Partial image reconstruction adapted to extracting the frequency spectrum of discrete targets in millimeter-wave AIT images

Abstract

Millimeter-wave imaging is used in Advanced Imaging Technology (AIT) screening systems to detect concealed objects based on the received radio frequency (RF) signals. The RF signals are collected and digitized from multiple frequencies and multiple antenna positions. We show that the measured frequency response of a targeted object can determine its complex refractive index and provide information on the material composition. This paper shows a method to compute the frequency spectrum from an image reconstructed using a partial set of antennas for which the radar reflection is most likely to be specular.