A Fast Diffraction Tomography Algorithm for 3-D Through-the-Wall Radar Imaging Using Nonuniform Fast Fourier Transform

This letter proposes the application of the nonuniform fast Fourier transform to the diffraction tomography (DT) image reconstruction method for 3-D through-the-wall radar imaging which leads to a significant speed-up of the image reconstruction procedure. This speed-up is of critical importance in real-time imaging systems since during a long time of imaging, the target displacement may cause errors in detection. Through simulation and experimental examples, the method is validated. In addition, the improved speed of the proposed algorithm is demonstrated by comparing its CPU-time with that of the conventional DT method.

I. Introduction

Through-the-wall radar imaging (TWRI) has broad civilian and military applications for detecting and imaging targets behind walls, such as rescue operations, urban warfare, and surveillance. By sending signals to the targets, which are hidden behind a wall and receiving the scattered signals, an image of the targets can be reconstructed using numerous methods; among which, the diffraction tomography (DT) method is one of the most widely used due to its simplicity, low-computation requirements, and high processing speed [1]. Considering a real-time imaging scenario wherein the targets may move, the reduction in processing time is of great importance.