基于红外热成像技术的胶接薄板内部缺陷检测

Detection Internal Defects of Bonding Sheet Based on Infrared Technology

为了探测PC胶接薄板的内部缺陷,利用脉冲闪光灯热激励方式对试件进行加热,并由红外热像仪实时监测试件表面温度场的变化,通过表面温度场的差异来显示试件的内部缺陷。但所得的红外热图像对比度不大理想。为了更精确地提取缺陷大小,采用直方图均衡化处理,以增强图像的对比度。成功提取了缺陷尺寸大小,并对其结果进行误差分析。实验结果表明:红外热成像检测技术可以直观地检测直径4 mm以上缺陷,且直径6 mm以上缺陷的检测精度较高,测量误差可以控制在10%以内。由于边缘效应的存在,靠近边缘的缺陷测量结果误差偏大。

To investigate the internal defects in PC glued sheet, the specimen was heated by pulse flash thermal excitation. Meanwhile infrared test system monitored the specimen surface temperature field in real time. According to the difference in surface temperature of the specimen, the internal defects in specimen could be displayed. However, the obtained contrast of thermal images was poor. In order to extract defects accurately, histogram equalization was used to enhance contrast. The defects size was measured and measuring error was analyzed. The results showed that infrared thermography could intuitively display defects which were more than φ4 mm, and that the detecting precision was higher for defects which were more than φ6 mm, and that measuring error could be controlled within 10%. Due to the strong edge effect, the measuring error was larger for defects dosing to the edge.