Practical Construction of Reflectances for Spectral Rendering

Yinlong Sun
Purdue University
Department of Computer Sciences
W Lafayette, IN 47907-1398


We propose a method to construct practical reflectances for spectral rendering. A set of 1400 real reflectances are measured and more spectra with higher saturated colors are generated using Bouguer’s law. These spectra serve as the basis for constructing the spectra for any colors. Given a color triplet P, in the color space, we find a small local tetrahedron such that it contains P and the reflectances at the vertices are known. Thus the spectrum at P is constructed using trilinear interpolation. Our derived spectra correspond closely to real spectra and the transformation works for a large volume of color space. This method of spectral construction has been applied to texture mapping and simulating wavelength-dependent phenomena in spectral rendering.