Methods and apparatus for detecting objects. In one embodiment, a person entering a secured or “Safe Zone™” is illuminated with low-power polarized radio waves. Differently polarized waves which are reflected back from the person are collected and measured. In a preferred embodiment, concealed...http://www.google.de/patents/US6856271?utm_source=gb-gplus-sharePatent US6856271 - Signal processing for object detection system
