A modified linear travel-time interpolation ray tracing algorithm

作者:Guo Yali*; Han Yan; Wang Liming; Liu Linmao
来源:Russian Journal of Nondestructive Testing, 2014, 50(7): 426-434.
DOI:10.1134/S1061830914070043

摘要

Ray tracing is the key technology of computerized tomography, the accuracy of ray tracing decides the tomography accuracy. The linear travel-time interpolation ray tracing algorithm is more rapid and accurate than the other conventional methods in calculating travel-time and paths of tracing rays, but it has the drawbacks: the formula of interpolation nodes position has limitations and ray directions are considered incompletely when calculating the minimum travel-time and ray paths. This paper perfects the formula of interpolation nodes position based on the original algorithm. Omni-directional scanning method is put forward to calculate the minimum travel-time of all grid nodes in forward processing; in the transition points of velocity change, in order to improve the ray tracing accuracy, interpolation nodes should be increased and omni-directional scanning method is used to search for ray paths in backward processing. The numerical simulation experiments show that the improved algorithm is more accurate in calculating minimum travel-time and ray paths and can better adapt to the complex medium compared with original LTI.