In the automated eddy current control installations, the noises can be reduced by using the synchronous detection on two channels with signals in quadrature, followed by a phase shifter, which allows the noise influence to be projected to one of the channels, while the useful information is obtained on the other channel. These steps are followed by different signal filterings.
This work is focused on noises reduction by using the method of minimizing the Bayes entropy [2], the processing efficiency being reached by the determination of the probability of detection and of false indication of flaws, the control operation being considered as a memoryless Markov process. A fuzzy system is proposed to reduce the noises even more.
The validity of the proposed methods has been verified for the case of eddy current inspection of wires using the rotating field method [3-5].
References
1. Grimberg, R., Olteanu, L, Cristea, T., Goia, M, Gradinariu, & Plavanescu, R, Bacanu, T.NDT International, 1990, 23, 4:201-206
2. Mohammad Djafari, A., Demoment, G. Traitement du Signal, 1988, 5, 4:235-248.
3. Savin, A., Grimberg, R., Mihalache, 0. IEEE Transactions on Magnetics, 1997, 33, 1:697-702.
4.Grimberg, R., Savin, A., Mihalache, 0., Reziescu, X, Bradu, E, Chifan, S. NDT&E International, 1995, 28, 5:297-301.
5. Grimberg, R., Savin, A., Bradu, B., MYhalache, 0., Chifan, S., Proc. 6th ECNDT, 1994, 1:213-217.
Abstract Source:
Book of Abstracts, 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN: 87-986898-0-00
Full-Text Source:
Proceedings of the 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN:
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