Spectral Rendering of Global Illumination Models with Presence of Participating Media

Abstract

Many algorithms for synthesizing scenes with participating media assumed that absorption coefficients and scattering coefficients are all the same for every wavelength or every primaries of the RGB color mode. In another word, the scattering coefficients and absorption coefficients are treated as wavelength independent. Hence, the color of participating media rendered is always white. Furthermore, since transmittances of participating media are nonlinear, it’s hard to map the fraction of transmittances from spectra domain to RGB color domain. Thus a spectral rendering method is needs for synthesizing images with presence of participating media. In this paper, we present a spectral rendering method for synthesizing images containing participating media. The scattering coefficients and absorption coefficients are treated as wavelength dependent to meet the requirements of realistic world. Instead of using OPAW (One Path One Wavelength) and stochastic processes to render participating media even though they are colored.