Fast global illumination for interactive volume visualization

Abstract

High quality global illumination can enhance the visual perception of depth cue and local thickness of volumetric data but it is seldom used in scientific visualization because of its high computational cost. This paper presents a novel grid-based illumination technique which is specially designed and optimized for volume visualization purpose. It supports common light sources and dynamic transfer function editing. Our method models light propagation, including both absorption and scattering, in a volume using a convection-diffusion equation that can be solved numerically. The main advantage of such technique is that the light modeling and simulation can be separated, where we can use a unified partial-differential equation to model various illumination effects, and adopt highly-parallelized grid-based numerical schemes to solve it. Results show that our method can achieve high quality volume illumination with dynamic color and opacity mapping and various light sources in real-time. The added illumination effects can greatly enhance the visual perception of spatial structures of volume data.