Millimeter-wave imaging active

Active millimeter-wave imaging for concealed weapon detection... 

Recently, researchers at Agilent have developed a novel active real-time millimeter-wave imaging technique based on a digitally controlled reflecting antenna array [14], This system is described in detail in Section 5.3. 

Other active millimeter-wave imaging systems... 

Fig. 18. Example images from the Agilent active millimeter-wave imaging system. A person is shown carrying simulated explosives (images courtesy of Agilent).

E. N. Grossman and A. J. Miller, Active millimeter-wave imaging for concealed weapons detection, Proceedings of the SPIE - The International Society for Optical Engineering, vol. 5077, pp. 62, 2003. 

Millimeter waves can be used for both active and passive imaging systems. Active imaging systems primarily image the reflectivity of the person/scene including the effect of the object s shape and orientation. Passive systems measure the thermal (black-body) emission from the scene, which will include thermal emission from the environment that is reflected by objects in the scene (including the person). 

A wide variety of imaging system architectures have been designed or proposed for millimeter-wave and terahertz imaging systems. These include passive FPAs, passive mechanically-scanned systems, active mechanically-scanned focused lens systems (both through transmission and reflection), active holographic scanned imaging, and SAR imaging. 

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