基于单帧条纹模型的相位复原技术研究

发布时间：2018-06-03 22:38

本文选题：干涉图 + 相位测量　；参考：《中国科学院光电技术研究所》2017年博士论文

【摘要】：随着现代科技工业的发展,各种先进设备都向着光机电一体化方向发展。其中,光学系统是这些复杂系统的输入或输出端口。面形精度是光学元件的核心技术指标,该指标能否达标依赖于测量所能达到的精度。干涉仪是光学元件面形检测的关键设备。干涉仪是集光机电算于一体的现代光学元件检测设备。参考表面和被测表面返回的激光光束形成干涉条纹,并通过成像系统转换为数字信息。在获取的干涉图像中,隐含着待测相位的信息。本文的主要工作就是将探测器获取的干涉条纹进行解读,完成直接测量量(干涉条纹)到最终测量信息(相位信息)的转化。为提高干涉仪对环境影响的适应能力,出现了诸如基于随机相移技术、动态干涉技术、单帧载频条纹技术的干涉仪。但这几类干涉仪都需要从硬件上对干涉仪设备进行升级。比如采用多CCD或提高干涉仪大视场成像质量等方法。为在现有干涉仪的硬件基础上,实现单帧干涉条纹的相位复原,本文提出了基于单帧干涉条纹数学模型的相位复原技术。该方法只需要采集单帧干涉条纹,不需要相移器等硬件结构和大倾斜量的特殊要求,即可达到高精度的相位复原。这样就可以实现低成本、高精度动态相位干涉测量。本文首先介绍了干涉仪的主要原理和基本的算法理论,研究了干涉图像滤波技术,特别是提出了多项式拟合滤波技术。编写了相位复原算法中的常用解包裹程序和多项式拟合程序,同时实现了移相相位算法的相位复原,并通过实验验证了算法的有效性。在对干涉仪硬件和相关算法充分调研之后,建立了单帧条纹的数学模型和优化目标函数。为了对条纹模型进行优化求解,本文中研究了牛顿迭代法和遗传算法的优化原理,分析了两种优化方法对条纹数学模型各自的求解能力,并给出了优化过程中参数边界的设置方法。根据两种优化方法各自的优缺点,提出了采用遗传算法和牛顿迭代法混合优化的模型求解方法。本文给出了条纹的优化仿真结果,该方法不但可以用于直条纹相位复原,还可以用于闭合条纹的相位复原,并通过仿真验证了优化方法的有效性。在仿真程序基础上,将实测两幅干涉图进行了相位的复原优化求解。虽然在实际的干涉条纹图中,存在着光强分布的不均匀误差和相位残差,但是通过实验验证了相位求解结果的对这类误差的不敏感性。比较了条纹优化算法给出的相位求解结果与相移方法给出的结果,两者具有面形分布和多项式系数的一致性。为分析残差对测量结果的影响,将相位拟合残差引入了优化函数中。仿真分析表明,加入相位残差后的优化迭代求解结果可以使得优化条纹与实测条纹光强更加一致,特别是残差较大的位置效果明显。由于相位残差引入能够提高优化精度,提出了基于载频测量技术的相位残差测量方法,用来弥补模型求解问题的不足。同时,对载频测量技术进行了原理性的介绍和误差分析,并实现了载频测量技术的相位提取算法。通过与相移算法对比,验证了载频相位算法的有效性。在验证和分析了基于干涉条纹模型的相位复原技术的基础之上,改进了光源的特征参数。即,考虑了探测器法向与光轴的夹角问题,在条纹模型中增加3个未知参数。模型改进后,给出了四种设置条件下的优化求解结果的对比分析。最后,为验证本方法最后的可靠性,通过本文提出的复原技术对两个具有代表性的实测干涉图进行相位复原,得到了较好的结果。实验表明,基于模型的单帧相位复原算法适用于低阶面形误差较大,中频误差较小的光学表面面形测量。通过本文的工作,实现了基于单帧干涉条纹模型的相位复原技术,其可以用于常用的干涉仪测量所得的干涉图相位求解,具有较强的工程应用价值。
[Abstract]:With the development of modern science and technology industry, all kinds of advanced equipment are developing in the direction of light and electrical integration. The optical system is the input or output port of these complex systems. The surface shape accuracy is the core technical index of optical elements, and whether the target can reach the standard depends on the accuracy achieved by the measurement. The key equipment of measurement. Interferometer is a modern optical element detection device which integrates light and electrical calculation. The reference surface and the laser beam returned from the surface are formed to form interference fringes and convert into digital information through the imaging system. In the acquired interference images, the information to be measured is implied. The main work of this article is to make the detector. In order to improve the adaptability of the interferometer to the environmental impact, the interferometer, such as the random phase shift technique, the dynamic interference technique, the single frame carrier stripe technique, has been developed, but these interferometers need to be from the hardware. To upgrade the interferometer equipment, for example, using multiple CCD or improving the image quality of the interferometer large field of view. In order to restore the phase of the single frame interference fringes on the basis of the existing interferometer's hardware, a phase restoration technique based on the single frame interference fringe mathematical model is proposed. The phase recovery of high precision can be achieved without the need of the hardware structure and the special requirement of the large tilt. In this way, the low cost and high precision dynamic phase interferometry can be realized. In this paper, the main principle and basic algorithm theory of the interferometer are introduced, and the filtering technique of the dry image is studied, especially the polynomial of the polynomial. The common unwrapping program and polynomial fitting program in the phase restoration algorithm are compiled, and phase restoration of phase shift phase