Methods and measurement engine for aligning multi-projector display systems

• US 20040085256A1
• Filed: 10/30/2002
• Published: 05/06/2004
• Est. Priority Date: 10/30/2002
• Status: Active Grant

• Current Assignee: U Chicago Argonne, LLC
• Original Assignee: University of Chicago
• Inventors: Stevens, Rick L., Judson, Ivan R., Hereld, Mark
• Granted Patent: US 7,019,713 B2
• Time in Patent Office: Days
• US Class Current: 345/1.1
• CPC Class Codes: H04N 9/12 Picture reproducers H04N9/11 takes precedence
• CPC Class Codes: H04N 9/3147 Multi-projection systems displays in general H04N9/12; video walls G06F3/1446, G09G2300/026
• CPC Class Codes: H04N 9/3185 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

Methods and a measurement engine are provided for aligning multi-projector display systems. An image pattern description is stored and tiled display test pattern images are captured. The stored image pattern description and at least one captured tiled display test pattern image are used to identify a tile array placement and layout; a tile registration measurement; and a dot grid measurement providing measured dot grid positions. At least one captured tiled display test pattern images and the measured dot grid positions are used for calculating tile-to-camera maps and a camera-to-mural map. The tile-to-camera maps and the camera-to-mural map are used to generate control and correction data.

Claims

1. A method for aligning multi-projector display systems comprising the steps of:

storing an image pattern description;

capturing tiled display test pattern images;

using said stored image pattern description and at least on said captured tiled display test pattern image, identifying a tile array placement and layout;

using said stored image pattern description and at least one said captured tiled display test pattern image, performing a tile registration measurement;

using said stored image pattern description, at least on said captured tiled display test pattern image, performing a dot grid measurement to provide measured dot grid positions;

using at least one said captured tiled display test pattern images and said measured dot grid positions, calculating a tile-to-camera map;

using at least one said captured tiled display test pattern images and said measured dot grid positions, calculating a camera-to-mural map; and

using said tile-to-camera map and said camera-to-mural map to generate control and correction data.

2. A method for aligning multi-projector display systems as recited in claim 1 wherein said stored image pattern description image describes first and second test pattern images;

said first test pattern image adapted for determining tile layout and said second test pattern image adapted for determining tile geometry.

3. A method for aligning multi-projector display systems as recited in claim 2 wherein said first test pattern image includes a generally centrally position large segment and a plurality of separate spaced apart registration marks.

4. A method for aligning multi-projector display systems as recited in claim 2 wherein said second test pattern image includes a generally uniform array of a plurality of dots.

5. A method for aligning multi-projector display systems as recited in claim 1 wherein the step of capturing tiled display test pattern images includes creating first and second test pattern images;

said first test pattern image adapted for determining tile layout and said second test pattern image adapted for determining tile geometry.

6. A method for aligning multi-projector display systems as recited in claim 5 includes creating ensemble test patterns using said first and second test pattern images.

7. A method for aligning multi-projector display systems as recited in claim 6 includes creating a first ensemble test pattern for displaying said first test pattern image onto each projector tile of a multi-projector display.

8. A method for aligning multi-projector display systems as recited in claim 7 includes creating at least one second ensemble test pattern for displaying said second test pattern image onto each projector tile of the multi-projector display.

9. A method for aligning multi-projector display systems as recited in claim 8 includes the step of using a digital camera and capturing a digital image of said displayed first ensemble test pattern and said displayed at least one second ensemble test pattern.

10. A method for aligning multi-projector display systems as recited in claim 1 wherein the step of identifying said tile array placement and layout includes binarizing one said captured tiled display test pattern image, identifying and measuring a plurality of segments of said binarized image, and sorting said plurality of segments to identify said tile array placement and layout.

11. A method for aligning multi-projector display systems as recited in claim 10 includes the step of identifying a predefined registration segment.

12. A method for aligning multi-projector display systems as recited in claim 11 wherein the step of performing said tile registration measurement includes the steps of identifying corners of said predefined registration segment;

estimating and measuring positions of a plurality of registration marks relative to said identified corners of said predefined registration segment.

13. A method for aligning multi-projector display systems as recited in claim 1 further includes the steps of measuring camera jitter and drift;

and applying correction based upon said measured camera jitter and drift to said dot grid measurement.

14. A method for aligning multi-projector display systems as recited in claim 1 wherein the step of performing said dot grid measurement to provide measured dot grid positions includes the steps of predicting positions of a plurality of dots in a displayed tile for each projector from said test image description;

measuring actual dot positions within said displayed tile for each projector;

measuring a spacing of said measured actual dot positions and comparing said measured spacing with an expected spacing from said predicted positions to provide an error metric.

15. A method for aligning multi-projector display systems as recited in claim 14 further includes minimizing an error metric by moving measurement to adjacent positions;

and rejecting all single measurements identified above a set spacing from predicted positions.

16. A method for aligning multi-projector display systems as recited in claim 1 wherein the step of calculating said tile-to-camera map includes computing a least-squares fit of both measured X and Y camera coordinates to a parameterized function.

17. A method for aligning multi-projector display systems as recited in claim 16 wherein the step of calculating said camera-to-mural map includes computing a least-squares fit of both measured X and Y camera coordinates to a parameterized function.

18. A method for aligning multi-projector display systems as recited in claim 17 wherein said parameterized function including a cubic function.

19. A method for aligning multi-projector display systems as recited in claim 1 wherein the step of using said tile-to-camera map and said camera-to-mural map to generate said control and correction data includes at least one of:

extracting two dimensional offsets from said tile-to-camera map and using said extracted two dimensional offsets to correct at least a portion of a measured misalignment;

extracting pose parameters for each projector from said tile-to-camera map and using said extracted pose parameters to correct at least a portion of a measured misalignment.

20. A measurement engine for aligning multi-projector display systems comprising:

a plurality of projectors for projecting a digital source image onto multi-projector display to form a composite image;

a respective positioner associated with each of said plurality of projectors;

a camera for capturing tiled display test pattern images;

a computer for storing an image pattern description;

said computer for performing the steps of;

using said stored image pattern description and at least on said captured tiled display test pattern image, identifying a tile array placement and layout;

using said stored image pattern description and at least one said captured tiled display test pattern image, performing a tile registration measurement;

using said stored image pattern description, at least on said captured tiled display test pattern image, performing a dot grid measurement to provide measured dot grid positions;

using at least one said captured tiled display test pattern images and said measured dot grid positions, calculating a tile-to-camera map;

using at least one said captured tiled display test pattern images and said measured dot grid positions, calculating a camera-to-mural map; and

using said tile-to-camera map and said camera-to-mural map to generate control and correction data.