1. Fast Separation of Direct and Global Images Using High Frequency Illumination Shree K. Nayar Gurunandan G. Krishnan Columbia University SIGGRAPH Conference Boston, July 2006 Support: ONR, NSF, MERL Michael D. Grossberg City College of New York Ramesh Raskar MERL

2. source surface P Direct and Global Illumination A A : Direct B B : Interrelection C C : Subsurface D participating medium D : Volumetric translucent surface E E : Diffusion camera

3. Related Work (Seitz et. al., ICCV 05) Inverse Light Transport (Sen et. al., Siggraph 05) T Dual Photography

4. Fast Separation of Direct and Global Images Create Novel Images of the Scene Enhance Brightness Based Vision Methods New Insights into Material Properties

5. direct global radiance Direct and Global Components: Interreflections surface i camera source j BRDF and geometry

6. High Frequency Illumination Pattern surface camera source fraction of activated source elements + i

7. High Frequency Illumination Pattern surface fraction of activated source elements camera source + - i

8. Separation from Two Images directglobal

9. Other Global Effects: Subsurface Scattering translucent surface camera source i j

10. Other Global Effects: Volumetric Scattering surface camera source participating medium i j

11. Diffuse Interreflections Specular Interreflections Volumetric Scattering Subsurface Scattering Diffusion

12. Scene

13. DirectGlobal

14. Real World Examples: Can You Guess the Images?

15. Eggs: Diffuse Interreflections DirectGlobal

16. Wooden Blocks: Specular Interreflections DirectGlobal

17. Novel Images

18. Mirror Ball: Failure Case DirectGlobal

19. Photometric Stereo using Direct Images Bowl Shape Source 1 Source 2 Source 3 Direct Global Nayar et al., 1991

20. Kitchen Sink: Volumetric Scattering Volumetric Scattering: Chandrasekar 50, Ishimaru 78 DirectGlobal

21. Novel Image

22. Peppers: Subsurface Scattering DirectGlobal

23. Novel Images

24. Hand DirectGlobal Skin: Hanrahan and Krueger 93, Uchida 96, Haro 01, Jensen et al. 01, Cula and Dana 02, Igarashi et al. 05, Weyrich et al. 05

25. Face: Without and With Makeup GlobalDirect GlobalDirect Without Makeup With Makeup

26. Blonde Hair Hair Scattering: Stamm et al. 77, Bustard and Smith 91, Lu et al. 00 Marschner et al. 03 DirectGlobal

27. Variants of Separation Method Shadow of Line Occluder Shadow of Mesh Occluders Coded Structured Light Shifted Sinusoids

28. Summary Fast and Simple Separation Method Wide Variety of Global Effects No Prior Knowledge of Material Properties Implications: Generation of Novel Images Enhance Computer Vision Methods Insights into Properties of Materials

29. www.cs.columbia.edu/CAVE