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Proceedings Paper

Holographic Principles Applied To Low Frequency Electromagnetic Imaging In Conductors
Author(s): B. P. Hildebrand; A. J. Boland; T. J. Davis
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Paper Abstract

Low frequency electromagnetic methods for non-destructive testing have been interpreted in terms of the eddy current or inductive phenomenon. In this scenario the flaw distorts the flow of eddy currents, which in turn, results in a change of impedance of the sensing coil. This change of complex impedance can be analyzed in terms of phase an amplitude, and inferences about the depth and size of the flaw made by observing the impedance plane plot on an oscilloscope as the coil is scanned across the flaw. A great deal of operator experience is required, although attempts at automating the decision making process have recently been made. In this paper we explore an alternate view-point; that the change in sensing coil impedance is due to the interference of a reflected electromag-netic wave (by the flaw) with the outgoing wave. This allows us to utilize those properties of wave theory which form the basis for holographic imaging. In this paper we show theoretically and experimentally that such is indeed the case.

Paper Details

Date Published: 15 April 1983
PDF: 8 pages
Proc. SPIE 0422, 10th Intl Optical Computing Conf, (15 April 1983); doi: 10.1117/12.936127
Show Author Affiliations
B. P. Hildebrand, Spectron Development Laboratories, Inc. (United States)
A. J. Boland, Spectron Development Laboratories, Inc. (United States)
T. J. Davis, Spectron Development Laboratories, Inc. (United States)

Published in SPIE Proceedings Vol. 0422:
10th Intl Optical Computing Conf
Sam Horvitz, Editor(s)

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