Intensity fluctuations and natural texturing

Abstract

A model for texturing of surfaces is introduced based on the concept of light intensity fluctuations. During the evaluation of the reflected intensity in the rendering process a non-Gaussian stochastic component is added which is governed by electromagnetic scattering theory. This component simulates the appearence of macroscopic surface irregularities in the image plane by considering not only the mean value of the intensity, given by the usual specular contribution, but also its variance and autocorrelation function. The variance generates the strength and distribution of the intensity fluctuations and the spatiotemporal auto-correlation function can be used to model the form and temporal development of the texture patterns. With an appropriate choice of a few parameters, soft intensity perturbations and bumpy speckle patterns as well as glint effects can be created.