Electromagnetic Imaging for an Imperfectly Conducting Cylinder Buried in a Three-Layer Structure by the Genetic Algorithm

The imaging of an imperfectly conducting cylinder buried in a three-layer structure by the genetic algorithm is investigated.An imperfectly conducting cylinder of unknown shape and conductivity buried in the second layer scatters the incident wave from the first layer or the third layer.We measure the scattered field in the first and third layers.Based on the boundary condition and the recorded scattered field, a set of nonlinear integral equations is derived and the imaging problem is reformulated into an optimization problem.The genetic algorithm is then employed to find out the global extreme solution of the cost function.Numerical results demonstrated that, even when the initial guess is far away from the exact one, good reconstruction can be obtained.In such a case, the gradient-based methods often get trapped in a local extreme.In addition, the effect of uniform noise on the reconstruction is investigated.