New Method of Metal Magnetic Memory Signal Measuring and Denoising

摘要

The metal magnetic memory (MMM) technique can be effective in determining the initial damage of materials and structures in service and is partly applied in engineering. However, the real signals measured in engineering practice usually contain interference of the background magnetic field and measurement noise. For the influence of the background magnetic field, we designed a measuring probe constituted by two magnetic sensors that were arranged at different heights in the same vertical direction. Through the channel compensated method, we extracted principal features of the self-magnetic leakage field (SMLF) signal. As for the influence of measurement noise, we built the structure elements combined with the SMLF signal characteristic and investigated multi-scale morphological filtering to reduce the noise. The simulation and experiment results show that the proposed methods can not only suppress the background magnetic field and many kinds of noise but also protect the SMLF signal detail effectively.