A Passive Millimeter-Wave Imager Used for Concealed Weapon Detection

Zheng, Cheng; Yao, Xin; Hu, Anyong; Miao, Jungang

doi:10.2528/pierb12101505

Cited by 57 publications

(42 citation statements)

References 22 publications

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“…The detection of concealed threats on the human body in transport networks and border crossings poses an international challenge for the development of effective stand-off and portal security screening systems [1,2]. The millimeter-wave (MMW) band is the region of the electromagnetic spectrum between the microwave and terahertz bands, covering the frequency ranges (30-300) GHz [3,4].…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic Signatures of Human Skin in the Millimeter Wave Band 80-100 GHZ

Owda

Salmon

Rezgui

2018

PIER B

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Abstract-Due to changes in global security requirements attention is turning to new means by which anomalies on the human body might be identified. For security screening systems operating in the millimeter wave band anomalies can be identified by measuring the emissivities of subjects. As the interaction of millimeter waves with the human body is only a fraction of a millimeter into the skin and clothing has a small, but known effect, precise measurement of the emission and reflection of this radiation will allow comparisons with the norm for that region of the body and person category. A technique to measure the human skin emissivity in vivo over the frequency band 80 GHz to 100 GHz is developed and described. The mean emissivity values of the skin of a sample of 60 healthy participants (36 males and 24 females) measured using a 90 GHz calibrated radiometer were found to range from 0.17±0.005 to 0.68±0.005. The lower values of emissivity are a result of measuring particularly thin skin on the inner wrist, volar side of the forearm, and back of hand, whereas higher values of emissivity are results of measuring thick skin on the outer wrist, dorsal surface of the forearm, and palm of hand. The mean differences in the emissivity between Asian and European male participants were calculated to be in the range of 0.04 to 0.11 over all measurement locations. Experimental measurements of the emissivity for male and female participants having normal and high body mass index indicate that the mean differences in the emissivity are in the range of 0.05 to 0.15 for all measurement locations. These results show the quantitative variations in the skin emissivity between locations, gender, and individuals. The mean differences in the emissivity values between dry and wet skin on the palm of hand and back of hand regions were found to be 0.143 and 0.066 respectively. These results confirm that radiometry can, as a non-contact method, identify surfaces attached to the human skin in tens of seconds. These results indicate a route to machine anomaly detection that may increase the through-put speed, the detection probabilities and reduce the false alarm rates in security screening portals.

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Section: Introductionmentioning

confidence: 99%

Electromagnetic Signatures of Human Skin in the Millimeter Wave Band 80-100 GHZ

Owda

Salmon

Rezgui

2018

PIER B

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“…For BHU-2D-U, the background cancelation technique has been used to reduce the influences of aliasing error and system offset [5,6]. Thus the visibility function samples need to be pre-processed before image reconstruction…”

Section: The Proposed Imaging Methodsmentioning

confidence: 99%

“…Passive millimeter-wave imagers have become popular for high resolution observation of concealed weapons detection applications [1][2][3][4][5]. Compared with X-ray or radar instruments, passive imagers receive spontaneous radiations emitted or reflected by the interested subjects.…”

Section: Introductionmentioning

confidence: 99%

Near Field Image Reconstruction Algorithm for Passive Millimeter-Wave Imager Bhu-2d-U

Yao¹,

Zheng²,

Zhang³

et al. 2013

PIER C

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Abstract-A passive millimeter-wave imager BHU-2D-U based on synthetic aperture interferometric radiometer (SAIR) technique has been developed by Beihang University. The imager is designed for detecting concealed weapons on human body and operated under the near-field condition of the antenna array, thus the conventional Fourier imaging theory does not apply. In this paper, an accurate numerical image reconstruction algorithm using regularization theory is proposed. By means of adding a prior information of desired brightness temperature image, the influences of measurement noise and focusing error on the reconstructed image have been reduced. Numerical simulations and experiments on BHU-2D-U have been performed to verify the superiorities of the proposed algorithm over the corrected Fourier method and the Moore-Penrose pseudo inverse method. The results demonstrate that the proposed method is an advantageous imaging algorithm for near-field millimeter-wave SAIR.

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“…A SAIR imager named BHU-2D [6] has been developed by Beihang University. It consists of a 48-element U-shape antenna array, and each receiver channel is composed of a mmW receiver [7][8][9] and an IF IQ demodulator.…”

Section: System-level Pn Impacts On Visibility Phase Errormentioning

confidence: 99%

Local Oscillator Uncorrelated Phase Noise Analysis for Millimeter-Wave Passive Imager Bhu-2d Frequency Synthesizer

Zhang¹,

Li²,

Zheng³

et al. 2013

PIER B

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Abstract-In this paper, a nontrivial local oscillator uncorrelated phase noise analysis is proposed for frequency synthesizer of a passive millimeter-wave Synthetic Aperture Interferometric Radiometer (SAIR) imager BHU-2D designed for concealed weapon detections on human bodies with high imaging rates. The frequency synthesizer provides local oscillator signals for both millimeter-wave front-ends and intermediate frequency I/Q demodulators for the receivers. The influence of local oscillator uncorrelated phase noise in different offset frequency ranges on the visibility phase errors have been systematically investigated, and the corresponding system-level visibility specifications are drawn. The integrated RMS phase error has been applied to set uncorrelated phase noise requirements in the most critical offset frequency range for visibility error control. The synthesizer design is given, and measurement results have proved that the visibility phase error requirement is achieved by the PN analysis method proposed with system-level visibility error tests performed. To conclude, the phase noise effects on SAIR visibility phase errors are investigated by theory, and are properly limited by the PN requirement analysis method to ensure that the system-level visibility phase error specification is satisfied.

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A Passive Millimeter-Wave Imager Used for Concealed Weapon Detection

Cited by 57 publications

References 22 publications

Electromagnetic Signatures of Human Skin in the Millimeter Wave Band 80-100 GHZ

Electromagnetic Signatures of Human Skin in the Millimeter Wave Band 80-100 GHZ

Near Field Image Reconstruction Algorithm for Passive Millimeter-Wave Imager Bhu-2d-U

Local Oscillator Uncorrelated Phase Noise Analysis for Millimeter-Wave Passive Imager Bhu-2d Frequency Synthesizer

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