Boundary cell-based acceleration for volume ray casting

ÐSeveral e€ective acceleration techniques for volume rendering o€er ecient means to skip over empty space, providing signi®cant speedup without a€ecting image quality. The e€ectiveness of such an approach depends on its ability to accurately estimate the object boundary inside a volume with minimal computational overhead. We propose a novel boundary cell-based acceleration technique for ray casting which skips over empty space by accurately calculating the intersection distance for each ray. Very short distance estimation time is achieved by exploiting a projection template to calculate the parallel-projection values of each boundary cell and the coherency of adjacent cells. Since no hardware acceleration is used, the projection procedure can also be eciently parallelized. Experimental results are provided to demonstrate the performance of our new algorithm. # 1999 Published by Elsevier Science Ltd. All rights reserved