Guilizzoni, R;
Watson, JC;
Bartlett, PA;
Renzoni, F;
(2016)
Electromagnetic Induction Imaging of concealed metallic objects by means of resonating circuits.
In: Bishop, SS and Isaacs, JC, (eds.)
Detection and Sensing of Mines, Explosive Objects, and Obscured Targets XXI.
(pp. 98230P-1-98230P-8).
Society of Photo-Optical Instrumentation Engineers: Washington, WA, United States.
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Abstract
An electromagnetic induction system, suitable for 2D imaging of metallic samples of different electrical conductivities, has been developed. The system is based on a parallel LCR circuit comprising a ferrite-cored coil (7.8 mm x 9.5 mm, L=680 μH at 1 KHz), a variable resistor and capacitor. The working principle of the system is based on eddy current induction inside a metallic sample when this is introduced into the AC magnetic field created by the coil. The inductance of the LCR circuit is modified due to the presence of the sample, to an extent that depends on its conductivity. Such modification is known to increase when the system is operated at its resonant frequency. Characterizing different metals based on their values of conductivity is therefore possible by utilizing a suitable system operated at resonance. Both imaging and material characterization were demonstrated by means of the proposed electromagnetic induction technique. Furthermore, the choice of using a system with an adjustable resonant frequency made it possible to select resonances that allow magnetic-field penetration through conductive screens. Investigations on the possibility of imaging concealed metals by penetrating such shields have been carried out. A penetration depth of δ~3 mm through aluminium (Al) was achieved. This allowed concealed metallic samples- having conductivities ranging from 0.54 to 59.77 MSm-1 and hidden behind 1.5-mm-thick Al shields- to be imaged. Our results demonstrate that the presence of the concealed metallic objects can be revealed. The technique was thus shown to be a promising detection tool for security applications.
| Type: | Proceedings paper |
|---|---|
| Title: | Electromagnetic Induction Imaging of concealed metallic objects by means of resonating circuits |
| Event: | Conference on Detection and Sensing of Mines, Explosive Objects, and Obscured Targets XXI, 17 April 2016, Baltimore, Maryland, United States |
| Location: | Baltimore, MD |
| Dates: | 18 April 2016 - 21 April 2016 |
| ISBN-13: | 9781510600645 |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1117/12.2223594 |
| Publisher version: | http://dx.doi.org/10.1117/12.2223594 |
| Language: | English |
| Additional information: | Copyright © 2016 Society of Photo-Optical Instrumentation Engineers (SPIE). One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited. |
| Keywords: | Science & Technology, Physical Sciences, Optics, Imaging, electromagnetic induction, eddy currents, material characterization, screening, Tomography, Sensor |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/1524299 |
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