightness adjustment of the illumination source
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/22 using controlled light sources
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336

Abstract

Embodiments of the present invention comprise systems, methods and devices for display-mode-dependent adjustment of image code values.

Claims

1. A method for display mode-dependent adjustment of image code values, said method comprising:

detecting a display mode for a display, wherein said display comprises a display source light and a plurality of light valves modulated to form a display image based on image code values of an input image and wherein said display mode relates to a source light illumination level for said display source light;

adjusting said source light to said source light illumination level corresponding to said display mode when said display mode meets a criterion; and

adjusting code values in an input image to be displayed on said display using said display mode and said source light illumination level such that said adjusting code values compensates for said adjusting said source light to said source light illumination level when said display mode meets said criterion.

2. The method as described in claim 1 wherein said adjusting code values comprises applying a tone scale adjustment model.

3. The method as described in claim 2 wherein said adjusting code values is proportional to the ratio of the slope of the tone scale adjustment model at a point below an MFP and the slope of the tone scale adjustment model at a specific code value.

4. The method as described in claim 1 wherein said adjusting code values comprises applying a gain map function to said code values.

5. The method as described in claim 4 wherein said gain map function is dependent on at least one of a display gamma, an efficiency factor and a maximum fidelity point (MFP).

6. The method as described in claim 1 wherein said adjusting code values comprises applying a constant gain multiplier to a first range of code values and applying a roll-off curve to a second range of code values.

7. The method as described in claim 6 wherein said roll-off curve begins at a value of said constant gain multiplier at an MFP and ends at a point that maps a maximum code value to a maximum display level.

8. The method as described in claim 6 wherein said roll-off curve matches the slope of said constant gain multiplier at an MFP point.

9. The method as described in claim 6 wherein said roll-off curve has a slope of zero at an end point.

10. The method as described in claim 1 wherein said adjusting code values comprises applying a gain adjustment to a range of code values below a maximum fidelity point (MFP) and applying a roll-off curve map to code values above said MFP point.

11. The method as described in claim 1 wherein said adjusting code values comprises adjusting the code values of a first group of image pixels to increase the perceived brightness of said pixels by applying a gain map function;

and adjusting the code values of a second group of image pixels according to a transition function that transitions from said gain map function to no gain at a maximum value point.

12. The method as described in claim 1 wherein said adjusting code values is related to a slope of a tone scale adjustment model.

13. The method as described in claim 1 wherein said adjusting code values is proportional to the ratio of the slope of a tone scale adjustment model at a point below an FTP and the slope of the tone scale adjustment model at a specific code value.

14. A method for display mode-dependent adjustment of image code values, said method comprising:

detecting a display mode for a display, wherein said display comprises a display source light and a plurality of light valves modulated to form a display image based on image code values of an input image and wherein said display mode relates to a source light illumination level for said display source light;

adjusting said source light to a first source light illumination level corresponding to said display mode when said display mode meets a first criterion;

applying a first tone scale adjustment model to code values of an input image to compensate for said adjusting said source light to said first source light illumination level when said display mode meets a first criterion; and

adjusting said source light to a second source light illumination level corresponding to said display mode when said display mode meets a second criterion; and

applying a second tone scale adjustment model to code values of said input image to compensate for said adjusting said to said second source light illumination level when said display mode meets said second criterion.

15. The method as described in claim 14 wherein said second tone scale adjustment model is a partial application of said first tone scale adjustment model.

16. An apparatus for display-mode-dependent adjustment of image code values, said apparatus comprising:

a display, wherein said display comprises a display source light and a plurality of light valves modulated to form a display image based on image code values of an input image and wherein said display comprises a plurality of display modes related to source light illumination levels for said display source light

a detector for detecting a current display mode for said display;

a source light adjuster for adjusting said source light to a source light illumination level corresponding to said current display mode when said current display mode meets a criterion;

a tone scale adjustment model for adjusting image code values; and

an image adjuster for adjusting code values in an input image to be displayed on said display using said current display mode and said source light illumination level such that said adjusting code values compensates for said adjusting said source light to said source light illumination level when said current display mode meets said criterion and wherein said adjusting code values comprises applying said tone scale adjustment model.

17. The apparatus as described in claim 16 wherein said adjusting code values with said tone scale adjustment model comprises applying a constant gain multiplier to a first range of code values and applying a roll-off curve to a second range of code values.

18. The apparatus as described in claim 16 wherein said adjusting code values with said tone scale adjustment model comprises applying a gain adjustment to a range of code values below an MFP point and applying a roll-off curve map to code values above said MFP point.

19. A method for display-mode-dependent, coordinated adjustment of image code values and a display source light, said method comprising:

detecting a display mode for a display, wherein said display comprises a display source light and a plurality of light valves modulated to form a display image based on image code values of an input image and wherein said display mode relates an input image content type and a corresponding source light illumination level for said display source light;

adjusting said source light to said source light illumination level corresponding to said display mode when said display mode meets a criterion; and

adjusting code values in an input image to be displayed on said display using said display mode and said source light illumination level such that said adjusting code values compensates for said adjusting said source light to said source light illumination level by increasing code value brightness when said source light illumination level decreases, said adjusting code values occurring when said display mode meets said criterion.

20. The method as described in claim 19 wherein said adjusting code values comprises applying a tone scale adjustment model.

21. An apparatus for display mode-dependent, coordinated adjustment of image code values and a display source light illumination level, said apparatus comprising:

a display, wherein said display comprises a display source light and a plurality of light valves modulated to form a display image based on image code values of an input image and wherein said display employs a plurality of display modes related to input image content types and corresponding source light illumination levels for said display source light;

a detector for detecting a current display mode for said display;

a source light adjuster for adjusting said source light to a source light illumination level corresponding to said current display mode when said current display mode meets a criterion;

a tone scale adjustment model for adjusting image code values; and

an image adjuster for adjusting code values in an input image to be displayed on said display using said current display mode and said source light illumination level such that said adjusting code values compensates for said adjusting said source light to said source light illumination level by increasing code value brightness when said source ht illumination level decreases said adjusting code values occurring when said current display mode meets said criterion and wherein said adjusting code values comprises applying said tone scale adjustment model.