Automatic Detection and Mapping of Symmetries in an Image

• US 20080247660A1
• Filed: 04/05/2007
• Published: 10/09/2008
• Est. Priority Date: 04/05/2007
• Status: Active Grant

• Current Assignee: Adobe Systems Incorporated (Adobe Inc.)
• Original Assignee: Adobe Systems Incorporated (Adobe Inc.)
• Inventors: Brandt, Jonathan, Zhang, Hui
• Granted Patent: US 8,494,297 B2
• Time in Patent Office: Days
• US Class Current: 382/254
• CPC Class Codes: G06V 10/42 Global feature extraction by analysis of the whole pattern, e.g. using frequency domain transformations or autocorrelation

Abstract

A method, system, and computer-readable storage medium are disclosed for determining one or more symmetries in an image comprising a plurality of pixels. A symmetry value may be automatically determined for each of the plurality of pixels. The symmetry value may indicate the strength of one or more symmetries in the image for the respective pixel. The symmetry value may be stored for each of the pixels.

Claims

1. A computer-implemented method for determining one or more symmetries in an image comprising a plurality of pixels, comprising:

automatically determining a symmetry value for each of the plurality of pixels, wherein the symmetry value indicates a strength of one or more symmetries in the image for the respective pixel; and

storing the symmetry value for each of the pixels.

2. The method as recited in claim 1, wherein automatically determining the symmetry value for each of the plurality of pixels in the image comprises:

determining one or more interest points in the image;

determining a matching symmetric interest point for each interest point, wherein each interest point and matching symmetric interest point comprise a matching interest point pair; and

voting for an axis of symmetry for each matching interest point pair.

3. The method as recited in claim 2, wherein automatically determining the symmetry value for each of the plurality of pixels in the image further comprises:

determining a symmetric pixel for each axis of symmetry for each of the plurality of pixels;

determining a photometric distortion between an area around each of the plurality of pixels and an area around the corresponding symmetric pixel;

removing the photometric distortion for each of the plurality of pixels;

determining a difference between the area around each of the plurality of pixels and the area around the corresponding symmetric pixel; and

normalizing the difference between the area around each of the plurality of pixels and the area around the corresponding symmetric pixel.

4. The method as recited in claim 1, further comprising:

segmenting the image based on the symmetry values.

5. The method as recited in claim 1, further comprising:

annotating the image based on the symmetry values.

6. The method as recited in claim 1, further comprising:

determining one or more image primitives in the image based on the symmetry values.

7. The method as recited in claim 1, wherein the one or more symmetries comprise a bilateral symmetry in at least a portion of the image.

8. The method as recited in claim 1, wherein the one or more symmetries comprise a radial symmetry in at least a portion of the image.

9. The method as recited in claim 1, wherein the one or more symmetries comprise a periodic pattern in at least a portion of the image.

10. The method as recited in claim 1, wherein automatically determining the symmetry value for each of the plurality of pixels in the image comprises:

determining one or more axes of symmetry in the image;

determining one or more axes of symmetry in a down-sampled version of the image;

determining one or more axes of symmetry in an up-sampled version of the image; and

combining the one or more axes of symmetry in the image, the one or more axes of symmetry in the down-sampled version of the image, and the one or more axes of symmetry in the up-sampled version of the image.

11. The method as recited in claim 1, wherein automatically determining the symmetry value for each of the plurality of pixels in the image comprises automatically determining the symmetry value for each of the plurality of pixels in the image at a plurality of resolutions.

12. A computer-readable storage medium, comprising program instructions, wherein the program instructions are computer-executable to implement:

determining a symmetry value for each of a plurality of pixels in an image, wherein the symmetry value indicates a strength of one or more symmetries in the image for the respective pixel; and

storing the symmetry value for each of the pixels.

13. The computer-readable storage medium as recited in claim 12, wherein automatically determining the symmetry value for each of the plurality of pixels in the image comprises:

determining one or more interest points in the image;

determining a matching symmetric interest point for each interest point, wherein each interest point and matching symmetric interest point comprise a matching interest point pair; and

voting for an axis of symmetry for each matching interest point pair.

