Abstract
In this paper, we present a new SH operation, called spherical harmonics scaling, to shrink or expand a spherical function in the frequency domain. We show that this problem can be elegantly formulated as a linear transformation of SH projections, which is efficient to compute and easy to implement on a GPU. Spherical harmonics scaling is particularly useful for extrapolating visibility and radiance functions at a sample point to points closer to or farther from an occluder or light source. With SH scaling, we present applications to low-frequency shadowing for general deformable object, and to efficient approximation of spherical irradiance functions within a mid-range illumination environment.
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Annen, T., Kautz, J., Durand, F., Seidel, H.P.: Spherical harmonic gradients for mid-range illumination. In: European Symposium on Rendering, pp. 331–336 (2004)
Ng, R., Ramamoorthi, R., Hanrahan, P.: Triple product wavelet integrals for all-frequency relighting. In: SIGGRAPH ’04, pp. 477–487 (2004)
Ramamoorthi, R., Hanrahan, P.: An efficient representation for irradiance environment maps. In: SIGGRAPH ’01, pp. 497–500 (2001)
Ren, Z., Wang, R., Snyder, J., Zhou, K., Liu, X., Sun, B., Sloan, P.P., Bao, H., Peng, Q., Guo, B.: Real-time soft shadows in dynamic scenes using spherical harmonic exponentiation. In: SIGGRAPH ’06 (2006)
Sloan, P., Kautz, J., Snyder, J.: Precomputed radiance transfer for real-time rendering in dynamic, low-frequency lighting environments. In: SIGGRAPH ’02, pp. 527–536 (2002)
Sloan, P.P., Luna, B., Snyder, J.: Local, deformable precomputed radiance transfer. ACM Trans. Graph. 24(3), 1216–1224 (2005)
Westin, S.H., Arvo, J., Torrance, K.E.: Predicting reflectance functions from complex surfaces. In: SIGGRAPH 1992, pp. 255–264 (1992)
Zhou, K., Hu, Y., Lin, S., Guo, B., Shum, H.Y.: Precomputed shadow fields for dynamic scenes. ACM Trans. Graph. 24(3), 1148–1155 (2005)
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Wang, J., Xu, K., Zhou, K. et al. Spherical harmonics scaling . Visual Comput 22, 713–720 (2006). https://doi.org/10.1007/s00371-006-0057-8
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DOI: https://doi.org/10.1007/s00371-006-0057-8