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An efficient representation for irradiance environment maps
2001
Proceedings of the 28th annual conference on Computer graphics and interactive techniques - SIGGRAPH '01
We consider the rendering of diffuse objects under distant illumination, as specified by an environment map. Using an analytic expression for the irradiance in terms of spherical harmonic coefficients of the lighting, we show that one needs to compute and use only 9 coefficients, corresponding to the lowest-frequency modes of the illumination, in order to achieve average errors of only 1%. In other words, the irradiance is insensitive to high frequencies in the lighting, and is well
doi:10.1145/383259.383317
dblp:conf/siggraph/RamamoorthiH01a
fatcat:oo74jwkcpraqnmdjc47zeiabcq