CROSS-BOREHOLE INVERSE SCATTERING USING A BOUNDARY FINITE-ELEMENT METHOD

The problem of the reconstruction of the shape of a perfectly conducti ng cylinder in a cross-borehole configuration is addressed. The initia l data is the harmonic electromagnetic field diffracted by the object to a receiving borehole. The method is based on an iterative conjugate gradient algorithm which requires the solving of two reciprocal direc t diffraction problems at each step. These problems are investigated w ith a rigorous boundary integral method and finite elements. A simple and original regularization scheme is presented, which ensures the rob ustness of the algorithm. Numerical examples with lossy embedding medi a and additional random noise for both E parallel to and H parallel to polarizations are given.