【作者】 李大伟；

【导师】 程传福；

【作者基本信息】 山东师范大学 ， 光学， 2005， 硕士

【摘要】 散斑场的研究与探测多年来在散斑干涉计量术等多个领域中一直备受关注,由于散斑场的空间分布特征包含了物体的位移和形变信息,因此可借助于散斑场的研究和探测进而获取物体的位移和形变信息。众所周知,散斑杨氏干涉条纹是干涉计量学的基础,目前杨氏干涉条纹图样已构成了许多前沿领域的基础,因此散斑杨氏干涉条纹图样的研究也具有重要意义。一般说来,散斑的性质是由散射体和散射后光波所经过的光学系统共同决定的。其中散射体所引起的光波初始随机相位起伏的剧烈程度对散斑场的概率分布等某些基本统计特性有重要影响,而光波散射后所经过的光学系统也是影响散斑场的相关和概率分布等统计特性的重要因素。然而像面散斑的理论研究目前尚未十分完善。近来研究表明利用散斑场同样可以提取随机表面的统计特性。经随机表面产生的散斑场与随机表面统计特性之间有着密切的联系,因此可通过研究散斑场的特性来提取随机表面的参量。并且散斑方法以其无接触,无损伤和成本低廉等优点已成为探测或提取随机表面信息的最重要的方法之一。此外在散斑场的实验测量中由于实验条件的限制,散斑场的测量精度总是受到限制。为了进一步提高散斑场探测的精度,我们必须克服目前探测器的分辨极限的影响。为此围绕相干散斑场的特性、探测和应用本文先后开展了一下几个方面的研究工作。第一章首先对随机表面的标定方法以及统计特性进行了描述,对比了不同特征参量的随机表面的差异。此外通过对散斑干涉计量术基本原理的分析,得到了散斑杨氏干涉条纹与物体形变之间的关系。最后剖析了散斑场探测器CCD 的基本工作原理,得到散斑图测量精度的最终限制来自于探测器本身的分辨极限的这一结论。第二章对随机表面产生的像面散斑进行了模拟和计算,讨论了像面散斑对比度与随机表面参量以及成像系统之间的关系。通过模拟获得随机表面并通过4f 系统产生了像面散斑,并计算了散斑的对比度,结果发现像面散斑对比度与成像系统参量更多还原

【Abstract】 Great attentions have been paid to the measurement and study of speckles, which hasfound profound applications in various fields such as characterizations of randomsurfaces and speckle interferometry, etc. Among all the methods for the studies ofrandom surfaces, speckle method is one of the most important owing to its advantages ofnoncontact, nondestruction and low expense. Its principle is to make use of the relationsbetween the statistical properties of the surfaces and the scattered speckle fields to extractsurface parameters. Speckle interferometry is a subject that uses the variations of thespeckle intensities to acquire the displacements or strains of an object undergoing adeformation. It is well known that analysis of speckle Young’s fringe is the foundation ofspeckle photography, and it is of great significance for the speckle interferometry. Thisdissertation focuses on the studies of the properties of speckle fields and theirmeasurements and applications. We first propose the deconvolution method to improvethe resolution in measuring speckle intensity. Then by a computational simulation, westudy the dependence of the image speckle contrast on parameters of the random surfaces.We also study the nonhomogeneity of the speckle Young’s fringes based on the statistical theoryof speckles and find the corresponding experimental evidence. This dissertation is divided intofour chapters.In chapter 1, we give an introduction to the statistical properties of random surfaces, tothe light scattering theory and the principles of the charge coupled device(CCD). We thengive a summary of the speckle interferometry and its application in the analysis ofdisplacement and strain.In chapter 2, we perform the simulational studies on the formation of image specklesand the properties of their contrast. From the results we find the dependence of speckle更多还原