层状介质中三维物体重构的对比源反演算法

对比源反演（CSI）算法将反演问题转化为求解成本泛函的极小值问题,从而形成重构对比源和对比度的迭代序列。开发了一种三维CSI算法对层状介质中的三维物体进行重构,该算法是对二维对比源反演算法的推广。该算法无须正演计算,亦无须人为地选择正则化参数,反演过程更稳定。CSI的每一次迭代过程均采用快速Fourier变换技术计算并矢Green函数算子及其共轭算子,确保了该算法在三维层状介质情况下的高效率。复杂模型的反演结果说明,CSI算法对重构层状介质中的任意三维异常体是非常有效的。

Contrast source inversion algorithm for reconstructing 3-D objects in stratified medium

Contrast source inversion(CSI) algorithm recasts the inversion problem as a minimization of a cost functional,thus an iterative sequence is formed to reconstruct the contrast sources and contrasts.A 3-D CSI algorithm was developed to reconstruct 3-D objects in stratified medium.It is an extension of 2-D CSI algorithm.As there is no need for the forward solver and a manual selection of regularization parameter in the algorithm,the inversion process is more stable.The fast Fourier transform technology is adopted to calculate the dyadic Green's operator and its adjoint operator during each iteration of CSI,which ensures the high efficiency of the algorithm in stratified medium.The inversion results for some complicated models obtained from the CSI algorithm show that the algorithm is very efficient in reconstructing arbitrary 3-D inhomogeneous objects in a stratified medium.