1Signal Processing using Spherical Harmonics ECE 551- Final Paper

Abstract—This paper explores the use of Spherical Harmonics to represent the reflectance function of a 3D surface with known geometry. It is shown that reflectance can be conceived of as a convolution in the angular domain. Spherical Harmonics are used to define a frequency domain in which convolution in the angular domain is equivalent to multiplication in the spherical harmonic frequency domain. This representation leads to novel insights into the reflectance function as well as establishes the conditions for inverse rendering