Application of the conjugate gradient method to inverse scattering for penetrable objects

An iterative technique for reconstructing the image of the refractive index of scatterers from scattered far-field data is presented. The inverse scattering problem is treated as an optimization problem in which the refractive index is determined by minimizing the norm of the difference between the measured scattered field and the calculated scattered field for an estimated refractive index. The standard Tikhonov regularization is not used, but an outer contour of the scatterer as a priori information is incorporated at each step of the iteration.<>