一种铁磁管道中远场涡流的伪峰移除方法

在铁磁性管道的远场涡流检测中,由于涡流信号会从激发线圈和接收线圈处2次穿透管壁,所以同一缺陷必然影响2次远场涡流信号的传输,其在接收信号中分别体现为主峰和伪峰。主峰包含了管道缺陷的位置等信息,然而伪峰在管道的检测和评估中表现为对缺陷定位的干扰。为了排除伪峰对管道缺陷定位的干扰,给出了一种新的远场涡流伪峰移除方法,首先利用数学形态学滤波器滤除缺陷信号的基线偏移,然后提出以径向基函数拟合主峰、伪峰的数学模型,并使用NelderMead单纯型法求解该模型的参数以得到伪峰信号。仿真实验和实际数据处理结果表明,该方法具有良好的伪峰移除效果,具有一定的适用性。

A pseudo peak removing method of remote field eddy current in ferromagnetic pipelines

In remote field eddy current testing(RFECT)of ferromagnetic pipes, because the eddy current signal penetrates the pipe wall twice from the exciting winding and pick up winding, the same defec twill affect the propagation of the remote field eddy current signal twice,which leads to the appearance of two peaks in the received signal, they are called real peak and pseudo peak here. The real peak contains the useful information such as the position of the pipe defect, whereas the pseudo peak acts as a disturbance to the defect positioning in the pipeline test and evaluation. In order to eliminate the disturbance of the pseudo peak to defect positioning, this paper proposes a novel pseudo peak removing method of remote field eddy current. Firstly, mathematical morphological filter(MMF) is utilized to eliminate the baseline bias of the defect signal, then a mathematical model based on radial basis function(RBF) is introduced to fit the real peak and pseudo peak, and the Nelder Mead simplex method(NMSM) is used to solve the model parameters and obtain the pseudo peak signal. Simulation experiment and practical data processing results indicate that the proposed method possesses a decent pseudo peak removing performance and certain applicability.