Concealed Weapons Detection System Using Uncooled, Pulsed, Imaging Arrays of Millimeter-Wave Bolometers
Erich N. Grossman, Shalva Nolen, Nicholas Paulter, Carl D. Reintsema
We describe a system for detection of concealed weapons based upon imaging the millimeter-wave reflectance contrast between the weapon and the human body. An architecture based upon pulsed illumination and gated detection has a large advantage in sensitivity over chopped CW illumination and synchronous detection. A simple sensitivity estimate based on an assumed range at 8 m, a 30Hz frame rate, a primary collection area of 30 cm diameter, and an overall optical efficiency of 50 %, yields a noise-equivalent reflectance difference of 0.67% in a single frame. The uncooled niobium microbolometers provide a (measured) noise equivalent power of 100 pW/Hz1/2 and a time constant of 200 ns, well matched to the source pulse width and the system sensitivity requirements. Optical coupling is provided by resonant slot-ring antennas, distributed in a focal plane array covering a single mm diameter wafer. The optical and electrical systems used for coupling signals into and out of the focal array are also describe.
Proc. SPIE Conf. on Passive Millimeter-Wave Imaging Technology V
, Nolen, S.
, Paulter, N.
and Reintsema, C.
Concealed Weapons Detection System Using Uncooled, Pulsed, Imaging Arrays of Millimeter-Wave Bolometers, Proc. SPIE Conf. on Passive Millimeter-Wave Imaging Technology V, Orlando, FL, USA, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=13483
(Accessed December 7, 2023)