SYSTEM AND METHOD FOR AUTOMATED CALIBRATION AND CORRECTION OF DISPLAY GEOMETRY AND COLOR

• US 20080062164A1
• Filed: 08/08/2007
• Published: 03/13/2008
• Est. Priority Date: 08/11/2006
• Status: Active Grant

• Current Assignee: Geo Semiconductor Incorporated
• Original Assignee: Geo Semiconductor Incorporated
• Inventors: VAKILI, Masoud, BASSI, Zorawar
• Granted Patent: US 8,406,562 B2
• Time in Patent Office: Days
• US Class Current: 345/214
• 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 adapted to sense information about at least one of shape, size, boundary, and orientation of the viewing surface, and,

at least one processor coupled to said at least one sensing device and being adapted to compute display device characterizations based on the sensed information by the at least one sensing device.

2. The display calibration system of claim 1, wherein the at least one sensing device is further adapted to sense test images displayed on the viewing surface and wherein said at least one processor is further adapted to compute display distortions based on the sensed test images and the display device characterizations.

3. The display calibration system of claim 2, wherein the at least one processor is further adapted 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.

4. The display calibration system of claim 3, wherein the display distortions vary in time, and wherein the display calibration system is adapted to dynamically calibrate the display device to pre-compensate for varying distortions.

5. The display calibration system of claim 3, wherein the at least one processor is adapted 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.

6. The display calibration system of claim 3, wherein the display device is a rear projection display device having a housing, and wherein the display calibration system is disposed inside the housing.

7. The display calibration system of claim 3, wherein the at least one sensing device is further adapted to sense at least one of luminance information and color information, and wherein said at least one processor is further adapted to respectively pre-compensate for at least one of luminance non-uniformity and color non-uniformity.

8. The display calibration system of claim 3, wherein the display system also comprises optical components having additional distortions, and wherein the at least one processor is further adapted to concatenate the additional distortions with the display distortions to pre-compensate for both the additional distortions and the display distortions.

9. The display calibration system of claim 2, wherein the display distortions include at least one of geometric distortions, optical distortions, misconvergence, misalignment, and lateral chromatic aberrations.

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

11. The display calibration system of claim 2, wherein the at least one sensing device is adapted to sense different portions of a test image on the viewing surface at various focal distances and wherein the at least one processor is adapted 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.

12. The display calibration system of claim 2, wherein the at least one sensing device has sensor distortions, and wherein the at least one processor is further adapted to compute the sensor distortions and to account for the sensor distortions when computing the display distortions.

13. The display calibration system of claim 12, 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.

14. The display calibration system of claim 2, 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 adapted 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.

15. The display calibration system of claim 2, wherein the at least one image sensing device is adapted 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.

16. The display calibration system of claim 3, wherein the at least one sensing device is further adapted to sense at lease one of luminance information and color information, and wherein the at least one processor is further adapted to correct for at least one of luminance nun-uniformity and color non-uniformity caused by the pre-compensating maps.

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

at least one sensing device adapted to sense information from test images displayed on the viewing surface; and

,

at least one processor coupled to said at least one sensing device, said at least one processor being adapted to compute display distortions based on the sensed information and generate pre-compensating maps to compensate for the display distortions, the pre-compensating maps being implemented by surface functions, 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.

18. The display calibration system of claim 17, wherein the at least one processor is further adapted to concatenate various distortions and to generate surface functions that pre-compensate for the concatenated distortions.

19. The display calibration system of claim 17, wherein the surface functions are polynomials.

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

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

at least one image sensing device adapted to sense information from test images displayed on the viewing surface, and,

at least one processor coupled to said at least one image sensing device, said at least one processor being adapted to compute display distortions based on the sensed information, partition the viewing surface into patches according to the severity of the display distortions in each patch, and generate pre-compensating maps for the display distortions in each patch, 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.

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

at least one image sensing device adapted to sense color information from test images displayed on the viewing surface for at least one color component independently, and,

at least one processor coupled to said at least one image sensing device, said at least one processor being adapted to compute color non-uniformity based on the sensed color information and to generate at least one color correction map for the at least one color component, such that when said at least one color correction map is applied to input image data prior to display, a resulting displayed image on the viewing surface is substantially free of at least one color non-uniformity.

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

at least one image sensing device adapted to sense information from individual color component test images displayed on the viewing surface, and,

at least one processor coupled to said at least one image sensing device and the display device, said at least one processor being adapted to compute geometric display distortions for at least one color component independently based on the sensed information and to generate at least one pre-compensating map for the at least one color component independently, such that when said at least one color correction map is applied to input image data prior to display, a resulting displayed image on the viewing surface is substantially free of at least one color-dependent geometric distortion.

24. A display calibration method for use in a projection system with a curved viewing surface, wherein said method comprises:

using multiple projectors to project different portions of an image onto a corresponding portion of the curved viewing surface; and

focusing substantially each portion of the image on the corresponding portion of the curved viewing surface to form the image in its entirety on the curved viewing surface with optimized focus.

25. The method of claim 24, wherein the method further comprises positioning and orienting each of the plurality of projectors independently such that a projection axis of each projector is substantially normal to the corresponding portion of the curved viewing surface to optimize focus and minimize geometric distortions.

26. A display calibration method for use in a projection system with a curved viewing surface, wherein said method comprises:

measuring a plurality of distances from the curved viewing surface to a focal plane of the projected image; and

shifting the focal plane until a function of the plurality of distances is minimized to obtain optimized focus.