System and method for automated calibration and correction of display geometry and color

• US 8,406,562 B2
• Filed: 08/08/2007
• Issued: 03/26/2013
• Est. Priority Date: 08/11/2006
• Status: Active Grant

• Current Assignee: Geo Semiconductor Incorporated
• Original Assignee: Geo Semiconductor Incorporated
• Inventors: Bassi, Zorawar, Vakili, Masoud
• Primary Examiner(s): Allison, Andrae S
• Application Number:
  US11/835,686
• Publication Number:
  US 20080062164A1
• Time in Patent Office: 2,057 Days
• Field of Search: 348/231.3, 348/231.6, 348/333.11, 348/333.12, 348/222.1, 348/241, 348/250, 382/276, 382/293, 382/294, 382/295, 382/296, 382/298, 382/299, 382/284, 382/300
• US Class Current: 382/275
• CPC Class Codes: G06T 7/80 Analysis of captured images to determine intrinsic or extrinsic camera parameters, i.e. camera calibration
• CPC Class Codes: H04N 9/3147 Multi-projection systems displays in general H04N9/12; video walls G06F3/1446, G09G2300/026
• CPC Class Codes: H04N 9/3182 Colour adjustment, e.g. white balance, shading or gamut white balance per se H04N9/73; control of amplitude of colour signals H04N9/68; colour control circuits for displays in general G09G5/02, G09G3/2003, G09G3/3607
• CPC Class Codes: H04N 9/3185 Geometric adjustment, e.g. keystone or convergence optical or mechanical adjustment of convergence H04N9/317; using scanning means H04N3/22; optical or mechanical adjustments of projectors not peculiar to the presence of an electronic spatial light modulator G03B21/14
• CPC Class Codes: H04N 9/3194 including sensor feedback

Abstract

Various embodiments are described herein for a system and method for calibrating a display device to eliminate distortions due to various components such as one or more of lenses, mirrors, projection geometry, lateral chromatic aberration and color misalignment, and color and brightness non-uniformity. Calibration for distortions that vary over time is also addressed. Sensing devices coupled to processors can be used to sense display characteristics, which are then used to compute distortion data, and generate pre-compensating maps to correct for display distortions.

Claims

1. A display calibration system for use with a display device having a viewing surface, said display calibration system comprising:

at least one sensing device, placed at a position relative to the display device, to sense information about at least one of shape, size, boundary, and orientation of the viewing surface, wherein the at least one sensing device is further configured to sense a plurality of test images displayed on the viewing surface;

at least one processor coupled to said at least one sensing device, to compute display device characterizations and display distortions based on the sensed information and the sensed test images, including a distortion component due to positioning of the at least one sensing device;

wherein the at least one processor is further configured to generate pre-compensating maps based on the display distortions, such that when said pre-compensating maps are applied to input image data prior to display, a resulting displayed image on the viewing surface is substantially distortion free.

2. The display calibration system of claim 1, wherein the display distortions vary in time, and wherein the display calibration system is configured to dynamically calibrate the display device to pre-compensate for varying distortions.

3. The display calibration system of claim 1, wherein the at least one processor is further configured for correcting for at least one of an overflow condition wherein a displayed image is larger than the viewing surface, an underflow condition wherein the displayed image is smaller than the viewing surface, and a mismatch condition wherein parts of the displayed image overflow the viewing surface and other parts of the displayed image underflow the viewing surface.

4. The display calibration system of claim 1, wherein the display device is a rear projection display device having a housing, and wherein the display calibration system is disposed inside the housing.

5. The display calibration system of claim 1, wherein the at least one sensing device is further configured to sense at least one of luminance information and color information, and wherein said at least one processor is accordingly configured to respectively pre-compensate for at least one of luminance non-uniformity and color non-uniformity.

6. The display calibration system of claim 1, wherein the display system further comprises optical components having additional distortions, and wherein the at least one processor is further configured to concatenate the additional distortions with the display distortions to pre-compensate for both the additional distortions and the display distortions.

7. The display calibration system of claim 1, wherein the display distortions include at least one of geometric distortions, optical distortions, misconvergence, misalignment, and lateral chromatic aberrations.

8. The display calibration system of claim 1, wherein the at least one sensing device is configured to sense distances to a plurality of points on the viewing surface, and wherein the at least one processor is configured to compute relative position and relative orientation of the viewing surface based on the distances.

9. The display calibration system of claim 1, wherein the at least one sensing device is configured to sense different portions of a test image on the viewing surface at various focal distances and wherein the at least one processor is configured to determine highest contrast in different portions of the test image and to compute distances to different portions of the viewing surface based on the determined highest contrast to compute the shape and relative orientation of the viewing surface.

10. The display calibration system of claim 1, wherein the at least one sensing device has sensor distortions, and wherein the at least one processor is further configured to compute the sensor distortions and to account for the sensor distortions when computing the display distortions.

11. The display calibration system of claim 10, wherein the sensor distortions are caused by the at least one sensing device having an axis which is not parallel to a normal direction of the viewing surface.

12. The display calibration system of claim 1, wherein the at least one image sensing device comprises a plurality of image sensing devices disposed at different positions known by the at least one processor, and wherein said at least one processor is configured to compare different sensed test images from different sensing devices and compute the display distortions based on the different sensed images and position of the different sensing devices.

