Modeling the interaction of light between diffuse surfaces

TLDR

Current light reflection models in computer graphics ignore object‑to‑object reflection between diffuse surfaces, leading to inaccurate global illumination. The study introduces a method to model light interaction between diffusely reflecting surfaces. The method, adapted from thermal‑engineering techniques, models finite‑area diffuse sources, color‑bleeding, and direct illumination for ideal diffuse reflectors, and is demonstrated with a simple environment and physical‑model photographs. The resulting surface intensities are observer‑position independent, enabling preprocessing for dynamic sequences.

Abstract

A method is described which models the interaction of light between diffusely reflecting surfaces. Current light reflection models used in computer graphics do not account for the object-to-object reflection between diffuse surfaces, and thus incorrectly compute the global illumination effects. The new procedure, based on methods used in thermal engineering, includes the effects of diffuse light sources of finite area, as well as the “color-bleeding” effects which are caused by the diffuse reflections. A simple environment is used to illustrate these simulated effects and is presented with photographs of a physical model. The procedure is applicable to environments composed of ideal diffuse reflectors and can account for direct illumination from a variety of light sources. The resultant surface intensities are independent of observer position, and thus environments can be preprocessed for dynamic sequences.