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Proceedings Paper

Information Fusion Methods For Coupled Eddy-Current Sensors
Author(s): Kristina H. Hedengren; Kenneth W. Mitchell; David E. Ritscher
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Paper Abstract

Though imaging techniques have been applied routinely for visual, x-ray, and ultrasound inspections, they are new to eddy-current testing. Over the past few years, such techniques have been developed and applied to eddy-current data to demonstrate their value for defect detection and system analysis. In eddy-current testing, changes are sensed in the impedance of a coil excited by an alternating current to detect surface defects in metal. In eddy-current imaging, a complex impedance is measured at each pixel and used to construct an image pair. Eddy-current measurements can also be made using multiple coils; this paper discusses complex impedance image pairs formed using coupled coils that provide information from the surface covered by the two coils. A phasor plot, which is a scatter diagram of the complex impedance image pair, is an effective tool for presenting, explaining, and analyzing the information. In these plots a defect and the background noise often map to different loci, and thus have distinct signatures. The phasor plot can be used to find an appropriate combination of the image pair to improve defect detection. This paper discusses the presentation and fusion of the two images for enhanced defect detection. Images are shown together with their phasor plots to demonstrate the effects of rotational transformations and different signal combinations. The described methods are generic and can also be applied to image pairs created by different modality imaging systems; this is demonstrated with a combined eddy-current and ultrasound pair of images.

Paper Details

Date Published: 1 March 1990
PDF: 12 pages
Proc. SPIE 1198, Sensor Fusion II: Human and Machine Strategies, (1 March 1990); doi: 10.1117/12.969987
Show Author Affiliations
Kristina H. Hedengren, General Electric Corporate Research and Development (United States)
Kenneth W. Mitchell, General Electric Corporate Research and Development (United States)
David E. Ritscher, General Electric Corporate Research and Development (United States)

Published in SPIE Proceedings Vol. 1198:
Sensor Fusion II: Human and Machine Strategies
Paul S. Schenker, Editor(s)

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