SAR Imaging of Suicide Bombers Wearing Concealed Explosive Threats

This paper deals with the problem of detecting potential suicide bombers wearing concealed metallic and dielectric objects. The data produced by Millimeter-Wave-Radar system, working on a Multiple Frequency-Multiple Transmitters and Multiple Receivers configuration (MF-MTMR), is synthetically generated by an electromagnetic code based on Finite Differences Frequency Domain (FDFD) method. The numerical code provides the scattered field produced by the subject under test, which is later processed by using a multiple bistatic Synthetic Aperture Radar (SAR) algorithm. The blurring effect produced by the Point Spread Function (PSF) in the SAR image is removed by applying a regularized deconvolution algorithm that uses only magnitude information (no phase). Finally, the SAR algorithm and the deconvolution procedure are tested on a person wearing metallic and dielectric objects. The SAR response of dielectric rods is quite different from the metallic pipes. Our algorithm not only distinguishes between cases but also is capable of estimating the dielectric constant of the rods. Each constitutive parameter directly maps to the dielectric constant of explosive compounds, such as TNT or RDX, making feasible the detection of potential suicide bombers.