Feature extraction based on the principal component analysis for pulsed magnetic flux leakage testing

Magnetic flux leakage testing is widely used in the defect inspection of ferromagnetic materials. Pulsed magnetic flux leakage (PMFL) testing technique is a new type of electromagnetic nondestructive testing technology. A new approach for defect classification by using magnetic flux leakage testing technology and principal component analysis based signal interpretation is presented. For defect classification, different features have been extracted from magnetic flux leakage signals using time-frequency analysis. The results from study show that the proposed technique can be used to classify the two types of defects: surface and sub surface discontinuities and the introduced technique are effective in the classification of defects.