Ray Casting Algorithm Using Segment Composition
基于片段的光线投射算法

The traditional ray casting algorithm which is the most accurate volume rendering algorithm suffers from high computational complexity. In order to improve the traditional algorithm, a new ray casting accelerating algorithm, which is called SRC(segment-based ray casting) for short, is proposed in this paper. There are many optimization techniques making use of data coherence to reduce process time in former researches. SRC works the same way, while the optimization is emphasized in the composition stage instead of traditional data preprocessing stage. SRC combines sequential samples which have the similar optical values into a segment. The segments substitute for the samples to be the basic composition units. Therefore, the number of composition operations is reduced. The efficiency of SRC is demonstrated by both theoretical reasoning and experiments results. The experiments results show that software SRC can improve the rendering performance by about 30% compared with traditional ray casting without degrading image quality noticeably and hardware SRC can improve the performance by nearly the same multiple as the length of the segment. In addition, SRC is easy to combine with other successful optimizations.