Journal ArticleDOI
Sensitivity maps for metal detector design
P.P. Silvester,D. Omeragic +1 more
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TLDR
Eddy-current or permeability-contrast based metal detectors may be characterized by static sensitivity maps, a new graphic representation that maps detector response to a standardized infinitesimal object in a static field.Abstract:
Eddy-current or permeability-contrast based metal detectors may be characterized by static sensitivity maps, a new graphic representation that maps detector response to a standardized infinitesimal object in a static field. A sphere is shown to be a suitable standard object because its behavior describes, to within multiplicative constants, objects of arbitrary conductivity and permeability. Static sensitivity maps take full account of both the excitation and detection coil shapes. They are compact, easy to understand, closely related to industrial testing procedures, and likely to prove a useful design tool. Their usefulness is illustrated by examples based on a metal detector for which published data exist.read more
Citations
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Journal ArticleDOI
On the Low-Frequency Electromagnetic Responses of In-Line Metal Detectors to Metal Contaminants
TL;DR: The approximated responses of sphere and wire samples from the proposed solutions agree well with the measured responses from in-line metal detectors and in theory, the approximation method on metal wire samples is also applicable to the metal contaminants of other shapes.
Journal ArticleDOI
Modeling the Response of Electromagnetic Induction Sensors to Inhomogeneous Magnetic Soils With Arbitrary Relief
TL;DR: A general model to compute the response of an electromagnetic induction sensor to a magnetic soil, in both time and frequency domains, is developed and, for most soils of relevance to mine clearance, the corresponding error is negligible.
Journal ArticleDOI
On the magnetic polarizability tensor of US coinage
John L. Davidson,Omar A. Abdel-Rehim,Peipei Hu,Liam A Marsh,Michael D. O'Toole,Anthony Peyton +5 more
TL;DR: In this paper, a method of coin characterization based on the spectroscopic response of the absolute tensor was presented, which is applied to an uncirculated set of US coins.
Journal ArticleDOI
Comparative Study of Planar Coil EMI Sensors for Inversion-Based Detection of Buried Objects
TL;DR: Zhang et al. as discussed by the authors evaluated inversion performances of two categories of planar coil sensors; single-receiver sensors used in conventional metal detection (MD), and multireceiver sensors aimed at metal characterization (MC), and concluded that relatively simple planar MC sensors clearly outperform conventional MD sensors, especially at greater depths.
Journal ArticleDOI
Determining the Electromagnetic Polarizability Tensors of Metal Objects During In-Line Scanning
TL;DR: The general approach to determining the tensor during in-line scanning is introduced and it is suggested that tensor inversion is possible for the 2-D raster scan, but not for a single line scan.
References
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Journal ArticleDOI
Analysis of an electromagnetic induction detector for real-time location of buried objects
TL;DR: In this article, the spatial response characteristics of an electromagnetic induction sensor as it passes over a metallic object are investigated using a simple analytical technique, which is illustrated with both numerical and experimental data.
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Time Domain Response of a Sphere in the Field of a Coil: Theory And Experiment
TL;DR: In this paper, the anomalous vector potential due to a conducting permeable sphere in the field of a current-carrying loop is derived and the corresponding step response is then used to obtain analytical expressions for the voltage induced in a second loop due to chosen exciting current pulse train.
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Calculation of optimum spacing for a three coil axially symmetric metal detector
M. Brighton,M.J. English +1 more
TL;DR: In this paper, a three-coil axially symmetric design is used for in-line metal detectors and a formula is derived which predicts the signal produced by a metal sphere when moved along the axis of such a detector and from this a graph is produced to determine the optimum coil spacing.
Journal ArticleDOI
Coupling between Two Antennas Separated by a Planar Interface
David A. Hill,Kenneth H. Cavcey +1 more
TL;DR: In this article, the plane-wave spectrum technique is used to analyze the coupling between a pair of antennas separated by a planar interface, where multiple reflections between the antennas or between either antenna and the interface are included in the formulation.
Electromagnetic detection of metallic particles
TL;DR: In this paper, the effect of a conducting permeable spherical particle on the impedance of a solenoid is calculated, and consideration given to maximising the effect for detection purposes.