数字散斑干涉形变测量中基于多CCD的相位拼接  

Phase Stitching Based Multi-CCDs Deformation Measurement in Digital Speckle Pattern Interferometry

作　　者：隆军 蔡萍[1,2] 潘淑媛 刘持越 闫浩 LONG Jun;CAI Ping;PAN Shuyuan;LIU Chiyue;YAN Hao(School of Electronic Information and Electrical Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;Shanghai Engineering Research Center for Intelligent Diagnosis and Treatment Instrument,Shanghai 200240,China)

机构地区：[1]上海交通大学电子信息与电气工程学院,上海200240 [2]上海智能诊疗仪器工程技术研究中心,上海200240

出　　处：《光子学报》2022年第4期240-247,共8页Acta Photonica Sinica

基　　金：National Key Research and Development Program of China(No. 2016YFF0200700)。

摘　　要：在数字散斑干涉测量中,对于给定尺寸的CCD,很难在不影响形变测量横向分辨率的情况下扩大视野。针对该问题,提出了一种在不影响横向分辨率的情况下拼接多个子图像相位以扩大视野的方法。设计并搭建了一套多CCD实验装置来获取多个子图像。利用重叠区域解包裹后的相位图估计相邻子图像之间的相对位置并补偿相位偏差,实现正确的相位拼接。为了使用尽可能少的CCD获得尽可能大的视野,分析了重叠区域大小对拼接效果的影响。权衡视野和精度,重叠区域的最佳尺寸约为10%。所提方法在只使用两个CCD的条件下实现了视野从5.5 cm×4 cm扩大到10 cm×4 cm。拼接前后重叠区域的最大相对误差小于1%,证明了该方法的有效性。此外,还比较了所提方法与单CCD的形变测量均方根误差(RMSE)。结果表明,提出的方法具有与单CCD形变测量接近的测量精度。Digital Speckle Pattern Interferometry(DSPI)provides an effective means of full-field and noncontact measurement of deformation or displacement. With the advancement of the aerospace and automotive industry,deformation measurements with a large Field Of View(FOV),high resolution,and wide measurement range are becoming more and more urgent. However,it is difficult to increase the FOV for a given size of CCD without compromising the lateral resolution of the deformation measurement. To solve this problem,a technique for stitching the phases of multiple sub-images to enlarge the FOV without impairing the lateral resolution was investigated. The existing aperture synthesis methods usually obtained multi-images by moving CCD or object. They are only applicable to the measurement and observation of stationary objects. For deformation measurements,at least two surface states of the object are involved,corresponding to before and after deformation. Thus,the positioning errors and axial misalignment between corresponding hologram pairs are difficult to estimate. To overcome the disadvantages of multi-step image acquisition schemes. An experimental setup with multiple CCDs was constructed to obtain multiple subimages. The phase of each CCD was extracted by the Fourier-transform method,and then the unwrapped phase maps of the overlapping areas were used to estimate the relative positions. Subsequently,the phase deviations between adjacent sub-image pairs were estimated and compensated for correct phase stitching.In order to obtain the largest possible FOV using as few CCDs as possible,the effect of the size of the overlap area on the stitching results was analyzed. The relationship between the standard deviation and the size of the overlapping area was investigated. The standard deviation is less than 0.015 μm when the size of the overlap area is between 141 and 461 pixels,corresponding to a percentage of the overlap area between8.8% and 28.8%. Therefore,the size of the overlap area is approximately 10%,which may be approp

关 键 词：数字散斑干涉 相位拼接 相位偏差 形变测量 多CCD 

分 类 号：O438.1[机械工程—光学工程]