Inverse scattering of a buried imperfect conductor by the genetic algorithm

Inverse scattering of an Imperfectly conducting cylinder buried in a half-s pace is presented. A conducting cylinder of unknown shape and conductivity Is buried in one half-space and scatters the incident field from another ha lf-space. Based on the measured scattered field and the boundary condition, a set of nonlinear Integral equations is derived and the inverse problem i s reformulated into an optimization problem. The genetic algorithm is then employed to find the global extreme solution of the object function. As a r esult, the shape and the conductivity of the scatterer can be reconstructed . Even when the initial guess is far away from the exact one, the genetic a lgorithm can avoid the local extreme and converge to a global extreme solut ion. In such a case, the gradient-based method often gets stuck In a local extreme. Numerical results are given to show the effectiveness of the genet ic algorithm. Multiple, incident directions permit good reconstruction of s hape and, to a lesser extent, conductivity in the presence of noise in meas ured data. (C) 2001 John Wiley & Sons, Inc.