基于频域的数字散斑相关法研究

发布时间：2018-05-21 09:02

本文选题：频域 + 数字散斑相关法　；参考：《中国民航大学》2016年硕士论文

【摘要】：数字散斑相关技术是近年来发展起来的一种高精度的物体面内位移或形变的测量方法。该技术与其他光学测量技术相比,其光路更简单、全场范围的非接触测量以及没有干涉条纹处理环节等。因此在理论研究和实际工程中都有广泛的应用前景。基于频域的散斑相关法是数字散斑相关技术的一个重要分支,该方法弥补了传统数字散斑相关法实时性较低的问题,但另一方面由于其测量精度较低,无法满足目前实际工程对精度的需求。针对这一问题,本文对频域数字散斑相关进行了系统的研究,为了提高测量精度,提出了一种基于分形插值的频域数字散斑相关测量方法。在频域散斑相关法的基础上引入了Hanning窗函数进行滤波以及采用分形插值法使峰值定位更加精确,同时还对比了范德尔-卢格特相关器和联合变换相关器的输出结果,确定选用前者进行频域散斑相关法的匹配滤波实验。最后通过刚体平移实验对其测量精度进行评估,结果证明了该方法的可靠性。通过实验结果表明,上述方法在测量物体全场有连续的形变时,对环境要求低、测量精度高且实时性较强。在研究不连续形变时,本文提出了一种基于频域与空域相结合的数字散斑相关位移测量法。采用频域相位相关法求解整像素位移信息,然后将该信息作为反向组合高斯牛顿法的初始估计并进行亚像素位移求解。该方法通过频域法来计算子区图像兴趣点的位移和形变信息,避免了传统数字散斑相关在求解初值时逐行逐列的搜索。经实验验证,该方法与牛顿迭代法相比具有更高的精确度和更快的计算速度。
[Abstract]:Digital speckle correlation (DSPR) is a highly accurate measurement method for in-plane displacement or deformation of objects. Compared with other optical measurement techniques, this technique has simpler optical path, full field non-contact measurement and no interference fringes processing. Therefore, it has a wide application prospect in both theoretical research and practical engineering. Speckle correlation method based on frequency domain is an important branch of digital speckle correlation technology. This method makes up for the low real-time performance of traditional digital speckle correlation method, but on the other hand, because of its low measurement accuracy, Can not meet the actual engineering accuracy requirements. In order to improve the measurement accuracy, a frequency domain digital speckle correlation measurement method based on fractal interpolation is proposed. Based on the frequency-domain speckle correlation method, the Hanning window function is introduced to filter and the fractal interpolation method is used to make the peak location more accurate. At the same time, the output results of the van der Lugt correlator and the joint transform correlator are compared. The former is selected for the matched filtering experiment of speckle correlation in frequency domain. Finally, the accuracy of the method is evaluated by the rigid body translation experiment, and the reliability of the method is proved. The experimental results show that the method has the advantages of low environmental requirements, high accuracy and high real-time performance when there is a continuous deformation in the whole field of the object. In this paper, a digital speckle correlation displacement measurement method based on frequency domain and spatial domain is proposed to study discontinuous deformation. The frequency domain phase correlation method is used to solve the whole pixel displacement information, and then the information is used as the initial estimation of the inverse combination Gao Si Newton method and the subpixel displacement is solved. The frequency domain method is used to calculate the displacement and deformation information of the subregion image interest points, which avoids the traditional digital speckle correlation search line by line when solving the initial values. Experimental results show that this method has higher accuracy and faster calculation speed than Newton iterative method.
【学位授予单位】：中国民航大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TP391.41

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