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Enhanced metal detection using Halbach arrays
Author(s): Joseph A. French; Zachary R. Brong; Daniel Winker
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Paper Abstract

The following work details a novel enhancement to metal detector coil designs with the intent of advancing the state of the art for large-scale, free-flowing threat detection in pedestrian traffic. The enhancement is achieved by increasing the signal-to-noise ratio through shaping the magnetic field and concentrating the magnetic flux to one side. Commercial metal detectors used for security suffer from decreased range and sensitivity when operated in the vicinity of benign metallic objects (e.g. rebar, metal studs, fencing, electrical wires, etc.) that generate unwanted signals. A Halbach array design provides passive enhancements by increasing the relative flux density in the direction of interest with limited additional supporting electronics. Halbach array coils were characterized and compared with single pulse induction coils for changes in performance. Comparisons of power consumption, magnetic flux density, signal-to-noise ratio, and detection range showed a 2X increase in performance of rejecting nearby benign metallic objects performance with a 25-40% loss in power efficiency to generate a magnetic field. Through these findings, metal detection designers can optimize their systems for the local metallic environment while simultaneously improving detection performance with minimal additional hardware and power requirements to advance large-scale free-flowing metal detection for crowds.

Paper Details

Date Published: 10 May 2019
PDF: 11 pages
Proc. SPIE 11012, Detection and Sensing of Mines, Explosive Objects, and Obscured Targets XXIV, 1101214 (10 May 2019); doi: 10.1117/12.2519399
Show Author Affiliations
Joseph A. French, Johns Hopkins Univ. Applied Physics Lab., LLC (United States)
Zachary R. Brong, Johns Hopkins Univ. Applied Physics Lab., LLC (United States)
Daniel Winker, Johns Hopkins Univ. Applied Physics Lab., LLC (United States)


Published in SPIE Proceedings Vol. 11012:
Detection and Sensing of Mines, Explosive Objects, and Obscured Targets XXIV
Steven S. Bishop; Jason C. Isaacs, Editor(s)

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