Millimeter-wave imaging for concealed weapon detection

Full body, real-time, millimeter-wave imaging systems have been developed at the Pacific Northwest National Laboratory for the detection of body-worn, concealed weapons and contraband at security checkpoints. These security systems employ methods derived from microwave holography techniques that utilize phase and amplitude information recorded over a two-dimensional aperture to reconstruct a focused image of the target. Millimeter-wave imaging is well suited for the detection of concealed weapons or other contraband carried on personnel, since millimeter waves are non-ionizing, readily penetrate common clothing material, and are reflected from the human body and any concealed items. In this paper, wide-bandwidth, three-dimensional, holographic microwave imaging techniques and a full-body, planar, millimeter-wave imaging system are described.