【作者】 郑刚；

【导师】 王文格；

【作者基本信息】 湖南大学 ， 机械电子工程， 2004， 硕士

【摘要】 光学非接触式三维形面测量技术是光学、图像与视觉检测的一个重要分支，它在产品质量控制、机器视觉、医学诊断等方面有着极其广泛的应用前景。但是，如何快速准确地获取被测物体三维形面的技术现在仍然是一项重要而困难的研究课题。本文提出一种基于数字条纹投影与数字相移技术的三维形面测量系统。与传统相移系统相比，主要从两方面提高了系统的测量精度：第一，新的数字投影系统可以产生具有高亮度与高对比度的标准正弦投影条纹，从而提高系统的分辨率与测量精度。第二，利用计算机软件精确控制条纹相移，避免传统相移系统引入的各种误差。 在图像预处理方面，并非单纯采用常用滤波方法滤除随机噪声。本文根据投影条纹图的特性，采用旋滤波方法滤除投影条纹图中的随机噪声，同时不损害条纹信号的重要信息。此外，尝试对实际条纹图进行正则化处理，尽量抑制条纹幅值变化与背景变化等系统噪声。 在相位提取与相位去包裹方面，采用相移法提取相位主值图，并首次提出基于去包裹可靠性的相位去包裹方法。此算法采用排序的方法，将像素点按一定的可靠性选择标准排序放入队列，并以此序列进行相位去包裹。与传统方法相比，能够自动避开噪声，解决相位去包裹中阴影遮挡以及空洞等问题，克服了传统去包裹方法中的误差传播效应，准确快速地对全场进行相位去包裹。 最后通过对平面的测量实例分析投影条纹的周期与相移次数对测量精度的影响，同时以佛像头和吸尘器模型为例分折比较洪水相位去包裹方法和基于可靠性的相位去包裹方法。更多还原

【Abstract】 The non-contact 3-D shape measuring method is an important branch of Optics, image processing and computer vision, which has a wide and urge application in the fields of product quality inspection machine vision medicine and so on. However it is an important but difficult problem to device a technology which can be used to measure 3D surface of a object nicely and rapidly. A method based on digital fringe projection and digital phase shifting technique is proposed in this thesis for 3D shape measurement.Compared to the traditional grating fringe projection systems, the new system has the following two major advantages. Firstly, with the new digital projection system, the standard sinusoid fringe patterns with exceptionally high brightness and contrast can be projected, thus improving the accuracy of surface contouring. Secondly, purely software-based digital phase shifting the fringe can be applied to improve the resolution of the contouring technique and eliminate the noise with the traditional phase-shiftingtechnique.Based on the character of projected fringes, some spin-filter methods can be creatively applied to eliminate the random-noise in the projected fringes which is not purely eliminated by the traditional digital image preprocessing, and not to damage the importance information of projected fringes. In additional, noised-free normalized fringe patterns can be established from the projected fringe patterns.For the phase wrapping and phase unwrapping research, phase shifting algorithms can be used to calculate phase map, and a new algorithm for phase unwrapping of phase map is originally proposed. It is based on the use of a queue for the processing of arbitrary shapes and the Phase reliability for the pixels to be processed. Compared with traditional phase unwrapping algorithm, it can bypass the noise automatically, solve the problem of the shade sheltering or cavity and overcome the error propagation problem.By the data processing of the experiment, some results are presented to show the influence on the precision of measuring exerted by the period of the projected fringe and the steps of phase shifting, and the performance of the Phase unwrapping algorithm based on the reliability in comparison with flood phase unwrapping algorithm.更多还原