钢丝绳缺陷漏磁信号的通道均衡化方法

Channel equalization method for MFL signals of wire rope defects

为了获得更全面的漏磁分布信息,提高缺陷定量识别的精度,应用霍尔阵列传感器检测三维漏磁场.在霍尔阵列传感器的检测过程中,由于周向分布的霍尔的提离距离差异和励磁强度的不均匀性等会导致其输出信号出现相异性,为此,本文提出了一种漏磁信号基线预估和各通道峰值归一化相结合的方法,可有效补偿由于提离距离波动及励磁强度不均匀所造成的霍尔阵列传感器的通道相异性,提高了漏磁信号的信噪比及漏磁图像的对比度.实验结果表明,均衡化后的漏磁图像缺陷定量检测准确率高.

To obtain the detailed distribution of three dimensional magnetic flux leakage （MFL） from wire rope defect, and to improve the accuracy of the quantitative recognition, Hall sensor array was used to detect the three dimensional magnetic flux leakage. In the detection process, variation of lift-off, the magnetic excitation heterogeneity and other factors will cause the dissimilarity of MFL signals obtained from the Hall sensor array, which is not conducive to quantitative inversion of wire rope defects. In this paper, a method combined with baseline estimation and normalization of peak-peak value of MFL signals is presented, by which the dissimilarity of each channel is compensated and the signal-noise ration of MFL signal and the contrast of MFL image are improved. The experimental results show that the defects are inspected more accurately with the channel-equalized MFL image.