Perspective correction for curved display screens

• US 10,366,476 B2
• Filed: 10/17/2017
• Issued: 07/30/2019
• Est. Priority Date: 03/10/2016
• Status: Active Grant

• Current Assignee: Netflix, Inc.
• Original Assignee: Netflix, Inc.
• Inventors: Russell, Michael
• Primary Examiner(s): Tsai, Tsung Yin
• Application Number:
  US15/786,495
• Publication Number:
  US 20180040112A1
• Time in Patent Office: 651 Days
• CPC Class Codes: G06T 2207/20048 Transform domain processing
• CPC Class Codes: G06T 5/80 Geometric correction
• CPC Class Codes: G06T 7/0002 Inspection of images, e.g. flaw detection
• CPC Class Codes: G09G 2320/0693 Calibration of display systems
• CPC Class Codes: G09G 3/001 using specific devices not provided for in groups G09G3/02 - G09G3/36, e.g. using an intermediate record carrier such as a film slide; Projection systems; Display of non-alphanumerical information, solely or in combination with alphanumerical information, e.g. digital display on projected diapositive as background slide projectors per se G03B23/00 = 42 HP
• CPC Class Codes: G09G 3/03 specially adapted for displays having non-planar surfaces, e.g. curved displays
• CPC Class Codes: H04N 17/00 Diagnosis, testing or measuring for television systems or their details
• CPC Class Codes: H04N 17/004 for digital television systems
• CPC Class Codes: H04N 9/31 Projection devices for colour picture display , e.g. using electronic spatial light modulators [ESLM]
• 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

One embodiment of the present invention sets forth a technique for performing perspective correction on one or more test images. The technique includes analyzing a first test image to detect a set of outer points and calculating a geometric plane equation based on the set of outer points. The technique further includes projecting a first set of points associated with a first curved screen model based on the geometric plane equation to generate a second set of points. The technique further includes comparing the second set of points to a set of inner points included in the first test image to determine at least one error value, and determining a screen curvature value based on the at least one error value.

Claims

1. A non-transitory computer-readable storage medium including instructions that, when executed by a processor, cause the processor to perform the steps of:

calculating a plane equation based on a first set of points associated with a first test image;

generating a first curved screen model based on a first screen curvature value;

projecting a second set of points onto the first curved screen model based on the plane equation to generate a third set of points;

comparing the third set of points to the first test image to determine an error value; and

determining a final screen curvature value based on the error value.

2. The non-transitory computer-readable storage medium of claim 1, further comprising transforming a sequence of calibration images based on the final screen curvature value to generate a sequence of transformed images.

3. The non-transitory computer-readable storage medium of claim 2, further comprising performing one or more calibration procedures based on the sequence of transformed images.

4. The non-transitory computer-readable storage medium of claim 1, wherein comparing the third set of points to the test image, comprises, for each point included in the third set of points, calculating a distance to a corresponding point included in the test image to determine an individual error value, and further comprising determining the error value based on the individual error values.

5. The non-transitory computer-readable storage medium of claim 1, further comprising:

generating a second curved screen model based on a second screen curvature value;

projecting a fifth set of points onto the second curved screen model based on the geometric plane equation to generate a sixth set of points; and

comparing the sixth set of points to the first test image to determine a second error value.

6. The non-transitory computer-readable storage medium of claim 5, further comprising:

generating a third curved screen model based on a third screen curvature value;

projecting a seventh set of points onto the third curved screen model based on the geometric plane equation to generate an eighth set of points;

comparing the eighth set of points to the first test image to determine a third error value.

7. The non-transitory computer-readable storage medium of claim 6, wherein determining the final screen curvature value comprises:

comparing the first error value, the second error value, and the third error value to determine a lowest error value; and

selecting a screen curvature value associated with the lowest error value to be the final screen curvature value.

8. The non-transitory computer-readable storage medium of claim 7, further comprising transforming at least one image based on the final screen curvature value to generate a transformed image.

9. The non-transitory computer-readable storage medium of claim 1, wherein the test image comprises a checkerboard pattern displayed on a curved display screen.

10. The non-transitory computer-readable storage medium of claim 9, wherein the first set of points comprises at least three outer points of the checkerboard pattern, and the fourth set of points comprises a plurality of inner points of the checkerboard pattern.

11. A method, comprising:

calculating a plane equation based on a first set of points associated with a first test image;

generating a first curved screen model based on a first screen curvature value;

projecting a second set of points onto the first curved screen model based on the plane equation to generate a third set of points; and

determining a final screen curvature value based on the third set of points and the first test image.

12. The method of claim 11, further comprising transforming a sequence of calibration images based on the final screen curvature value to generate a sequence of transformed images.

13. The method of claim 12, further comprising performing one or more calibration procedures based on the sequence of transformed images.

14. The method of claim 11, further comprising comparing the third set of points to the first test image to determine an error value, wherein comparing the third set of points to the test image, comprises, for each point included in the third set of points, calculating a distance to a corresponding point included in the test image to determine an individual error value, and further comprising determining the error value based on the individual error values.

15. The method of claim 11, further comprising:

comparing the third set of points to the first test image to determine a first error value;

generating a second curved screen model based on a second screen curvature value;

projecting a fifth set of points onto the second curved screen model based on the geometric plane equation to generate a sixth set of points; and

comparing the sixth set of points to the first test image to determine a second error value.

16. The method of claim 15, further comprising:

generating a third curved screen model based on a third screen curvature value;

projecting a seventh set of points onto the third curved screen model based on the geometric plane equation to generate an eighth set of points;

comparing the eighth set of points to the first test image to determine a third error value.

17. The method of claim 16, wherein determining the final screen curvature value comprises:

comparing the first error value, the second error value, and the third error value to determine a lowest error value; and

selecting a screen curvature value associated with the lowest error value to be the final screen curvature value.

18. The method of claim 17, further comprising transforming at least one image based on the final screen curvature value to generate a transformed image.

19. The method of claim 11, wherein the test image comprises a checkerboard pattern displayed on a curved display screen.

20. The method of claim 19, wherein the first set of points comprises at least three outer points of the checkerboard pattern, and the fourth set of points comprises a plurality of inner points of the checkerboard pattern.

21. A computing device, comprising:

a memory storing a perspective correction application; and

a processor that is coupled to the memory and, when executing the perspective correction application, is configured to;

calculate a transformation matrix based on a first test image;

project a first set of points onto a first curved screen model based on the transformation matrix to generate a second set of points; and

determine a final screen curvature value based on the second set of points and the first test image.

22. The computing device of claim 21, wherein the processor is further configured to transform a sequence of calibration images based on the final screen curvature value to generate a sequence of transformed images.