摘要
针对用激光局部加热试样引起的横向热流检测裂纹,对低热导率材料表面的微小裂纹成像信噪比较低的问题,提出基于相邻热信号比较的圆柱铁氧体表面微裂纹检测算法。基于几何模型重构运动的圆周表面各点热信号,以激光扫描方向相邻点热信号的欧氏距离作为特征进行成像。仿真分析确定热信号裁剪区间、参考信号位置等算法参数。对6个具有5～35μm宽度自然裂纹的样品进行实验,结果表明,在线激光2.66 mm/s的扫描速度下,裂纹成像信噪比相比常规方法提高1～2倍,可清晰成像出裂纹的形状。
Aiming at laser heating the specimen locally to detect cracks,and the signal-to-noise ratios fell when surface cracks in material with low thermal conductivity were imaged,a detection algorithm of surface microcrack which compared the adjacent thermal signals in cylinder ferrite components was proposed.The thermal signal at each position on moving cylinder was reconstructed based on geometric model,then the Euclidean distance along the laser scanning direction was used as a feature to image.The relative algorithm parameters about cutting area of thermal signal and the position of reference signal were confirmed by simulation analysis.The specimen were test,which had 5-35μm wide crack on 6 cylinder ferrite surface.The results show that this approach can enhance the signal-to-noise ratio by 1 to 2 times compared with conventional approach at the line-laser scanning speed of 2.66 mm/s,and it can image the shape of cracks evidently.
作者
王晓娜
姚行洲
侯德鑫
叶树亮
Wang Xiaona;Yao Xingzhou;Hou Dexin;Ye Shuliang(Institute of Industry and Trade Measurement Technique,China Jiliang University,Hangzhou 310018,China)
出处
《红外与激光工程》
EI
CSCD
北大核心
2018年第11期43-49,共7页
Infrared and Laser Engineering
基金
国家重大科学仪器设备开发专项(2013YQ470767)
关键词
激光热成像
相邻点热信号
欧氏距离
裂纹检测
圆柱铁氧体
laser thermography
adjacent thermal signal
Euclidean distance
crack detection
cylinder ferrite
