1. Measuring the Ecological Statistics of Figure-Ground Charless Fowlkes, David Martin, Jitendra Malik

2. Is there an Ecological Justification for Figure-Ground Cues? Size Surroundedness Convexity Lower-Region Symmetry … Are figural regions in the natural world really more convex?

3. Figure-Ground Labeling 200 images each labeled by 2 subjects

4. Consistency – 88% agreement Agreement doesn’t differ with edge length

5. Local Figural Assignment Cues Size and Surroundedness [Rubin 1915] Convexity [Metzger,Kanizsa] Lower-Region [Vecera, Vogel & Woodman 2002]

6. Size(p) = log(A F / A G ) Size : G F p

7. Convexity(p) = log(C F / C G ) Convexity:

9. Aboveness(p) = cos(  ) Aboveness:  center of mass

10. Empirical Frequencies of Size, Convexity and Aboveness. 1200 sample points per image

12. Learning Segmentation From Common-Fate, or not? Charless Fowlkes, Dave Martin

13. Benchmark Image Estimated Affinity (W) Edge Cues Region Cues Learning Similarity Cues Human Segmentations Groundtruth Affinity (S) Segment

15. Learning Segmentation From Common Fate? Infants group by common fate before they learn other static similarity cues. DVDs provide huge quantity of easily accessible data but no ground-truth segmentations.

16. Learning Segmentation From Common Fate? Track points using Lucas-Kanade Cluster into 2 motion groups Transfer groups to image pixels and use as ground truth for pairwise affinity cues.

19. Local Boundary Detection in Natural Images: Matching Human and Machine Performance Dave Martin, Charless Fowlkes, Laura Walker, Jitendra Malik

20. Boundary Detection Image Boundary Cues Model PbPb Challenges: texture cue, cue combination Goal: learn the posterior probability of a boundary P b (x,y,  ) from local information only Cue Combination Brightness Color Texture

21. Non-BoundariesBoundaries T BC

22. Two Decades of Boundary Detection

23. Local Boundary Detection Solved? Clearly top-down, high level knowledge is utilized by humans

24. Test Humans on Local Patches

26. Did you see a boundary running through the center of the patch? [Y/N]

27. radius: 9, 18, 36 humans: 78, 83, 85 F-Measure at r = 9 Humans: 78 Machines: 78