Advanced Volume Illumination with Unconstrained Light Source Positioning

Advanced illumination models can support depth perception. However, for volume rendering, gradient-based shading models are still the standard. This is because the computation of more advanced lighting effects is expensive and thus strongly affects rendering performance. Nevertheless, interactive frame rates are important for both the interactive design of visual representations and the exploration process. An interactive volumetric lighting model simulates scattering and shadowing to generate high-quality images. Compared to gradient-based shading, this model achieves superior image quality and higher frame rates. To evaluate this model, a user study had participants perform depth perception tasks. The study's results indicate that this model can significantly improve depth perception, compared to conventional gradient-based volume shading. Additionally, because this model isn't based on a gradient computation, it's less sensitive to noise and therefore applicable to imaging modalities suffering from a low signal-to-noise ratio, such as magnetic resonance imaging or 3D ultrasound. © 2006 IEEE.