基于数字图像相关方法的面内位移测量的研究与应用

发布时间：2018-06-21 02:22

本文选题：数字图像相关 + 面内位移测量　；参考：《郑州大学》2017年硕士论文

【摘要】：数字图像相关方法(DICM)是传统光学测量技术与现代数字图像处理技术相结合的产物。与其他测量方法相比,数字图像相关法具有突出的优越性,以其光路简单、非接触、精度高等优点,已在材料测试、土木工程、机械制造等传统领域,甚至是航空航天、纳米科学、生物力学等高精尖领域都得到了广泛的应用,是现代实验力学中最活跃、最重要、应用最广泛的光测方法之一。数字图像相关方法是通过对物体表面变形前后的散斑图像进行搜索匹配来计算物体表面的位移场或应变场。数字图像相关方法中八个关键问题即:1、相关系数函数;2、整像素搜索方法;3、亚像素搜索算法;4、散斑图;5、减噪;6、补偿技术;7、位移场到应变场间的转换;8、三维应变场。目前,国内外对数字图像相关方法的研究主要集中在两个方面:1、计算效率;2、测量精度。而本文正是基于对这两方面问题的探讨和改进,深入的研究了数字图像相关方法在面内位移测量上的基本原理、相关系数、整像素搜索方法及亚像素搜索算法。在完成整个搜索匹配工作的基础上,还对相关系数以及亚像素搜索的计算过程进行了改进,并编写了相关运算程序对其进行验证。在计算效率方面,本文首先分析了匹配搜索过程中常见的六种相关系数函数,对其各方面的运算性能进行了对比并提出了几点可以提高计算速度的办法,行之有效的缩短了匹配时间。然后介绍了几种常见的整像素搜索算法,通过理论分析以及仿真模拟验证得出,三步搜索法的匹配效果较好、计算速度较快且易于编程。在测量精度方面,结合灰度插值法和曲面拟合法这两种算法的性能及优点,本文提出了一种新的改进的亚像素搜索算法—拟合插值结合算法,并对其在亚像素位移搜索上的测量精度和抗噪能力做了验证。最后,基于MATLAB软件编写了二维数字图像相关计算程序,并通过悬臂梁弯曲实验和刚体平移实验验证了本文提出的拟合插值结合算法以及DICM计算程序在实际应用中的可行性及准确性,实验结果精确度比较高。
[Abstract]:Digital image correlation method (DICM) is the product of traditional optical measuring technology and modern digital image processing technology combined. Compared with other measurement methods, the digital image correlation method has prominent advantages, with its simple optical path, non-contact, high precision, has material testing, material in civil engineering, the traditional field of machinery even manufacturing. Is the aerospace, nano science, biomechanics and other high-tech fields have been widely used, is the most active, the most important in modern experimental mechanics, one of the most widely used optical method. Digital image correlation method is used to calculate the displacement field matching surface or by speckle image on the surface before and after deformation is made Strain field. Eight key problems in digital image correlation method is: 1, the correlation coefficient function; 2, integer pixel search method; 3, sub-pixel search algorithm; 4, speckle pattern; noise reduction; 5, 6, 7, compensation technology; displacement field to the strain field between 8 and three; strain field. At present, domestic and foreign research on digital image correlation method mainly focus on two aspects: 1 And the computational efficiency; 2, the accuracy of measurement. And this paper is on the two issues of discussion and improvement based on the basic principle, the study of digital image correlation method in plane displacement measurement on the correlation coefficient, the integer pixel search method and sub-pixel search algorithm. Based on complete search work also, the correlation coefficient at The calculation process and the sub-pixel search is improved, and the preparation of the relevant operational procedures to verify the results. The efficiency of calculation, this paper first analyzes the matching six correlation coefficients of common function in the search process, the operation of the performance was compared and proposed several points can improve the calculation speed for the way, Shorten the matching time. And then introduces several common integer pixel search algorithm, through theoretical analysis and simulation verify that the better matching effect of three step search method, fast calculation speed and easy programming. In terms of measurement accuracy, combined with gray interpolation method and fitting the legal properties and advantages of these two algorithms, This paper presents a new improved Sub-pixel Search algorithm combined with interpolation algorithm, and its accuracy in the sub-pixel displacement measurement and search on the anti noise ability is verified. Finally, the MATLAB software is written based on two-dimensional digital image correlation calculation program, and through the cantilever beam bending experiment and translational experiment to verify the This paper combined the proposed interpolation algorithm and the feasibility and accuracy of DICM in the practical application of the calculation procedure, the experimental results with high accuracy.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP391.41

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