A feasibility study into the screening and imaging of hand luggage for threat items at 35 GHz using an active large aperture (1.6 m) security screening imager

Bowring, Nicholas; O'Reilly, Dean; Salmon, Neil A.; Andrews, David; Rezgui, Nacer-Ddine; Harmer, Stuart

doi:10.1117/12.2030835

Cited by 1 publication

(2 citation statements)

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“…Two images taken with a well-designed system that optimizes the DoF are shown in Figure 1. It images circularly polarized radiation over the 28 GHz to 33 GHz band using a 58-channel FPA of radiometers [16], [17]. In the center of the field-of-view the spatial resolution is ~3 cm.…”

Section: A Focal Plane Array Radiometric Imagersmentioning

confidence: 99%

“…This is an example of how the DoF is limited in near-field imaging. Experimentally measured images against an anechoic background of: a) an 17.5 cm diameter, 1 cm thick sheet of beeswax [16] (inset) and b) a metal pressure cooker inside a rucksack [17], generated by a 58-channel 31 GHz millimeter-wave imaging portal. White represents higher intensities of reflected illumination radiation.…”

Section: A Focal Plane Array Radiometric Imagersmentioning

confidence: 99%

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Indoor Full-Body Security Screening: Radiometric Microwave Imaging Phenomenology and Polarimetric Scene Simulation

Salmon

2020

IEEE Access

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The paper discusses the scene simulation of radiometric imagers and its use to illustrate the phenomenology of full-body screening of people for weapons and threats concealed under clothing. The aperture synthesis technique is introduced as this offers benefits of wide field-of-views and large depths-offields in a system that is potentially conformally deployable in the confined spaces of building entrances and at airport departure lounges. The technique offers a non-invasive, non-cooperative screening capability to scrutinize all human body surfaces for illegal items. However, for indoor operation, the realization of this capability is challenging due to the low radiation temperature contrasts in imagery. The contrast is quantified using a polarimetric radiometric layer model of the clothed human subject concealing threats. A radiation frequency of 20 GHz was chosen for the simulation as system component costs here are relatively low and the attainable half-wavelength spatial resolution of 7.5 mm is sufficient for screening. The contrasts against the human body of the threat materials of metal, zirconia ceramic, carbon fiber, nitrogen-based energetic materials, yellow beeswax, and water were calculated to be ≤7 K. Furthermore, the model indicates how some threats frequency modulate the radiation temperatures by ~±1 K. These results are confirmed by experiments using a radiometer measuring left-hand circularly polarized radiation. It is also shown using scene simulation how circularly polarized radiation has benefits for reducing false alarms and how threat objects appear in canyon regions of the body, such as between the legs and in the armpits.

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Section: A Focal Plane Array Radiometric Imagersmentioning

confidence: 99%

Section: A Focal Plane Array Radiometric Imagersmentioning

confidence: 99%