Abstract

We present a new volume rendering algorithm using raycasting and texture mapping formulations for parallel projection in this paper. The volume is represented and stored in an efficient octree data structure. The octree blocks are adaptively chosen to minimize unnecessary processing of empty voxels. The algorithm exploits the uniform shape, orientation and size of the octree blocks by building templates for ray/block intersections in the case of raycasting and Z-plane/block intersections in the case of texture mapping. Such templates are then pasted to all the octree blocks thereby avoiding the costly intersection computation. While Octree is an established technique to accelerate volume visualization, it has never been used in conjunction with templates and texture mapping. Together as an integrated acceleration tool, it is much more efficient than using octree alone. We have found that the use of template speeds up the rendering by a factor of three for raycasting and by a factor of six for texture mapping. The algorithm is also efficient in terms of memory requirements, can generate high quality images, and is very suitable for parallelization.

Citations