Three-Dimensional Real-Time Through-the-Wall Radar Imaging With Diffraction Tomographic Algorithm

In this paper, a 3-D diffraction tomographic algorithm is proposed for real-time through-the-wall radar imaging (TWRI). The spectral expansion of the three-layered medium dyadic Green's function is employed to derive a linear relationship between the spatial Fourier transforms of the image and the scattered field under Born approximation. Then, the image can be efficiently reconstructed with inverse fast Fourier transform (IFFT). The linearization of the inversion scheme and the easy implementation of the algorithm with FFT/IFFT make the diffraction tomographic TWRI algorithm suitable for on-site applications. The 3-D polarimetric TWRI is investigated using the proposed algorithm for the enhanced target detection and feature extraction as well as mitigation of the wall effect in the cross-polarization. Numerical and experimental results are presented to show the effectiveness and high efficiency of the proposed algorithm for 3-D real-time TWRI.