基于ESPI技术的物体缺陷自动识别技术

电子散斑干涉技术是变形和缺陷检测的重要技术方法,具有非接触、动态特性好、灵敏度高等优点.在缺陷检测中,以变形为载体,通过变形分布上的异常判别缺陷是否存在和大致位置.在这个过程中,如何摆脱人的主观判断,实现缺陷的自动识别,一直是一个技术难点.本文以实现缺陷自动识别为目标,探讨了电子散斑干涉技术的物体缺陷识别技术.总结了ESPI实现系统和变形测量的主要算法,包括时域相移干涉仪中算法、空域载波相移干涉仪中算法及空域相移干涉仪中算法,分析了各自的特点并进行了归类.描述了变形与缺陷之间的关系.讨论和总结了缺陷的时域识别方法和空域识别方法.分析了基于变形梯度的缺陷识别方法,并进行了改进.改进的方法引入了调节因子,提高了缺陷区与非缺陷区之间的界限,从而提高了该方法的缺陷识别能力.

Automatic defect detection based on ESPI

Electronic speckle pattern interferometry(ESPI) is an important technique for deformation and defect detection,it has the characters of non-contact,automation,high sensitivity.In the process of defect detection,taking the deformation as the carrier,one can judge the existence and position of defects through the abnormity in the deformation map.But how to realize its automatic recognition in the process is always a technique difficulty in the recent years.Aiming at realizing defect automatic recognition,the paper discusses the defect detection based on ESPI.It summarizes ESPI systems and main algorithms of deformation measurement,including the algorithms of temporal phase-shifting interferometer,spatial carrier phase-shifting interferometer and spatial phase-shifting interferometer.Then it analyzes their characters and sorts them out.It describes the relationship between the deformation and the defect,discusses in detail the temporal and spatial ways of defect recognition.At last it presents the revised algorithm of defect recognition based on deformation gradient.The new algorithm induces the modulus,improves the critical position between the good areas and bad areas,which enhances the recognition ability.