LS-SVMs-based reconstruction of 3-D defect profile from magnetic flux leakage signals
- 1 September 2007
- journal article
- Published by British Institute of Non-Destructive Testing (BINDT) in Insight - Non-Destructive Testing and Condition Monitoring
- Vol. 49 (9), 516-520
- https://doi.org/10.1784/insi.2007.49.9.516
Abstract
Magnetic flux leakage techniques are used extensively to detect and characterise defects in natural gas and oil transmission pipelines. Based on the least squares support vector machines (LS-SVMs) technique, this paper presents a novel approach for the three-dimensional (3-D) defect profile reconstructed from magnetic flux leakage signals. The basic theory of LS-SVM for function estimates is given. The hyper-parameters of the LS-SVMs problem formulations are tuned using a 10-fold cross validation procedure and a grid search mechanism, and applying the pruning algorithm to impose sparseness on the LS-SVMs. The training data are composed of the measured and simulated data. A mapping from MFL signals to 3-D profiles of defects is established, the reconstruction of 3-D profiles of defects from magnetic flux leakage inspection signals is achieved and 3-D error of reconstruction results is analysed. The experimental results show that the LS-SVM has high precision, good generalisation ability and capability of tolerating noise.Keywords
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