Tomography of a Minimum Travel Time Ray Tracing on a Triangular Net
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摘要: 针对层析成像模型矩形网格剖分存在的一些问题,提出了复杂结构三角网最小走时射线追踪层析成像方法。以Delaunay三角剖分的优化准则,根据模型点、线、面的几何结构关系,进行三角网格剖分;采用三角网波行面扩展法计算声波初至走时,追踪出任意接收点至激发点处的射线路径,射线路径包含了从接收点至源点的坐标、所在三角单元等信息,形成矩阵方程。应用稳定性较好的联合迭代重构技术求解矩阵方程,得到模型的速度分布。数值模拟结果表明,三角网射线层析成像方法分辨率高,成像结果更接近实际结构形态,有效地解决了矩形网剖分对复杂区域网格参数化灵活性差,速度界面描述精度低等问题。Abstract: In view of problems existed in tomography on rectangular net subdividing to a model,we proposed a triangular net minimum travel time ray tracing tomography method for complex structure.A triangle grid was subdivided based on the Delaunay triangular subdividing criterion and the relationships among the points,lines,and surfaces of the model.The first travel times was calculated with triangular net plane wave propagation method,followed by tracing the ray paths of any receiving point to the excitation point.The ray paths include the informations of the coordinates from receiving points to source points and all triangle cells,and the matrix equation is formed.The matrix equation is conducted by applying SIRT algorithm and the velocity distribution is obtained.The simulation results show that the use of triangular net ray tomography method achieved higher resolution version,and more precisely reflected the actual morphological characteristics.The problems of inflexibility of subdividing elastic wave tomography for complex structure models,and poor definition of velocity interfaces is effectively resolved.
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Keywords:
- triangular net /
- ray tracing /
- plane wave propagation /
- vomputed tomography
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