Millimeter-Wave and Terahertz Imaging in Security Applications

Luukanen, Arttu; Appleby, Roger; Kemp, M. C.; Salmon, Neil A.

doi:10.1007/978-3-642-29564-5_19

Cited by 57 publications

(41 citation statements)

References 82 publications

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“…241 There have also been recent studies on the direct application of terahertz spectroscopy (as opposed to imaging) to a number of potential industrial applications.…”

Section: Applicationsmentioning

confidence: 99%

Terahertz Time-Domain and Low-Frequency Raman Spectroscopy of Organic Materials

2015

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With the ongoing proliferation of terahertz time-domain instrumentation from semiconductor physics into applied spectroscopy over the past decade, measurements at terahertz frequencies (1 THz [ 10 12 Hz [ 33 cm À1) have attracted a sustained growing interest, in particular the investigation of hydrogen-bonding interactions in organic materials. More recently, the availability of Raman spectrometers that are readily able to measure in the equivalent spectral region very close to the elastic scattering background has also grown significantly. This development has led to renewed efforts in performing spectroscopy at the interface between dielectric relaxation phenomena and vibrational spectroscopy. In this review, we briefly outline the underlying technology, the physical phenomena governing the light-matter interaction at terahertz frequencies, recent examples of spectroscopic studies, and the current state of the art in assigning spectral features to vibrational modes based on computational techniques.

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“…241 There have also been recent studies on the direct application of terahertz spectroscopy (as opposed to imaging) to a number of potential industrial applications.…”

Section: Applicationsmentioning

confidence: 99%

Terahertz Time-Domain and Low-Frequency Raman Spectroscopy of Organic Materials

2015

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“…Furthermore, materials intentionally attached to the skin, having dielectric properties identical with human skin (to achieve a false negative in a security screening system), will be identified by their differential radiation temperatures, something which an active system cannot achieve, 3) the measurements can be made in tens of seconds using a non-contact sensor with high precision, and 4) the system is free from artefacts of speckle effects and multipath problems since spatially incoherent emission is used [12,13].…”

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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“…Since THz radiation exhibit good penetrating power, it can be used to obtain images of hidden objects. For this reason it is a good basis for automatic target recognition (ATR) systems [3] developed for early detection and warning of threats. Because detection of such threats is one of key issues of public places security, it is obvious the great interest in such systems.…”

Section: Fig 1 the Terahertz (Thz) Spectral Rangementioning

confidence: 99%

“…visible, THz and infrared images [3] From the above arguments it follows that the standard recognition algorithms designed for conventional images suitable for ATR will work poorly in the THz range. Therefore, the task of developing new THz image processing algorithms and techniques in the context of ATR is crucial today.…”

Section: Fig 2 Image Quality For Different Spectral Rangesmentioning

confidence: 99%

Hydrological Scenarios of the Renaissance Dam in Ethiopia and Its Hydro-Environmental Impact on the Nile Downstream

Bastawesy

2015

J. Hydrol. Eng.

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The paper presents the results of developing an algorithm for automatic target recognition in broadband (0.110) terahertz images. Due to the physical properties of terahertz radiation and associated hardware, such images have low contrast, low signaltonoise ratio and low resolutioni.e. all the characteristics of a lowcount images. Therefore, standard recognition algorithms designed for conventional images work poorly or are not suitable at all for the problem considered. We have developed a fundamentally different approach based on clustering 2D point clouds in accordance with a set of predefined patterns. As a result, we reduce the problem of target recognition to the problem of maximizing the image data likelihood with respect to the classes of model objects up to the size and position. The resulting recognition algorithm has a structure close to that of the well-known EM algorithm; its formal scheme is at the end of the paper.

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Millimeter-Wave and Terahertz Imaging in Security Applications

Cited by 57 publications

References 82 publications

Terahertz Time-Domain and Low-Frequency Raman Spectroscopy of Organic Materials

Terahertz Time-Domain and Low-Frequency Raman Spectroscopy of Organic Materials

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

Hydrological Scenarios of the Renaissance Dam in Ethiopia and Its Hydro-Environmental Impact on the Nile Downstream

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