Inverse Imaging Using Total Field Measurements

Most microwave inverse imaging algorithms rely on measurements of both the total and the incident electric field in order to estimate the dielectric properties of an unknown scattering object (SO). We propose a new technique to jointly estimate the incident field and relative permittivity of a heterogeneous dielectric object from measurements of the total electric field alone. For the first task, we express the incident field as a collection of plane waves and estimate the wave coefficients from the given data by leveraging the sparsity of the plane wave spectrum and obtain the solution via a constrained reweighted L-1 norm minimization technique. Subsequently, we estimate the permittivity and geometry of the SO using a twofold subspace optimization method. We evaluate the performance of our algorithm on synthetically generated object and experimental data. For synthetic objects, the accuracy in reconstruction of the incident field and the relative permittivity is approximate to 93% for field measurements with a 15-dB signal-to-noise ratio, while the accuracy obtained for an experimental data set was approximate to 90%.