Polarimetric bistatic GPR imaging and detection of landmines in the near field with the “Vampire Effect”

摘要

GPR images invariably suffer from a bandwidth restriction due to the low pass characteristics of the air-ground interface and are usually not clear enough to differentiate between what is a landmine and what is harmless clutter. The presence of clutter in the subsurface therefore contributes to high false alarm rates when landmine detection schemes are attempted. A landmine detection algorithm based on the vampire signature has been proposed and has been tested to verify its validity. The method involves the construction of a spatial filter from polarimetric data in order to enhance objects that exhibit the vampire effect while suppressing objects that do not. So far, the method has several significant limitations, most notably that the position and orientation of the symmetric scatters is strictly confined to be directly below the SAR path and that the target symmetry planes must include both antennas as well as the scan path. In this paper, the effects of off-centered measurements whereby the antennas are not necessarily contained in the target symmetry plane are discussed.