Accelerated volume rendering using homogeneous region encoding

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, no work has been done to directly encode homogeneous but not empty regions. 3-D 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 ray-casting and back projection algorithms with a high degree of flexibility.