Multi-Frequency Backscattering Tomography (MFBT) for Boundary Scattering and for Volume Scattering

The Multi-Frequency Backscattering Tomography (MFBT) for boundary scattering based on the Physical Optics approximation is formulated in this paper. It is shown that the reconstruction formulas are the same as the MFBT for volume scattering (Wu and Araujo, 1991) except for a factor of ik/2. The reconstruction algorithm using direct FT makes the method extremely fast compared with other multifrequency migration or inversion methods, even much faster than the single-frequency diffraction tomography. Numerical tests show that for large scatterers or interfaces the MFBT for boundary scatterirlg give better results than that for volume scattering.