基于TMR传感器的脉冲涡流C扫描成像技术研究

Research on pulsed eddy current C-scan imaging technology based on TMR sensor

针对直线结构的阵列探针存在探针越远离线圈内径位置,存在相同位置缺陷的差分信号峰值越小的问题,提出了基于TMR传感器在同一激励线圈内半圆弧“等横向间距”布置的方法,并设计了一款新型脉冲涡流C扫描成像装置。研究结果表明,对于铜板不同形状的缺陷,通过C扫描并对扫描结果进行折算和阈值分割后绘制的等高线图能够很好地复现缺陷的形状,成功实现了铜板不同形状缺陷的二维成像,进而验证了该方法的有效性和可行性。

There’s an existing problem on linear structure that, the farther the array probe is located on coil’s inner diameter, the smaller is the peak of differential signal of the same position defect. Aiming at solving this problem, this paper put forward an approach of placing the TMR sensor in the shape of semicircle with same horizontal spacing within the same excitation coil, and designed a new type of pulse vortex C-scanning imaging device. The findings suggest that, contour maps drawn after C-scanning and the conversion and threshold segmentation of scanning results could well reshape different forms of cavities on copper plate and successfully gained the 2D images of them, thus proving the effectiveness and feasibility of this approach.