THz Radar Security Screening Method for Walking Human Torso With Multi-Angle Synthetic Aperture

Abstract

Terahertz (THz) radar imaging has widely adopted for security screening of standoff human body in recent years, owing to its capacities of high resolution, harmless, contactless, and penetrate clothing. However, THz radar security screening for walking human is still a challenge due to the non-rigid motion of walking. To figure it out, a THz radar security screening method for walking human torso is proposed with multi-angle synthetic aperture. In this method, the echo data of walking human torso component is assumed as a rigid motion model within a short time. Particularly, the torso component has the maximum ratio of surface area and echo energy, which means that its motion phase error can be detected after fractional Fourier transform processing. Besides, after the correction and imaging processing, the imaging results under different angles are fused by coherent integration with registration processing to improve the integrity of scattering information, which is incomplete within a short aperture due to self-occlusion and the changes in incident angles. The simulation experiments are conducted to verify the imaging quality and feasibility of the proposed method. Moreover, the real small aperture echo data of moving torso collected by our THz radar (that operates at 330GHz with the bandwidth of 30GHz and the output peak power of 5mW) is processed via the proposed method to indicate the significance of multi-angle imaging.