A 3-D Defect Profile Inversion Method Based on the Continuity Correction Strategy

Magnetic flux leakage (MFL) detection is widely used in the non-destructive testing of pipelines. Inversion is a key step in MFL detection, and iterative inversion based on an optimization algorithm is an effective method for constructing the 3-D profile of defects in pipelines. However, conventional inversion algorithms suffer from weak convergence ability and are prone to local optima, which can lead to significant errors in the results. To improve the algorithm’s convergence and result accuracy, this paper proposes a “continuity correction” strategy based on geometric features of defects, which examines the relative depth value of each depth point and corrects the values of implausible points. On this basis, this paper combines the secretary bird optimization algorithm (SBOA) with the differential evolution strategy and the perturbation strategy to enhance the search capability. Through an accuracy experiment and a robustness experiment on an experimental platform, it is demonstrated that the method outperforms conventional algorithms in terms of accuracy and robustness against interference when constructing the 3-D profile of defects.