“…MFL ILI tools used to detect, locate, and size pipeline anomalies, such as metal loss, dents, and ferrous metal objects, are based on the change of magnetic flux leakage in air near the pipe wall detected by the hall sensor (shown in Figure 2) [17][18][19]. Though it will be affected by piping stress deformation, cleanness of pipeline, lift off of probe, and the vibration when tool running, the accuracy and resolution of this technology is industrially accepted and world-widely used [20,21].…”