In this paper we address an inverse scattering problem whose aim is to determine the geometrical and the physical properties of a variable conducting cylindrical body buried in a half-space. The variable conductivity boundary leads to a mathematically ill-posed nonlinear equation. To overcome this difficulty, the attained system of nonlinear integral equations is reformulated into an optimization problem and solved by using the genetic algorithm. The genetic algorithm is employed to search the global extreme of the object function, such that the shape and the variable conductivity of the scatterer can be reconstructed. Even when the initial guess is far away from the exact one, the genetic algorithm can avoid the local extreme and attain to a global extreme solution sucessfully. In such a case, the gradient-based methods often get stuck in a local extreme. It is found that multiple incident waves from different directions permit good reconstruction of the shape and, to a lesser extent, the conductivity in the presence of noise for the measured data. Numerical results are given to show the effectiveness of the genetic algorithm.
關聯:
International Journal of Applied Electromagnetics and Mechanics 21(2), pp.51-62
