Distributed processing for video enhancement and display power management

Abstract

In visual display devices such as LCD devices with backlight illumination, the backlight typically consumes most of device battery power. In the interest of displaying a given pixel pattern at a minimized backlight level, the pattern can be transformed while maintaining image quality, with a transform determined from pixel luminance statistics. Aside from, or in addition to being used for such minimizing, a transform also can be used for image enhancement, for a displayed image better to meet a visual perception quality. In either case, the transform preferably is constrained for enforcing one or several display attributes. In a network setting, the technique can be implemented in distributed fashion, so that subtasks of the technique are performed by different, interconnected processors such as server, client and proxy processors.

Description

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a graph showing an exemplary pixel value distribution along a line of 256 pixel values as may arise for a particular given pattern, and further showing the graphs of the identity transform and of an illustrative multi-stage transform.

FIG. 2 is a graph showing the pixel value distribution of FIG. 1 approximated by a step function, and further showing how the transform slopes are computed.

FIG. 3 is a graph showing a multi-stage transform obtained for the step function of FIG. 2.

FIG. 4 is a representation of an exemplary procedure for transforming the given pixel values using the pixel value distribution of the given pattern in accordance with a preferred embodiment of the invention.

FIG. 5 is a representation of a further exemplary procedure for transforming the given pixel values using the pixel value distribution of the given pattern, representing a further preferred embodiment of the invention.

FIG. 6 is a block schematic of an exemplary embodiment of the technique.

FIG. 7 is a block schematic of an exemplary distributed-processing embodiment of the technique.

FIG. 8 is a table of exemplary feasible allocations of processing tasks in distributed processing.

Claims

1. A computer method in determining a pixel display pattern from a pixel given pattern using a transform, comprising the steps of: (A) enhancing obtained input information into output information, thereby furthering progress towards: (a) for at least one display attribute, the transform meeting at least one constraint, and(b) for at least one substantially uniform background luminance value and subject to the at least one constraint, the transform being such that, if the pixel display pattern is displayed against the substantially uniform background, visual distortion as compared with the pixel given pattern is minimized; and(B) forwarding the output information for one of (i) further enhancement and (ii) display of the pixel display pattern.

2. The method of claim 1, wherein the pixel given pattern is one of a video sequence.

3. The method of claim 1, wherein the input information comprises luminance values of at least a portion of the pixels of the pixel given pattern.

4. The method of claim 1, wherein the input information comprises side information for furthering the progress.

5. The method of claim 4, wherein the side information comprises executable code.

6. The method of claim 4, wherein the side information comprises at least one backlight value which is suited for utilization for a substantially uniform background for the pixel display pattern.

7. The method of claim 6, wherein the side information comprises at least one parameter value functionally dependent on the at least one backlight value.

8. The method of claim 4, wherein the side information comprises at least a portion of histogram information of pixel-given-pattern luminance values.

9. The method of claim 8, wherein the histogram information comprises subsampled histogram information.

10. The method of claim 4, wherein the side information comprises at least a portion of the transform.

11. The method of claim 2, comprising utilizing the side information for processing a current video frame of a sequence of video frames.

12. The method of claim 11, wherein the side information is from the current video frame.

13. The method of claim 11, wherein the side information is from a preceding video frame.

14. The method of claim 13, wherein the preceding video frame is immediate predecessor to the current video frame.

15. The method of claim 1, wherein further enhancement in step (B) (i) comprises applying the transform to the pixel given pattern.

16. The display of the pixel display pattern of step (B) (ii) of claim 1.

17. The method of claim 1, effected by a server in a communications network functionally connecting the server with a client.

18. The method of claim 17, comprising at least one of: determining histogram information, determining backlight value information, determining transform information, and applying the transform.

19. The method of claim 1, effected by a client in a communications network functionally connecting the client with a server.

20. The method of claim 19, comprising setting the backlight value.

21. The method of claim 20, further comprising at least one of: determining histogram information, determining backlight value information, determining transform information, and applying the transform.

22. The method of claim 1, effected by a proxy in a communications network functionally connecting a server with a client.

23. The method of claim 22, comprising at least one of: determining histogram information, determining backlight value information, determining transform information, and applying the transform.

24. The method of claim 1, comprising embedded decoding of the pixel given pattern.

25. The method of claim 1, effected at least in part using vectorized processing.

26. The method of claim 1, wherein the transform comprises a DC-component transform.

27. The method of claim 1, wherein the pixel given pattern has chrominance, and the method comprises determining a factor for scaling the chrominance.

