4 August 2003 Pipeline flaw detection with wavelet packets and GAs
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Abstract
This paper is concerned with the detection of physical flaws on pipe walls in gas pipelines. The sensor technology is EMAT, a non-contact ultrasonic technology. One EMAT is used as a transmitter, exciting an ultrasonic impulse into the pipe wall. Another EMAT located a few inches away from the first is used as a receiving transducer. This paper reports on the identification of flaw signatures in the receiver output. The first step in flaw characterization is to perform wavelet analysis of the signature. Being non-shift-invariant, an array of coefficients of a discrete wavelet transfor of a signal is not directly suitable as a pattern recognition feature. However, comparing composite properties of the signal on different scales is useful, because the more conversion caused by a flaw, changes the composite properties of the signal in wavelet space. For EMAT data, the useful information projects onto five mutually orthogonal wavelet scales. This paper reports onteh use of a robust 17-dimensional feature vector that mutually orthogonal wavelet scales. This paper reports on the use of a robust 17-dimensional featuer vector that consistently distinguishes "flaw" signatures from "no-flaw" signatures in a substantial collection of experimental data.
© (2003) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Stephen W. Kercel, Raymond W. Tucker, Venugopal K. Varma, "Pipeline flaw detection with wavelet packets and GAs", Proc. SPIE 5103, Intelligent Computing: Theory and Applications, (4 August 2003); doi: 10.1117/12.496975; https://doi.org/10.1117/12.496975
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