Contour Detection and Hierarchical Image Segmentation

1. Contour Detection and Hierarchical Image Segmentation P. Arbelaez, M. Maire, C. Fowlkes, J. Malik. Contour Detection and Hierarchical image Segmentation. IEEE Trans. on PAMI , 2011. Student: Hsin-Min Cheng Advisor: Sheng-Jyh Wang

2. Outline • Introduction • Contour Detection • Hierarchical Segmentation • Results • Conclusion

3. Introduction • Contour Original Image Contour

4. Introduction • Segmentation Original Image Segmentation

5. Introduction • From Contour to Segmentation Original Image Contour Segmentation

6. Introduction • Goal • Contour Detection • Hierarchical Segmentation from Contours Original Image Contour Segmentation

7. Outline • Introduction • Contour Detection • Hierarchical Segmentation • Results • Conclusion

8. Contour Detection 1. Learn local boundary cues 2. Global framework to capture closure, continuity 3. Local Cues and global cues combination

9. Contour Detection • Learn local boundary cues Local Boundary Cues Image Cue Combination Brightness Model Color Texture

10. Contour Detection • Learn local boundary cues • Brightness • L*a*b* colorspace • Color • L*a*b* colorspace • Texture • Convolve with 17 filters Filters for creating textons

11. Contour Detection • Learn local boundary cues • Oriented gradient of histograms • Example • Gradient magnitude G at location(x, y) • Three scales of r ure 11

12. Contour Detection • Learn local boundary cues • Local Cues Combination ure 12 12

13. Contour Detection • Global framework to capture closure, continuity V: image pixels E: connections between pairs of nearby pixels =>Build a weighted graph G=(V,E) from image

14. Contour Detection • Global framework to capture closure, continuity

15. Contour Detection • Local Cues and global cues combination Local Cues Global cues

16. Outline • Introduction • Contour Detection • Hierarchical Segmentation • Results • Conclusion

17. Hierarchical Segmentation • Multiple Segmentations • Fixed resolution • Hierarchy of Segmentations • Flexible resolution adjustment

18. Hierarchical Segmentation • From contours to segmentation • Hierarchical segmentation by iterative merging

19. Hierarchical Segmentation • From contours to segmentation • Watershed Transform • Concept

20. Hierarchical Segmentation • From contours to segmentation • Watershed Transform • Example

21. Hierarchical Segmentation • From contours to segmentation • Watershed Transform Artifacts Boundary strength Weight each arc

22. Hierarchical Segmentation • From contours to segmentation • Oriented Watershed Transform WT OWT

23. Hierarchical Segmentation • Hierarchical segmentation by iterative merging • Hierarchical segmentation • Example

24. Brief Summary Original Image - Local cues - Global cues Oriented Gradient of histograms Contour Oriented Watershed Transform Hierarchical Segmentation Iterative Merging

25. Outline • Introduction • Contour Detection • Hierarchical Segmentation • Results • Conclusion

26. Result

27. Result

28. Result • BSDS300 Dataset Evaluation of contour detector Evaluation of segmentation algorithms

29. Outline • Introduction • Contour Detection • Hierarchical Segmentation • Results • Conclusion

30. Conclusion • A high performance contour detector, combining local and global image information • A method to transform any contour detector signal into a hierarchy of regions while preserving contour quality

31. Reference • P. Arbelaez, M. Maire, C. Fowlkes and J. Malik. Contour Detection and Hierarchical Image Segmentation. IEEE TPAMI, Vol. 33, No. 5, pp. 898-916, May 2011 • P. Arbelaez, M. Maire, C. Fowlkes and J. Malik. From Contours to Regions: An Empirical Evaluation. In CVPR 2009. • P. Arbelaez and L. Cohen. Constrained Image Segmentation from Hierarchical Boundaries. In CVPR 2008.