28. The method of claim 1, wherein the at least one constraint is for minimizing washout in a generated pixel-display-pattern image.

29. The method of claim 1, wherein the at least one constraint is for maintaining contrast in a generated pixel-display-pattern image.

30. The method of claim 1, comprising determining the transform from statistics of pixel-luminance-given values of the pixel given pattern.

31. The method of claim 30, wherein the statistics comprises histogram information.

32. The method of claim 1, wherein the substantially uniform background luminance value is prescribed.

33. The method of claim 1, comprising determining the substantially uniform background luminance value from information obtained from pixel-luminance-given values of the pixel given pattern.

34. The method of claim 33, wherein the information is obtained from a histogram of the pixel-luminance-given values.

35. The method of claim 1, comprising determining a minimized background luminance value.

36. The method of claim 35, comprising determining the minimized background luminance value using statistics of pixel-given-luminance values of the pixel given pattern.

37. The method of claim 33, comprising effecting step (A) (b) for a plurality of different background luminance values.

38. The method of claim 1, comprising determining the transform as a piecewise linear function.

39. The method of claim 38, wherein each of the linear pieces of the piecewise linear function spans at least one bin of a histogram of pixel-luminance-given values of the pixel given pattern.

40. The method of claim 38, wherein at least one of the linear pieces of the piecewise linear function has a slope which is determined from: local statistics of the pixel-luminance-given values in a histogram bin spanned by the at least one of the linear pieces, andglobal statistics over all histogram bins.

41. The method of claim 38, wherein the at least one constraint comprises a constraint on a slope of a linear piece of the piecewise linear function.

42. The method of claim 41, wherein the constraint is such that, at contiguous low pixel luminance values of the pixel given pattern, the slope is fixed.

43. The method of claim 41, wherein the constraint is such that, at contiguous high pixel luminance values of the pixel given pattern, the slope is fixed.

44. The method of claim 1, further comprising high-pass filtering of the pixel display pattern.

45. The method of claim 2, further comprising temporal low-pass filtering of sequential transformed display patterns.

46. The method of claim 1, comprising generating different uniform background luminance values for different pixel display patterns of a plurality of pixel given patterns of a video sequence.

47. The method of claim 1, wherein the input information comprises pixel-luminance-given values of the pixel given pattern, and at least one of: (i) video sequence history, (ii) LCD panel characteristics, and (iii) ambient light condition.

48. The method of claim 1, wherein the output information comprises the substantially uniform background luminance value.

49. The method of claim 1, further comprising displaying the pixel display pattern on a display device.

50. The method of claim 49, wherein displaying is against a background having the substantially uniform background luminance.

51. The method of claim 49, wherein displaying is against a background other than the background having the substantially uniform background luminance.

52. The method of claim 49, wherein displaying is against a background having a luminance which is chosen at a client processor.

53. The method of claim 49, wherein the display device is included in one of: a notebook-PC, a DVD playback device, a handheld consumer electronic device, a portable media player, a PDA device, an LCD TV and a mobile phone.

54. A processor instructed for collaborating for display of a pixel display pattern generated from a pixel given pattern using a transform, wherein instruction is for at least a portion of: (a) for at least one display attribute, determining at least one constraint on the transform;(b) for at least one substantially uniform background luminance value and subject to the at least one constraint, determining the transform such that, if the pixel display pattern is displayed against the substantially uniform background, visual distortion as compared with the pixel given pattern is minimized; and(c) applying the transform to the pixel given pattern.

55. A device for collaborating for display of a pixel display pattern generated from a pixel given pattern using a transform, made for at least a portion of effecting: (a) for at least one display attribute, determining at least one constraint on the transform;(b) for at least one substantially uniform background luminance value and subject to the at least one constraint, determining the transform such that, if the pixel display pattern is displayed against the substantially uniform background, visual distortion as compared with the pixel given pattern is minimized; and(c) applying the transform to the pixel given pattern.

56. A service for generating a pixel display pattern from a pixel given pattern using a transform, wherein (a) the transform is subject to at least one constraint for satisfying at least one display attribute;(b) for at least one substantially uniform background luminance value and subject to the at least one constraint, the transformation is determined such that, if the pixel display pattern is displayed against the substantially uniform background, visual distortion as compared with the pixel given pattern is minimized.