14. The computer-readable storage medium as recited in claim 13, wherein automatically determining the symmetry value for each of the plurality of pixels in the image further comprises:

determining a symmetric pixel for each axis of symmetry for each of the plurality of pixels;

determining a photometric distortion between an area around each of the plurality of pixels and an area around the corresponding symmetric pixel;

removing the photometric distortion for each of the plurality of pixels;

determining a difference between the area around each of the plurality of pixels and the area around the corresponding symmetric pixel; and

normalizing the difference between the area around each of the plurality of pixels and the area around the corresponding symmetric pixel.

15. The computer-readable storage medium as recited in claim 12, wherein the program instructions are further computer-executable to implement:

segmenting the image based on the symmetry values.

16. The computer-readable storage medium as recited in claim 12, wherein the program instructions are further computer-executable to implement:

annotating the image based on the symmetry values.

17. The computer-readable storage medium as recited in claim 12, wherein the program instructions are further computer-executable to implement:

determining one or more image primitives in the image based on the symmetry values.

18. The computer-readable storage medium as recited in claim 12, wherein automatically determining the symmetry value for each of the plurality of pixels in the image comprises:

determining one or more axes of symmetry in the image;

determining one or more axes of symmetry in a down-sampled version of the image;

determining one or more axes of symmetry in an up-sampled version of the image; and

combining the one or more axes of symmetry in the image, the one or more axes of symmetry in the down-sampled version of the image, and the one or more axes of symmetry in the up-sampled version of the image.

19. The computer-readable storage medium as recited in claim 12, wherein automatically determining the symmetry value for each of the plurality of pixels in the image comprises automatically determining the symmetry value for each of the plurality of pixels in the image at a plurality of resolutions.

20. A system, comprising:

at least one processor;

a memory coupled to the at least one processor, wherein the memory is configured to store program instructions executable by the at least one processor to;

determine a symmetry value for each of a plurality of pixels in an image, wherein the symmetry value indicates a strength of one or more symmetries in the image for the respective pixel; and

store the symmetry value for each of the pixels.

21. The system as recited in claim 20, wherein, in automatically determining the symmetry value for each of the plurality of pixels in the image, the program instructions are further executable by the at least one processor to:

determine one or more interest points in the image;

determine a matching symmetric interest point for each interest point, wherein each interest point and matching symmetric interest point comprise a matching interest point pair; and

vote for an axis of symmetry for each matching interest point pair.

22. The system as recited in claim 21, wherein, in automatically determining the symmetry value for each of the plurality of pixels in the image, the program instructions are further executable by the at least one processor to:

determine a symmetric pixel for each axis of symmetry for each of the plurality of pixels;

determine a photometric distortion between an area around each of the plurality of pixels and an area around the corresponding symmetric pixel;

remove the photometric distortion for each of the plurality of pixels;

determine a difference between the area around each of the plurality of pixels and the area around the corresponding symmetric pixel; and

normalize the difference between the area around each of the plurality of pixels and the area around the corresponding symmetric pixel.

23. The system as recited in claim 20, wherein the program instructions are further executable by the at least one processor to:

segment the image based on the symmetry values.

24. The system as recited in claim 20, wherein the program instructions are further executable by the at least one processor to:

annotate the image based on the symmetry values.

25. The system as recited in claim 20, wherein the program instructions are further executable by the at least one processor to:

determine one or more image primitives in the image based on the symmetry values.

26. The system as recited in claim 20, wherein, in automatically determining the symmetry value for each of the plurality of pixels in the image, the program instructions are further executable by the at least one processor to:

determine one or more axes of symmetry in the image;

determine one or more axes of symmetry in a down-sampled version of the image;

determine one or more axes of symmetry in an up-sampled version of the image; and

combine the one or more axes of symmetry in the image, the one or more axes of symmetry in the down-sampled version of the image, and the one or more axes of symmetry in the up-sampled version of the image.

27. The system as recited in claim 20, wherein, in automatically determining the symmetry value for each of the plurality of pixels in the image, the program instructions are further executable by the at least one processor to:

automatically determine the symmetry value for each of the plurality of pixels in the image at a plurality of resolutions.