Proceedings Article | 5 May 2009
Proc. SPIE. 7309, Passive Millimeter-Wave Imaging Technology XII
KEYWORDS: Extremely high frequency, Polarization, Reflection, Imaging systems, Image processing, Reflectivity, 3D modeling, Upconversion, Passive millimeter wave imaging, Dielectric polarization
Passive millimeter-wave (mmW) imaging has many specific defense, security and safety applications, due to the fact
that all terrestrial bodies above absolute zero are emissive, and these wavelengths are not scattered by normal obscurants
such as haze, fog, smoke, dust, sandstorms, clouds, or fabrics. We have previously demonstrated results from the
construction of a 94 GHz passive mmW far-field imaging system utilizing optical upconversion, which imaged in only
horizontal polarization. The effective radiometric temperature of an object is a combination of the object's surface and
scattered radiometric temperatures. The surface radiometric temperature is a function of the object's emissivity, which
is polarization dependent. Imaging with radiometric temperature data from both polarizations will allow a greater
identification of the scene being imaged, and allow the recognition of subtle features which were not previously
observable. This additional functionality is accomplished through the installation of added equipment and programming
on our system, thus allowing the simultaneous data collection of imagery in both polarizations. Herein, we present our
experimental procedures, results and passive mmW images obtained by using our far-field imaging system, a brief
discussion of the phenomenology observed through the application of these techniques, as well as the preliminary details
regarding our work on a 3-D passive mmW simulator capable of true physical polarization dependent effective
emissivity and reflectivity rendering, based on the open-source Blender engine.
