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A systematic approach to robust preconditioning for gradient-based inverse scattering algorithms

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Author

Summary, in English

This paper presents a systematic approach to robust preconditioning for gradient-based nonlinear inverse scattering algorithms. In particular, one- and two-dimensional inverse problems are considered where the permittivity and conductivity profiles are unknown and the input data consist of the scattered field over a certain bandwidth. A time-domain least-squares formulation is employed and the inversion algorithm is based on a conjugate gradient or quasi-Newton algorithm together with an FDTD-electromagnetic solver. A Fisher information analysis is used to estimate the Hessian of the error functional. A robust preconditioner is then obtained by incorporating a parameter scaling such that the scaled Fisher information has a unit diagonal. By improving the conditioning of the Hessian, the convergence rate of the conjugate gradient or quasi-Newton methods are improved. The preconditioner is robust in the sense that the scaling, i.e. the diagonal Fisher information, is virtually invariant to the numerical resolution and the discretization model that is employed. Numerical examples of image reconstruction are included to illustrate the efficiency of the proposed technique.

Publishing year

2008

Language

English

Publication/Series

Inverse Problems

Volume

24

Issue

2

Document type

Journal article

Publisher

IOP Publishing

Topic

  • Electrical Engineering, Electronic Engineering, Information Engineering

Status

Published

Research group

  • Electromagnetic theory

ISBN/ISSN/Other

  • ISSN: 0266-5611