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Accession Number ADA574102
Title Subsurface Electromagnetic Induction Imaging for Unexploded Ordnance Detection.
Publication Date 2012
Media Count 12p
Personal Author B. E. Barrowes F. Shubitidze J. P. Fernandez K. O'Neill T. M. Grzegorczyk
Abstract Detection and classification of unexploded ordnance based on electromagnetic induction have made tremendous progress over the last few years, to the point that not only more realistic terrains are being considered but also more realistic questions such as when to stop digging are being posed. Answering such questions would be easier if it were somehow possible to see under the surface. In this work we propose a method that, within the limitations on resolution imposed in the available range of frequencies, generates subsurface images from which the positions, relative strengths, and number of targets can be read off at a glance. The method seeds the subsurface with multiple dipoles at known locations that contribute collectively but independently to the measured magnetic field. The polarizabilities of the dipoles are simultaneously updated in a process that seeks to minimize the mismatch between computed and measured fields over a grid. In order to force the polarizabilities to be positive we use their square roots as optimization variables, which makes the problem nonlinear. The iterative update process guided by a Jacobian matrix discards or selects dipoles based on their influence on the measured field. Preliminary investigations indicate a fast convergence rate and the ability of the algorithm to locate multiple targets based on data from various state-of-the-art electromagnetic induction sensors.
Keywords Algorithms
Anomalies
Classification
Configurations
Convergence
Detection
Dipoles
Electromagnetic induction
Emi(Electromagnetic induction)
Ground penetrating radar
Images
Inversion
Limitations
Magnetic fields
Magnetometry
Resolution
Square roots
Subsurface
Targets
Temtads(Towed array detection system)
Terrain
Transmitters
Unexploded ammunition
Uxo(Unexploded ordnance)


 
Source Agency Non Paid ADAS
NTIS Subject Category 79A - Ammunition, Explosives, & Pyrotechnics
46 - Physics
Corporate Author Dartmouth Coll., Hanover, NH.
Document Type Journal article
Title Note Journal article.
NTIS Issue Number 1318
Contract Number W911NF-08-1-0385

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