2-DIMENSIONAL LOCATION AND SHAPE RECONSTRUCTION

A method for reconstructing the location and the shape of a bounded im penetrable object from measured scattered field data is presented. The algorithm is, in principle, the same as that used for reconstructing the conductivity of a penetrable object and uses the fact that for hig h conductivity the skin depth of the scatterer is small, in which case the only meaningful information produced by the algorithm is the boun dary of the scatterer. A striking increase in efficiency is achieved b y incorporating into the algorithm the fact that for large conductivit y the contrast is dominated by a large positive imaginary part. This f act, together with the knowledge that the scatterer is constrained in some test domain, constitute the only a priori information about the s catterer that is used. There are no other implicit assumptions about t he location, connectivity, convexity, or boundary conditions. Some ref inements of the algorithm which reduce the number of points at which t he unknown function is updated are incorporated to further increase ef ficiency. Results of a number of numerical examples are presented whic h demonstrate the effectiveness of the location and shape reconstructi on algorithm.