Methods and systems for display-mode-dependent brightness preservation

• US 20060119613A1
• Filed: 12/02/2005
• Published: 06/08/2006
• Est. Priority Date: 12/02/2004
• Status: Active Grant

• 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
• Granted Patent: US 8,947,465 B2
• Time in Patent Office: Days
• US Class Current: 345/590
• 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 mode-dependent adjustment of image code values, said method comprising:

a) detecting a display mode; and

b) adjusting the code values of image pixels when said display mode meets a criterion.

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

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

4. A method as described in claim 1 wherein said adjusting 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.

5. A method as described in claim 1 wherein said adjusting 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.

6. A method as described in claim 3 wherein said gain map function is dependent on at least one of a display gamma, an efficiency factor and a maximum fidelity point (MFP).

7. A method as described in claim 4 wherein said roll-off curve begins at the value of said gain map function at said MFP and ends at a point that maps the maximum code value to the maximum display level.

8. A method as described in claim 4 wherein said roll-off curve matches the slope of said gain adjustment at said MFP point.

9. A method as described in claim 4 wherein said roll-off curve has a slope of zero at said end point.

10. A method as described in claim 1 wherein said adjusting 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 factor function to no gain at a maximum value point.

11. A method as described in claim 1 wherein said gain function is related to the slope of the tone scale adjustment model.

12. A method as described in claim 1 wherein said adjustment 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.

13. A method as described in claim 1 wherein said gain function is proportional to the ratio of the slope of the 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 mode-dependent adjustment of image code values, said method comprising:

a) applying a first tone scale adjustment model when a display mode meets a first criterion; and

b) applying a second tone scale adjustment model when said display mode does not meet said first criterion.

15. A 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 mode-dependent adjustment of image code values, said apparatus comprising:

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

b) a processor for applying said tone scale adjustment model to said image code values; and

c) a mode-dependent adjustment controller for selectively applying said tone scale adjustment model with said processor when a display mode matches a criterion.

17. An apparatus as described in claim 16 further comprising a display.

18. An apparatus as described in claim 16 further comprising a display mode detector.

19. An apparatus as described in claim 16 wherein said adjusting 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.

20. An apparatus as described in claim 16 wherein said adjusting 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.

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

a) detecting a display mode;

b) adjusting a display light source when said display mode meets a criterion; and

c) adjusting the code values of image pixels to compensate for said light source adjustment when said display mode meets said criterion.

22. A method as described in claim 21 wherein said adjusting comprises applying a tone scale adjustment model.

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

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

b) a tone scale processor for applying said tone scale adjustment model to said image code values;

c) a display light source;

d) a display light source adjustment model;

e) a light source processor for applying said display light source adjustment model and

f) a mode-dependent adjustment controller for selectively applying said tone scale adjustment model with said tone scale processor and for selectively applying said display light source adjustment model with said light source processor when a display mode matches a criterion.

24. An apparatus as described in claim 23 further comprising a display.