Volume processing-assisted volume rendering

Previous accelerated volume rendering techniques have used auxiliary hierarchical datastructures to skip empty and homogeneous regions. Although some recent research has taken advantage of more efficient direct encoding techniques to skip empty regions in volume data, no work has been done to directly encode homogeneous regions for the purpose of accelerated volume rendering. Three-dimensional distance transforms previously used to encode empty space can be extended to preprocess homogeneous regions as well, and these regions can be efficiently encoded and incorporated into volume rendering with a high degree of flexibility. In this paper, we show that empty and homogeneous regions can be directly encoded and used to accelerate volume ray-casting and forward-projection rendering algorithms.