A point source method for inverse acoustic and electromagnetic obstacle scattering problems

We present the mathematical foundation for a point source method to solve some inverse acoustic and electromagnetic obstacle scattering problems in three dimensions. We investigate the inverse acoustic scattering problem by a sound-soft and a sound-hard scatterer and the inverse electromagnetic scattering problem by a perfect conductor. Two independent approaches to the method are presented which reflect its strong relation to basic properties of obstacle scattering problems.