13. The display calibration system of claim 1, wherein the at least one image sensing device is configured to sense information about a test image having four markers on the viewing surface, and wherein the at least one processor is adapted to compute keystone distortion based on the sensed information.

14. The display calibration system of claim 1, wherein the at least one sensing device is further configured to sense at least one of luminance information and color information, and wherein the at least one processor is further configured to correct for at least one of luminance non-uniformity and color non-uniformity caused by the pre-compensating maps.

15. The display calibration system of claim 1, wherein the pre-compensating maps are implemented by surface functions.

16. The display calibration system of claim 15, wherein the surface functions are polynomials.

17. The display calibration system of claim 15, wherein the at least one processor is further configured to adjust the surface functions to further compensate for at least one of an overscan condition and an underscan condition.

18. The display calibration system of claim 1, wherein the at least one processor is further configured to concatenate various display distortions and to generate surface functions that pre-compensate for the concatenated distortions.

19. The display calibration system of claim 1, wherein the at least one processor is configured to compute the display distortions by partitioning the viewing surface into patches according to the severity of the display distortions in each patch, and generating pre-compensating maps for the display distortions in each patch.

20. A display calibration method for a display device having a viewing surface, said display calibration method comprising:

placing at least one sensing device at a position relative to the display device;

sensing information about at least one of shape, size, boundary, and orientation of the viewing surface using the at least one sensing device;

sensing a plurality of test images displayed on the viewing surface using the at least one sensing device;

computing display device characterizations, display distortions and a distortion component due to positioning of the at least one sensing device, based on the sensed information and the sensed test images using at least one processor coupled to said at least one sensing device;

wherein pre-compensating maps are generated based on the display distortions by the at least one processor, such that when said pre-compensating maps are applied to input image data prior to display, a resulting displayed image on the viewing surface is substantially distortion free.

21. The display calibration method of claim 20, wherein the display distortions vary in time, and wherein said method dynamically calibrates the display device to pre-compensate for varying distortions.

22. The display calibration method of claim 20, wherein said method corrects at least one of an overflow condition wherein a displayed image is larger than the viewing surface, an underflow condition wherein the displayed image is smaller than the viewing surface, and a mismatch condition wherein parts of the displayed image overflow the viewing surface and other parts of the displayed image underflow the viewing surface.

23. The display calibration method of claim 20, wherein the display device is a in rear projection system.

24. The display calibration method of claim 20, wherein the at least one sensing device is further configured to sense at least one of luminance information and color information, and wherein said at least one processor is further configured to respectively pre-compensate for at least one of luminance non-uniformity and color non-uniformity.

25. The display calibration method of claim 20, wherein said method also corrects for additional distortions caused by optical components, by concatenating the additional distortions with the display distortions to pre-compensate for both the additional distortions and the display distortions.

26. The display calibration method of claim 20, wherein the display distortions include at least one of geometric distortions, optical distortions, misconvergence, misalignment, and lateral chromatic aberrations.

27. The display calibration method of claim 20, wherein the at least one sensing device is configured to sense distances to a plurality of points on the viewing surface, and wherein the at least one processor is configured to compute relative position and relative orientation of the viewing surface based on the distances.

28. The display calibration method of claim 20, wherein the at least one sensing device is configured to sense different portions of a test image on the viewing surface at various focal distances and wherein the at least one processor is configured to determine highest contrast in different portions of the test image and to compute distances to different portions of the viewing surface based on the determined highest contrast to compute the shape and relative orientation of the viewing surface.

29. The display calibration method of claim 20, wherein the at least one sensing device has sensor distortions, and wherein the at least one processor is further configured to compute the sensor distortions and to account for the sensor distortions when computing the display distortions.

30. The display calibration method of claim 29, wherein the sensor distortions are caused by the at least one sensing device having an axis which is not parallel to a normal direction of the viewing surface.

31. The display calibration method of claim 20, wherein the at least one image sensing device comprises a plurality of image sensing devices disposed at different positions known by the at least one processor, and wherein said at least one processor is configured to compare different sensed test images from different sensing devices and compute the display distortions based on the different sensed images and position of the different sensing devices.

32. The display calibration method of claim 20, wherein the at least one image sensing device is configured to sense information about a test image having four markers on the viewing surface, and wherein the at least one processor is configured to compute keystone distortion based on the sensed information.

33. The display calibration method of claim 20, wherein the at least one sensing device is further configured to sense at least one of luminance information and color information, and wherein the at least one processor is further configured to correct for at least one of luminance non-uniformity and color non-uniformity caused by the pre-compensating maps.

34. The display calibration method of claim 20, wherein the pre-compensating maps are implemented by surface functions.

35. The display calibration method of claim 34, wherein the surface functions are polynomials.

36. The method of claim 34, wherein the at least one processor is further configured to adjust the surface functions to further compensate for at least one of an overscan condition and an underscan condition.

37. The display calibration method of claim 20, wherein the at least one processor is further configured to concatenate various display distortions and to generate surface functions that pre-compensate for the concatenated distortions.

38. The display calibration method of claim 20, wherein the at least one processor is configured to compute the display distortions by partitioning the viewing surface into patches according to the severity of the display distortions in each patch, and generating pre-compensating maps for the display distortions in each patch.