1. Novel Depth Cues from Uncalibrated Near-field Lighting Sanjeev J. Koppal and Srinivasa Narasimhan Carnegie Mellon University Sponsors: ONR and NSF

2. Distant Lighting Sun Scene Parallel Rays

3. Near-field Lighting Indoor Night Underground Underwater

4. Scene Calibrated Near Point Light Source Inverse-square fall-off can give depth information (Clark 92, Iwahori et al 94, Kao and Fuh 95, Magda et al 01, Zickler et al 02, Prados and Faugeras 05) 1 R 2

5. Our Key Idea Scene Move an uncalibrated point light source in a line or a plane ‘baseline’

6. Appearance Model BRDF Illumination and Viewing angles Foreshortening Distance to Source

7. Experimental Setup LED Scene Camera

8. Plane-Scene Intersections for Lambertian Scenes

9. Light source moves in a line t = i Scene Camera t = 0 t = n

10. Maxima in Intensity Scene Camera Plane perpendicular to light source path. t = i t = 0 t = n

11. Lambertian Scenes Lambertian Model: Solve for maxima location: Expression for maxima: Albedo Quadratic Shortest distance to light source path If D is small, maxima happens at t = i

12. Moving the Light Source in a Line

14. Input Images

15. Plane-Scene Intersections

16. Similar to Structured Light

17. Rough Earthen Pot

18. Painted House

19. Metal Office Desk

20. Wax Candle

21. Depth Ordering for Homogeneous Scenes

22. Light source moves in a plane Scene Camera

23. Integrating the Profile Integral of Profile: P Q Overlapped Incident Angles P Q S < S if: Works for convex Lambertian scenes p q

24. Moving the Light Source in a Plane

26. Input Images

27. Depth Ordering

28. Plotting ordering as a pseudo-depth

29. Plastic Beach Ball

31. Polyresin Statue

33. Depth Orderings from Different ‘Views’

34. Depth Orderings from Left Plane

35. Depth Orderings from Image Plane

36. Depth Orderings from Right Plane

37. Symmetry Pairs for Homogeneous Scenes

38. Matching Profiles Scene Camera

39. Matching Profiles

40. Light source moves in reflection plane

42. Input Images

43. Symmetry Pairs

44. Metal Office Desk

45. Conclusions Line or plane paths for a near light source are a ‘baseline’. Depth cues can be obtained from such uncalibrated light paths. The cues are from the light source ‘viewpoint’ and not from the camera.