Estimating magnetic polarizability tensor of buried metallic targets for landmine clearance

This paper addresses the problem of identifying metallic objects in buried landmines and discriminating them from clutter using low frequency electromagnetic induction (EMI) techniques. From dipolar fields, the magnetic polarizability tensor extracted from the target response can be used as a basis for identification. Here, a deterministic nonlinear optimization method is presented to estimate target polarizability matrix and location by fitting a dipole model to EMI data collected above target in a least squares sense. Using finite element simulated data with added synthetic low frequency noise (10 dB SNR), results show initial guess misestimating target position with few centimeters in the transversal (x, y) plane can be corrected very close to the true location. The method is also able to estimate the polarizability tensor to within 12 % error of the true tensor. Keywords-component; Electromagnetic Induction, landmines, UXO, Magnetic polarizability, nonlinear inverse problems.