A Modified Phase Shift Migration Algorithm Applied to 2D and 3D Through-the-Wall Imaging

When the PSM (phase-shift migration) is used in TWI (Through-the-wall imaging), the image is defocused due to the presence of the wall. In this paper, a new algorithm based on the PSM method is proposed to tackles this problem. In order to compensate the effects of the wall, the conjugated wall transmissivity is integrated into the imaging formula, which is derived from the spectrum Green´s function for multilayered medium. The two merits of our proposed method are: 1) the wall compensation is manipulated in the spatial frequency domain, which avoids a time-consuming calculation of the incidences angles; 2) the image is reconstructed by the fast Fourier transform (FFT) efficiently. The proposed method is implemented for 2D and 3D applications on synthetic-generated data and applied to the 2D experimental data collected at a test site. The results demonstrate that our method generates high quality focused images and achieves target geometrical identification within a very short time. Therefore, the new method provides a promising real-time solution with high fidelity in TWI.