关键词: 速度模型, Level set, 多重拷贝, 速度间断面, 二叉树

Abstract: This paper presents a novel representation method for describing velocity models. Velocity discontinuity is embedded into model in the form of zero-value contour of an implicit function. Strategy of multiple copies is to properly handle the contradictory interpolation of velocity value at the boundary of discontinuities. The representation method can be applied to describe very complicated velocity models such as the faulted interface with non-manifold nature and multiple value surfaces. In applications based on the ray theory, signed distance function and velocity discontinuity binary tree enable fast access to velocity information of arbitrary point and easy detection of ray-interface intersection. The model can make the ray propagate positively and honor Snell's law strictly when facing velocity interface and thus improve the accuracy of ray path. Two groups of ray tracing examples verify the effectiveness of the method.

Key words: velocity model, level set, multiple copies, velocity discontinuity, binary tree