【作者】 岳慧敏；

【导师】 苏显渝；

【作者基本信息】 四川大学 ， 光学， 2005， 博士

【摘要】 光学非接触三维传感是一个重要的研究课题。采用结构照明的三维传感方法,包括相位测量轮廓术(Phase Measurement Profilometry,简称PMP)、傅立叶变换轮廓术(Fourier Transform Profilometry,简称FTP)、调制度测量轮廓术(Modulation Measurement Profilometry,简称MMP)等,近年来得到了极大的关注及深入的研究。其中,PMP、FTP等基于条纹相位分析的轮廓术通过相位解调算法(相移或傅里叶变换方法)得到的相位位于(-π,π),因此为得到连续的相位分布,并进一步得到物体的高度分布,就必须进行相(?)展开。在实测得到的截断相位图中,存在有噪声、阴影以及间断点,这些无(?)点都会使基于空间坐标展开的空间相位展开方法失败或使误差传播。相位展开的困难已成为妨碍条纹投影轮廓测量走向自动化和实用化的最大障碍。 时间相位展开的基本思想是使光栅条纹的频率随着时间而变化。相比于传统的空间相位展开方法,时间相位展开方法并不在二维相位图中寻找展开(?)径,而是沿着时间轴分别对每一个像素进行相位展开,从而实现了各像素(?)相互独立的相位展开。这种方法的突出优点是可以准确测量表面不连续物(?)的轮廓,并且使得不连续物体像连续物体一样容易展开。时间相位展开是(?)位测量领域内的一种很重要的相位展开方法,被广泛应用于干涉型和结构(?)明型计量领域中,包括散斑干涉与剪切干涉计量、波长扫描干涉术、光弹(?)量、相位测量轮廓术、傅立叶变换轮廓术等领域。本论文对基于时间相位(?)开方法的三维轮廓测量进行了广泛深入的研究,主要研究成果如下: 1.基于直观的物理模型,讨论了时间相位展开方法的基本原理和算更多还原

【Abstract】 Optical three-dimensional (3D) sensing is a very important research direction. The three-dimension sensing methods with structured illumination, such as phase measurement profilometry (PMP), Fourier transform profilometry (FTP), and modulation measurement profilometry (MMP), have received great attention in recent years. The profilometry based on fringe phase analysis such as PMP、 FTP can only return phase ranging from -π to +π by phase extraction methods(phase shifting, Fourier transforming). Phase unwrapping is necessary to recover the object shape. On a practical wrapped phase map, there are usually (?)oises、 shadows and discontinuities, witch can often make spatial phase unwrapping based on spatial coordinate fail. The difficulty in phase unwrapping has become the largest obstacle that prevents grating projection profilometry from automation and practical applications.The basic idea of temporal phase unwrapping is that the pitch of projected gratings is (?)aried over time. Compared with the spatial phase unwrapping, the temporal phase (?)nwrapping can unwrap at each pixel independently of all the other pixels in the image. The elimination of cross talk between pixels means that spatial propagation of the phase errors is prevented. The outstanding advantage of the method is that it can measure the shapes of discontinuous object, and it can unwrap the discontinuous object easily as the continuous object. So temporal phase unwrapping is an important methods in the field of phase measurement, and it has been applied widely in interferometry and structured illumination, ncluding speckle interferometry, shearography, wavelenth scanning interferometry, photoelasticity, PMP, FTP and et al. This dissertation focuses on the three-dimensional profilometry based on temporal phase unwrapping. The main results obtained can be summarized as follows:1. Based on an intuitionistic physical model, we discussed the basic principle and the phase unwrapping algorithm designing. Then we also compared several main temporal phase unwrapping on the aspects of data acquisition time, computation time and standard deviation. At last we analyzed and gave comments on the new development and its application.2. Several typical temporal phase unwrapping are analyzed by experiment. From the analysis we proposed a different method of height coordinates calibration based on temporal phase unwrapping. To recover the continuous phase distribution of all steps with the same height, and tu adjust the fitted phase surfaces of three virtual calibration planes to their ideal positions relative to the reference plane, reversal exponential temporal phase unwrapping is adopted. The propose method avoid the complicated iterative process of the former method. The experimental results prove that the proposed method is effective and feasible.3. The method of determining the proper frequency range of low-frequency grating was proposed. Frequency-Optimize of two-frequency phase measuring profilometry with low-frequency grating of different frequency and temporal- noise was analyzed theoretically and simulated numerically. It is significant especially for the reconstruction of discontinued objects.4. We have a further study about composite phase measuring profilometry(CPMP) which only one such composite grating can recover the depth. And we compare CPMP with PMP on the aspects of experiments and theories. The measurement precision and application range of CPMP is illuminated It is significant for the application of composite phase measuring profilometry.5. A novel method is proposed, in which a composite grating is projected. The composite grating is formed by modulating two separate fringe patterns with π phase difference along the orthogonal direction of the two distinct carrier frequencies. The method can eliminate zero frequency by using only one fringe pattern. The experiments show that there is no distinct decrease in the precisionof the novel method compared with the traditional π phase shifting technique. So, the novel method can allow for real time and high-speed更多还原