I. Introduction
Magnetic flux leakage (MFL) plays an important role in nondestructive testing (NDT) techniques and has been used in pipeline inspection gauges (PIG) for oil and natural gas pipeline inspections since the 1960s.The main part of MFL PIG is a pair of strong permanent magnets that magnetize the pipe walls axially near saturation flux density. If the wall’s thickness is reduced in the presence of a defect, a higher fraction of the magnetic flux leaks from the wall into the air inside and outside of the pipe. An array of Hall effect sensors placed around the circumference of PIG senses the leakage flux caused by anomalies in the pipe wall. Calculating the maximum safe operating pressure (MOP) is the objective of MFL data analysis. The MOP is predicted by using three geometrical parameters associated with defects features in the pipeline; length (, width (, and maximum depth (. The correct assessment of this information is vital in order to determine critical regions in the pipelines [1]–[5].