Guilizzoni, R;
Watson, JC;
Bartlett, P;
Renzoni, F;
(2015)
Imaging by electromagnetic induction with resonant circuits.
In: Dhar, NK and Dutta, AK, (eds.)
Proceedings Volume 9481, Image Sensing Technologies: Materials, Devices, Systems, and Applications II.
SPIE: Maryland, United States.
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Abstract
A new electromagnetic induction imaging system is presented which is capable of imaging metallic samples of different conductivities. The system is based on a parallel LCR circuit made up of a cylindrical ferrite-cored coil and a capacitor bank. An AC current is applied to the coil, thus generating an AC magnetic field. This field is modified when a conductive sample is placed within the magnetic field, as a consequence of eddy current induction inside the sample. The electrical properties of the LCR circuit, including the coil inductance, are modified due to the presence of this metallic sample. Position-resolved measurements of these modifications should then allow imaging of conductive objects as well as enable their characterization. A proof-of-principle system is presented in this paper. Two imaging techniques based on Q-factor and resonant frequency measurements are presented. Both techniques produced conductivity maps of 14 metallic objects with different geometries and values of conductivity ranging from 0.54х106 to 59.77х106 S/m. Experimental results highlighted a higher sensitivity for the Q-factor technique compared to the resonant frequency one; the respective measurements were found to vary within the following ranges: ∆Q=[-11,-2]%, ∆f=[-0.3,0.7]%. The analysis of the images, conducted using a Canny edge detection algorithm, demonstrated the suitability of the Q-factor technique for accurate edge detection of both magnetic and non-magnetic metallic samples.
| Type: | Proceedings paper |
|---|---|
| Title: | Imaging by electromagnetic induction with resonant circuits |
| Event: | Conference on Image Sensing Technologies - Materials, Devices, Systems, and Applications II |
| Location: | Baltimore, MD |
| Dates: | 22 April 2015 - 23 April 2015 |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1117/12.2183180 |
| Publisher version: | http://doi.org/10.1117/12.2183180 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Imaging, electromagnetic induction, eddy currents, material characterization |
| 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.ucl.ac.uk/id/eprint/1498349 |
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