一种新的基于多模板快速推进算法和最速下降法的射线追踪方法

A new ray tracing approach based on both multistencils fast marching and the steepest descent

本文提出了一种新的射线追踪方法,该方法将射线追踪分为两个过程:首先使用多模板快速推进算法(MSFM)从源点开始计算已知速度场各网格节点的波前传播时间;然后使用最速下降方法从接收点开始向源点沿旅行时梯度最快下降方向追踪射线路径。与传统的快速推进方法(FMM)及其改进算法相比,多模板快速推进算法(MSFM)使用两个模板计算邻点旅行时,同时考虑了水平、垂直及对角线方向上的信息,能大大提高旅行时的计算精度和计算效率。为了验证新射线追踪方法的计算精度和计算效率,本文对两个速度模型进行了数值模拟,并将模拟结果与基于FMM和高精度快速推进方法(HAFMM)的最速下降射线追踪方法计算结果进行对比。对比结果表明,本文方法是一种有效的射线追踪方法,并且在计算精度和计算效率上都优于基于FMM和HAFMM的射线追踪方法。

We propose a new ray tracing approach in two steps.First wavefront propagation times of all grid points in a known velocity field are calculated using the multi-stencils fast marching method(MSFM).Then the ray path with the minimum traveltime can be easily obtained by following the steepest gradient direction from the receiver to the transmitter.Contrast to conventional fast marching method(FMM)and its improved algorithms,MSFM algorithm calculates traveltime using two stencils at the same time,and the information in diagonal direction can be included,thus the calculation accuracy and efficiency can be greatly improved.In order to verify the accuracy and efficiency of the new ray tracing method,we test the proposed scheme on two synthetic velocity models.We compared our result with those obtained by FMM and the high accuracy fast marching method(HAFMM).This comparison indicates that the proposed ray tracing technique is efficiency and achieves better results both on accuracy and efficiency compared to the FMM based and the HAFMM based steepest descent ray tracing methods.