PNNL

Abstract

PNNL has continued to advance the cylindrical imaging technology using higher frequency ranges of 40 - 60 GHz and 90 - 100 GHz, and polarimetric imaging techniques. Higher frequency allows for greater resolution and the detection of smaller or more subtle threat objects. Polarimetric techniques can improve detection and enhance privacy by accenting raised objects, edges, and corners, while reducing or eliminating the reflection from smooth surfaces of the body. PNNL has also developed a standoff, three-dimensional imaging technique and prototype that operates near 350 GHz. This technique allows screening at ranges of 2 - 10 meters, and may be extended to operate at up to 20 meters. The prototype system uses focusing optics coupled to a high-speed mirror scanning system and can obtain an image in 10 seconds, which is sufficiently fast to conduct extensive imaging tests on cooperative subjects. A future prototype is expected to operate at multiple frames per second to allow imaging in less controlled environments. In this paper, these advanced imaging techniques are described in detail, and numerous experimental imaging results are shown.