基于快速扫描相移算法的三维形貌测试仪开发

发布时间：2018-04-06 01:17

本文选题：相移法　切入点：扫描测量　出处：《山东大学》2017年硕士论文

【摘要】：光学三维形貌测量技术因具有非接触、精度高、易于实现自动化等特点而获得广泛的应用。为了能够满足实际测量的需要,大量的光学三维形貌测量系统和仪器被开发设计;虽然这些仪器能满足一定的测量要求,但其结构较为复杂,成本较高,测量精度较低、实时性差从而严重制约了大规模的应用。因此,设计和开发一套性能完善的三维形貌测试仪具有重要的研究意义和应用价值。本文基于相移法来进行测量,同时结合光切法的优点,采用一维扫描的方式来实现全景测量。即将投影仪和摄像机固定,待测物体放置于电动平台上,通过控制电动平台的移动来实现待测物的扫描测量;采用扫描相移算法对扫描图像的中心部分进行处理,通过相位拼接、系统标定、坐标转换来获得物体的完整形貌。设计了一套完整的基于快速扫描相移算法的三维形貌测试仪。主要内容如下:1.系统介绍了物体三维形貌测量方法,并重点对几种常用的光学三维形貌测量方法进行了分析比较,总结了它们各自的优缺点,并据此提出了本文所采用的扫描相移算法。2.对本文所采用的等步长的Stoilov算法进行了研究,分析了其存在的计算误差,并对已有的改进方法进行了相应的实验验证,找到了适合本测量系统的改进算法。同时研究了相移步长量对改进算法测量结果的影响,得出了相移步长量为π/2时,其测量结果最佳。3.详细介绍了三维形貌测量仪的基本测量原理和方法,并对扫描测量的相位提取和相位拼接方法等进行了研究,找到了适合本测量系统的相位提取和图像拼接方法。4.对该扫描测量系统的标定方法进行了研究,找到了高度和相位差之间的映射关系,详细介绍了系统标定的原理和方法,并对标定方法进行了相应的实验验证。5.基于测量原理和方法,设计了一套完整的扫描测量系统。采用C++builder编写了完整的扫描图像采集系统,实现了扫描图像的自动采集和保存。采用Matlab软件编写了图像处理程序,完成了对扫描图像的相位提取、相位展开、图像拼接、系统标定和三维显示等,实现了自动化测量。采用该系统对不同的物体分别进行了测量实验,得到了较好的测量结果,验证了测量系统的可行性。
[Abstract]:Optical 3D topography measurement technology has been widely used because of its characteristics of non-contact, high precision and easy to realize automation.In order to meet the needs of practical measurement, a large number of optical three-dimensional topography measurement systems and instruments have been developed and designed.Poor real-time performance seriously restricts large-scale applications.Therefore, the design and development of a complete set of three-dimensional topography tester has important research significance and application value.In this paper, the phase shift method is used to measure the panorama, and combined with the advantages of the optical cutting method, one dimensional scanning method is used to realize the panoramic measurement.The projector and camera are fixed, the object to be tested is placed on the electric platform, the scanning measurement of the object is realized by controlling the movement of the electric platform, and the scanning phase shift algorithm is used to process the center part of the scanning image.The complete shape of the object is obtained by phase splicing, system calibration and coordinate transformation.A complete set of three-dimensional topography tester based on fast scanning phase shift algorithm is designed.The main content is as follows: 1.In this paper, three dimensional topography measurement methods are systematically introduced, and several commonly used optical three dimensional topography measurement methods are analyzed and compared, their respective advantages and disadvantages are summarized, and the scanning phase shift algorithm. 2.In this paper, the Stoilov algorithm with equal step size is studied, the calculation error is analyzed, and the existing improved method is verified by experiments, and an improved algorithm suitable for this measurement system is found.At the same time, the influence of the phase shift step on the measurement result of the improved algorithm is studied. It is concluded that the phase shift step size is 蟺 / 2 and the measurement result is the best. 3.The basic measurement principle and method of 3D topography measuring instrument are introduced in detail, and the phase extraction and phase splicing methods of scanning measurement are studied, and the phase extraction and image stitching method suitable for this measuring system is found.The calibration method of the scanning measurement system is studied, the mapping relationship between height and phase difference is found, the principle and method of system calibration are introduced in detail, and the calibration method is verified by experiments.Based on the measurement principle and method, a complete scanning measurement system is designed.A complete scanning image acquisition system is developed with C builder, which realizes the automatic acquisition and preservation of scanned images.The image processing program is written with Matlab software, and the phase extraction, phase unwrapping, image splicing, system calibration and 3D display of the scanned image are completed, and the automatic measurement is realized.The system is used to measure different objects, and good results are obtained, and the feasibility of the system is verified.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP391.41

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