Microwave projection imaging for refractive objects: a new method

The distorted-wave Born and geometrical-optics approximations are used to establish a connection between coherent swept-frequency microwave scattering data and the projections of refractive objects. A reconstruction algorithm based on a generalized back-projection operator is then derived. The algorithm is numerically efficient, robust, and applicable to a wider class of scatterers than are traditional inversion techniques. Results obtained by using both simulated and experimental data sets suggest that the new inversion technique provides improved images over those obtained by using traditional algorithms for the refractive structures tested to date. The method complements the weighted generalized back-projection operator proposed by Beylkin (1984, 1985).