Fast Volume Rendering Algorithm of Octree Encoded Volume

This paper proposes a novel template-based raycasting scheme using Shear-Warp factorization for expediting parallel viewing of volumetric datasets. The volume coding scheme based on an efficient octree data structure is presented and the octree blocks are adaptively chosen to minimize unnecessary access process. The algorithm exploits the uniform shape, orientation and size of the “nonempty” octree blocks by building templates for ray/block intersections in the case of RayCasting. The volume stored in octrees requires basic tree traversal operations such as point location, region location, and neighbor searches. This paper presents simple and efficient methods for performing searching and locating operations that are inherently non-recursive and reduces the number of comparisons with poor predictive behavior. The methods are table-free, thereby reducing memory accesses and avoiding the costly intersection computation. The high quality human body interior images of a large dataset can be generated by the proposed approach on a conventional PC platform.