数字散斑干涉术物体形变测量

Digital Speckle Pattern Interferometry for Deformation Measurement

基于数字散斑干涉术测量物体形变的原理,研究了物体面内位移及变形的测试技术.采用电荷耦合器件记录变形前后的两幅散斑图,取代传统散斑干涉术中的记录干板,省去传统方法中干板显影、定影的繁琐的化学湿处理过程.分别用菲涅尔散斑和像面散斑方法获得散斑干涉图,用相减技术得到含有物体形变信息的散斑干涉条纹.设计高斯低通滤波器,对干涉条纹进行处理,提高了干涉条纹的对比度.提出扫描条纹中心行方法,由条纹中心行一维位相分布获得一维物面变形,实现了散斑干涉条纹的自动判读.试验表明,该方法简洁且实用.

The technique of measuring displacement and deformation based on principle of digital speckle pattern interferometry was studied.Traditional recording plane in speckle pattern interferometry was substituted by charge coupled device camera.The method left out the wet chemical process of developing and fixing.The speckle patterns were obtained in two ways of Fresnel speckle method and image plane speckle method.Two patterns of speckle interference field before and after deformation were recorded by charge coupled device camera and stored in computer;after subtracting and taking the absolute value,the correlative fringe pattern including object′s deformation information was acquired.Processing the pattern with low-pass Gauss filter,the contrast of interference pattern was enhanced.The scanning central row method was proposed.From the one dimension phase distribution of central row,one dimension deformation was obtained and interference fringes interpreter was automatically realized.The experiment shows that this method is simple and available.