Active Millimeter Wave Sensor for Standoff Concealed Threat Detection

Abstract

We present a millimeter radar for threat level evaluation developed for the detection concealed threats, such as guns and person borne improvised explosive devices (PBIED). The system uses a Gaussian optic lens antenna to achieve standoff ranges up to 25 m. Ultra-wideband swept frequency radar, using direct detection receivers, is implemented to achieve short radar range resolution (< 10 mm). The system is capable of detecting a wide range of objects positioned in front of the body by interpretation of the scattered waveform. Threat detection is rendered autonomously by a neural network that processes the scattered polarimetric, depth domain radar waveforms. The system may be configured to alarm or reject certain classes of objects, allowing for the detection of specific or broad spectrum threats. The radar system is portable and manually steered by the operator to enable standoff monitoring of walking human targets in real time. A video feed provides the operator with a wide field of view that allows tracking of persons and greatly facilitates aiming of the sensor. Rapid (1 ms) radar sweep times and fast signal acquisition and processing are implemented to provide threat detection at video frame rates (30 fps). Performance parameters for the detection of hand-guns and simulated PBIED are presented for ranges up to 25 m.

Experimental determination and simulations of the Huynen target parameters for full polarimetric millimetre wave concealed weapon recognition

“…This work continues the investigation into coherent full polarimetric radar techniques to maximise acquired information content from scenarios where spatial information content is fundamentally limited due to the effects of effects [1]. In a stand-off security screening scenario millimetre wave techniques have the advantage of being able to penetrate clothing and potential to detect concealed weapons such as person born improvised explosive devices (PBIED) and knives both of metallic or ceramic construction [2], [3], [4], [5], [6], [7]. Target detection using circular polarisation has been trialled [8] and full polarimetry for security screening was initially investigated in [9], [10] using a pseudo monostatic (transmitter and receiver co-located).…”

CNN with Pose Segmentation for Suspicious Object Detection in MMW Security Images

“…For example, X-rays harm the human body, arched metal detectors only discern metal objects, and manual inspection poses the risk of personal discomfort. The millimeter-wave (MMW) three-dimensional imaging scanner [ 2 , 3 , 4 , 5 , 6 , 7 ] based on the near-field synthetic aperture radar (NF-SAR) three-dimensional imaging technology [ 8 , 9 , 10 , 11 ] offers an alternative. When compared with the traditional security-check measures, the MMW three-dimensional imaging scanner can provide the following advantages: 1.…”

Review of Active Millimeter Wave Imaging Techniques for Personnel Security Screening

“…In 2013, Andrews et al presented a mmW radar using a Gaussian optic lens antenna for concealed threats detection. The radar system is portable and manually steered by the operator to enable up to 25 m standoff distance for monitoring walking human targets at video frame rates [18]. Imaging radar using multiple receiver arrays in the focal plane of the imaging optics has possible real time operation and relative compactness.…”

“…The proposed method could suppress harmful speckles, and render the shape of the object more clearly. In 2013, Andrews et al designed a linearly polarized 75∼110 GHz 25 m standoff mmW system with a Gaussian optic lens antenna, with the receivers only measured the power of the signals scattered by the target [18]. The system was portable and detected on-the-move human targets at 30 fps video frame rates.…”