algorithm is realized, and the effectiveness of the algorithm is verified by experiments. The mathematical model of single frame stripe and the optimization target function are built after the thorough investigation of the interferometer hardware and related algorithms. In order to optimize the model of the stripes, this paper studies the optimization principle of Newton's iterative method and genetic algorithm, analyses the solving ability of the two optimization methods to the mathematical model of the stripes, and gives the setting method of the parameter boundary in the optimization process. According to the advantages and disadvantages of the two optimization methods, the heredity is put forward. The optimization simulation results of the fringe are given in this paper. This method not only can be used for the restoration of the straight stripe phase, but also can be used for the phase restoration of the closed stripe, and the effectiveness of the optimization method is verified by simulation. On the basis of the imitation truth program, the measured two interferograms are carried out. In the actual interference fringe pattern, there is an inhomogeneous error and phase residual of the intensity distribution, but the insensitivity to this kind of error is verified by the experiment. The results of the phase solution and the phase shift method given by the fringe optimization algorithm are compared. In order to analyze the consistency between the surface shape distribution and the polynomial coefficient, in order to analyze the influence of the residual on the measurement results, the phase fitting residuals are introduced into the optimization function. The simulation analysis shows that the optimized iterative solution after the addition of the phase residual can make the optimized stripe and the measured stripe light intensity more effective, especially the larger residual position effect is obvious. Due to the introduction of phase residual to improve the optimization precision, a phase residual measurement method based on carrier frequency measurement technology is proposed to make up for the shortage of the model solving problem. At the same time, the principle of carrier frequency measurement technology is introduced and the error analysis is carried out, and the phase extraction algorithm of carrier frequency measurement technology is realized. The validity of the carrier frequency phase algorithm is verified. Based on the verification and analysis of the phase restoration technology based on the interference fringe model, the characteristic parameters of the light source are improved. That is, considering the angle problem between the detector normal and the optical axis, 3 unknown parameters are added to the fringe model. After the model is improved, the four setting conditions are given. Finally, in order to verify the final reliability of the method, two representative measured interferograms are restored by the proposed restoration technique, and the results are better. The experiment shows that the single frame phase restoration algorithm based on the model is suitable for the lower order error and the intermediate frequency error. Small optical surface profile measurement. Through the work of this paper, the phase restoration technology based on the single frame interference fringe model is realized. It can be used to solve the interferogram phase analysis obtained by the commonly used interferometer. It has strong engineering application value.
【学位授予单位】：中国科学院光电技术研究所
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TP391.41

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