“All-frequency shadows using non-linear wavelet lighting approximation” by Ng, Ramamoorthi and Hanrahan

We present a method, based on pre-computed light transport, for real-time rendering of objects under all-frequency, time-varying illumination represented as a high-resolution environment map. Current techniques are limited to small area lights, with sharp shadows, or large low-frequency lights, with very soft shadows. Our main contribution is to approximate the environment map in a wavelet basis, keeping only the largest terms (this is known as a non-linear approximation). We obtain further compression by encoding the light transport matrix sparsely but accurately in the same basis. Rendering is performed by multiplying a sparse light vector by a sparse transport matrix, which is very fast. For accurate rendering, using non-linear wavelets is an order of magnitude faster than using linear spherical harmonics, the current best technique.

1. AGRAWALA, M., RAMAMOORTHI, R., HEIRICH, A., AND MOLL, L. 2000. Efficient image-based methods for rendering soft shadows. In Proceedings of SIGGRAPH 2000, 375–384. Google ScholarDigital Library
2. ASHIKHMIN, M., AND SHIRLEY, P. 2002. Steerable illumination textures. ACM Transactions on Graphics 21, 1, 1–19. Google ScholarDigital Library
3. BOLZ, J., FARMER, I., GRINSPUN, E., AND SCHRÖDER, P. 2003. Sparse matrix solvers on the GPU: Conjugate gradients and multigrid. To Appear in ACM Transactions on Graphics. Google Scholar
4. CHEN, W., BOUGUET, J., CHU, M., AND GRZESZCZUK, R. 2002. Light field mapping: Efficient representation and hardware rendering of surface light fields. ACM Transactions on Graphics 21, 3, 447–456. Google ScholarDigital Library
5. COHEN, M. F., AND GREENBERG, D. P. 1985. The hemi-cube: a radiosity solution for complex environments. Computer Graphics (Proceedings of SIGGRAPH 85) 19, 3, 31–40. Google Scholar
6. DEBEVEC, P., AND MALIK, J. 1997. Recovering high dynamic range radiance maps from photographs. Proc. of SIGGRAPH 1997, 369–378. Google ScholarDigital Library
7. DEBEVEC, P., HAWKINS, T., TCHOU, C., DUIKER, H., SAROKIN, W., AND SAGAR, M. 2000. Acquiring the reflectance field of a human face. In Proceedings of SIGGRAPH 2000. Google ScholarDigital Library
8. DEVORE, R. 1998. Nonlinear approximation. Acta Numerica 7, 51–150.Google ScholarCross Ref
9. DORSEY, J., SILLION, F., AND GREENBERG, D. 1991. Design and simulation of opera lighting and projection effects. In Computer Graphics (Proceedings of SIGGRAPH 91), vol. 25, 41–50. Google Scholar
10. DROR, R., LEUNG, T., ADELSON, E., AND WILLSKY, A. 2001. Statistics of real-world illumination. In CVPR 01, II-164-II-171.Google Scholar
11. HECKBERT, P. S., AND HERF, M. 1997. Simulating soft shadows with graphics hardware. Tech. Rep. CMU-CS-97-104, Carnegie Mellon U.Google Scholar
12. LALONDE, P., AND FOURNIER, A. 1999. Interactive rendering of wavelet projected light fields. In Graphics Interface 99, 107–114. Google ScholarDigital Library
13. MALLAT, S. 1998. A Wavelet Tour of Signal Processing (Chapter 9). Academic Press.Google Scholar
14. NIMEROFF, J., SIMONCELLI, E., AND DORSEY, J. 1994. Efficient re-rendering of naturally illuminated environments. In Fifth Eurographics Workshop on Rendering, 359–373.Google Scholar
15. RAMAMOORTHI, R., AND HANRAHAN, P. 2001. An efficient representation for irradiance environment maps. In Proceedings of SIGGRAPH 2001, 497–500. Google ScholarDigital Library
16. SCHRÖDER, P., AND SWELDENS, W. 1995. Spherical wavelets: Efficiently representing functions on the sphere. In Proceedings of SIGGRAPH 1995, 161–172. Google Scholar
17. SLOAN, P., KAUTZ, J., AND SNYDER, J. 2002. Precomputed radiance transfer for real-time rendering in dynamic, low-frequency lighting environments. ACM Transactions on Graphics 21, 3, 527–536. Google ScholarDigital Library
18. SOLER, C., AND SILLION, F. 1998. Fast calculation of soft shadow textures using convolution. In Proceedings of SIGGRAPH 1998, 321–332. Google ScholarDigital Library
19. TEO, P., SIMONCELLI, E., AND HEEGER, D. 1997. Efficient linear rerendering for interactive lighting design. Tech. Rep. STAN-CS-TN-97-60, Stanford University. Google ScholarDigital Library
20. WOOD, D., AZUMA, D., ALDINGER, K., CURLESS, B., DUCHAMP, T., SALESIN, D., AND STUETZLE, W. 2000. Surface light fields for 3D photography. In Proceedings of SIGGRAPH 2000, 287–296. Google ScholarDigital Library