Active wideband 350GHz imaging system for concealed-weapon detection

Sheen, David M.; Hall, Thomas; Severtsen, Ronald H.; McMakin, Douglas L.; Hatchell, Brian K.; Valdez, Patrick Lj

doi:10.1117/12.817927

Cited by 29 publications

(20 citation statements)

References 8 publications

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“…In 2013, they continuously developed a 300-GHz system which obtained a 3.7-mm resolution [12]. Beside these two forerunners, more and more organizations started to develop their own systems and many remarkable achievements had been made [13][14][15][16][17][18][19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Terahertz Wide-Angle Imaging and Analysis on Plane-wave Criteria Based on Inverse Synthetic Aperture Techniques

Gao

Qin

Deng

et al. 2016

J Infrared Milli Terahz Waves

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This paper presents two parts of work around terahertz imaging applications. The first part aims at solving the problems occurred with the increasing of the rotation angle. To compensate for the nonlinearity of terahertz radar systems, a calibration signal acquired from a bright target is always used. Generally, this compensation inserts an extra linear phase term in the intermediate frequency (IF) echo signal which is not expected in large-rotation angle imaging applications. We carried out a detailed theoretical analysis on this problem, and a minimum entropy criterion was employed to estimate and compensate for the linear-phase errors. In the second part, the effects of spherical wave on terahertz inverse synthetic aperture imaging are analyzed. Analytic criteria of plane-wave approximation were derived in the cases of different rotation angles. Experimental results of corner reflectors and an aircraft model based on a 330-GHz linear frequency-modulated continuous wave (LFMCW) radar system validated the necessity and effectiveness of the proposed compensation. By comparing the experimental images obtained under plane-wave assumption and spherical-wave correction, it also showed to be highly consistent with the analytic criteria we derived.

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Section: Introductionmentioning

confidence: 99%

Terahertz Wide-Angle Imaging and Analysis on Plane-wave Criteria Based on Inverse Synthetic Aperture Techniques

Gao

Qin

Deng

et al. 2016

J Infrared Milli Terahz Waves

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“…THz has many advantages due to its unique electromagnetic wave band and has been found to be promising for plenty of applications, such as security and safety screening, non-destructive testing and evaluation [1][2][3][4][5][6][7]. In THz range, quasi-optics are universally used to achieve controlled propagation of radiation in free space.…”

Section: Introductionmentioning

confidence: 99%

Image reconstruction of targets illuminated by terahertz Gaussian beam with phase shift migration technique

Gao

et al. 2013

2013 38th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz)

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“…However, providing sufficient transmitter power becomes challenging at submillimeter wavelength. Presently several groups are investigating active [12] and passive [13], [14] systems, respectively. Because of the limited transmitter power and the strongly decreasing reflectance of human skin [15], passive systems are likely to achieve a better performance in stand-off scenarios.…”

mentioning

confidence: 99%

THz Absorption in Fabric and Its Impact on Body Scanning for Security Application

Knipper

Brahm

Heinz

et al. 2015

IEEE Trans. THz Sci. Technol.

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In recent years, body scanner technologies based on millimeter-wave and terahertz technologies have been shown to improve security in areas sensitive to terrorist attacks by detecting hazardous objects hidden underneath the clothing of people. Inevitably, useful devices have to provide an adequate compromise between spatial resolution limited due to diffraction and penetration through clothing. Within this context, the spectral absorption of a wide range of fabric, interference caused by the texture, and the effect of moisture within the fabric have to be considered. We have studied these effects by time-domain and Fourier transformation spectroscopy. The experimental findings are verified using a passive THz security camera operating in two frequency bands at 0.85 and 0.35 THz. The latter band was proven to be of superior use for security checks as it provides useful results even in cases of wet clothes.

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Active wideband 350GHz imaging system for concealed-weapon detection

Cited by 29 publications

References 8 publications

Terahertz Wide-Angle Imaging and Analysis on Plane-wave Criteria Based on Inverse Synthetic Aperture Techniques

Terahertz Wide-Angle Imaging and Analysis on Plane-wave Criteria Based on Inverse Synthetic Aperture Techniques

Image reconstruction of targets illuminated by terahertz Gaussian beam with phase shift migration technique

THz Absorption in Fabric and Its Impact on Body Scanning for Security Application

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