Correlation canceling principle used in pipeline head inspection

Magnetic flux leakage (MFL) is—concerning the detection of surface-near and surface-braking defects—the most commonly used method in inspecting steel pipelines after production and in service. In this paper, we attempt to use a new method based on MFL to inspect pipeline heads. We introduce the idea of a generalized characterization of the leading pipeline (in the joining region) in order to define a reference signal of a flaw, and discuss the method of separating the MFL signal of a superimposed defect near pipeline heads. The difference between reference signal and artificial flaw signal can be extracted properly by using the methodology of correlation canceling.