基于傅里叶变换相位的散斑照相测面内位移算法研究

发布时间：2019-05-18 21:45

【摘要】：微小位移量测量在工程应用和材料力学中具有重要意义。现有测量技术主要分为光学测量和电学测量。而光学测量中,散斑照相法是实现微小位移量的有效途径之一。本文在现有散斑照相术理论的基础上,以提高测量精度、实现亚像素测量为目标,提出了基于傅里叶变换相位的新算法。文中对新算法运算模式进行了详细讨论,具体工作内容包括:(1)基于傅里叶变换相位的散斑照相算法理论的阐述,与传统自相关散斑照相法进行了测量极限、测量精度方面的具体对比。(2)用MATLAB编写软件完成散斑图数据处理,对比了传统相加模式、相减模式和相位算法的测量结果。(3)理论说明并验证了相位算法可以达到的测量极限和测量精度,对亚像素测量中遇到的噪声问题进行了有效处理。(4)完成了将新算法用于白光散斑测量位移的实验。理论和实验验证表明,相位算法可以检测的最小位移量与散斑尺寸无关,仅取决于光电转换器件的像元间距大小,测量最大值大于传统散斑照相法。相位法可以方便地判断散斑场移动方向。另外,相位算法可实现亚像素测量,测量精度达到亚微米级,相对误差在10%左右。白光散斑实验证明相位算法在该邻域同样适用。
[Abstract]:Micro displacement measurement is of great significance in engineering application and material mechanics. The existing measurement technology is mainly divided into optical measurement and electrical measurement. Speckle photography is one of the effective ways to realize micro displacement in optical measurement. In this paper, based on the existing speckle photography theory, a new algorithm based on Fourier transform phase is proposed in order to improve the measurement accuracy and realize the sub-pixel measurement. In this paper, the operation mode of the new algorithm is discussed in detail. The concrete work includes: (1) the theory of speckle photography algorithm based on Fourier transform phase is expounded, and the measurement limit is measured with the traditional autocorrelation speckle photography method. The specific comparison of measurement accuracy. (2) the speckle pattern data processing is completed with MATLAB software, and the traditional addition mode is compared. The measurement results of subtraction mode and phase algorithm. (3) the measurement limit and accuracy of phase algorithm are explained and verified theoretically. The noise problem encountered in sub-pixel measurement is effectively dealt with. (4) the experiment of using the new algorithm to measure the displacement of white light speckle is completed. The theoretical and experimental results show that the minimum displacement detected by the phase algorithm has nothing to do with the speckle size, but only depends on the pixel spacing of the photoelectric conversion device, and the maximum measured value is larger than that of the traditional speckle photography method. The phase method can easily judge the direction of speckle field movement. In addition, the phase algorithm can realize the sub-pixel measurement, the measurement accuracy reaches the sub-micron level, and the relative error is about 10%. The white light speckle experiment shows that the phase algorithm is also suitable in this neighborhood.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O43

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