脉冲源反演介质参数的近似波前法

Approximate Wavefront Method for Inverse Medium Parameters by Using the Point Source

在时域内对弹性波动方程退化的非均匀介质声波方程，引入背景场参数与扰动参数，并化为积分方程形式；针对脉冲源情况，根据射线理论中的传递方程和程函方程，对非均匀介质中的波场形式引入一种波前近似形式，得到波散射点满足散射关系曲线及散射波幅值与介质参数扰动比的代数关系方程式；为求解非均匀介质中散射波场及反演介质参数提供了一种方法，通过对一个完整算例全部过程的模拟，验证了此方法的正确性。

The acoustic wave equation derived from the elastic wave equation is studied in the time domain. The referential variables and perturbational variables are introduced.The integral equation of the medium perturbational parameters is obtained. Based on the transmit equation and the eikonal equation of the ray theory in inhomogeneous medium, the approximate form of the wavefront of the wave field in inhomogeneous medium is introduced,and the algebriac equation between the scattering wave amplitude and the perturbation ratios of the medium parameters is obtained. Otherwise, the scattering body figure can be determined by the scatlering curves defined. The method can be used to calculate the wave field in inhomogeneous medium and inverse the medium parameters. The numerical simulation of identifying a scattering body shows the trustworthy of this method.