  In this paper, we report a polarimetry-based THz imaging technique that
highly benefits from backscatter data reflected from PEC hidden objects,
considering the edge diffractions of the object as a key point. First, based on
physical optic principles, we investigate the cross-polarized reflections of
PEC objects in order to show the superiority of reflections of the edges to
other parts of the object. Next, we represent the results of a near filed
simulation using Feko to study the differences between cross and co-polarized
reflections of a PEC object and the human body beneath it. To a further
illustration, our experimental results are presented in which we utilized a THz
imaging system consisting of a semiconductor-based THz camera and a horn
antenna operating at 100 GHz as the source. Cross-polarized backscatter data is
analyzed to distinguish PEC objects from the human body. Besides, we used two
orthogonal linear polarizations of the source to maximize backscattering from
orthogonal edges. Experimental results show a noticeable improvement in edge
detection of hidden objects indicating that this method can result in high
accuracy in THz real-time imaging.
