| 题名 | 高分辨率成像系统波像差检测中的图像处理技术研究; 高分辨率成像系统波像差检测中的图像处理技术研究 |
| 作者 | 1刘景峰,电工研究所 |
| 学位类别 | 博士 |
| 答辩日期 | 2008-06-10 |
| 授予单位 | 中国科学院电工研究所 |
| 导师 | 1李艳秋,电工研究所 |
| 关键词 | 波像差 相移点衍射干涉仪 Schwarzschild投影物镜 傅立叶变换 干涉图 相位展开 wavefront aberration phase-shifting point diffraction interferometer(PS/PDI) Schwarzschild project optics Fourier-Transform interferogram phase unwrapping |
| 其他题名 | 高分辨率成像系统波像差检测中的图像处理技术研究 |
| 中文摘要 | 光学干涉测量是以光波长为计量单位的一种高精度、高灵敏度、非接触性的光学测试技术，能实现实时、快速、高精度、多参数、全场、动态测量,在生产和科学研究中有着广泛的应用。随着光学系统的分辨率越来越高，为了达到衍射极限分辨率，对光学元件和光学系统提出了更高的要求。与传统的点衍射干涉仪相比，相移点衍射干涉仪采用针孔衍射的球面波作为参考波，通过移动光栅同时引入了相移，可以应用在极紫外线，X射线等短波段在线检测包括设计残差、装调误差和面形误差在内的整个成像系统的总的波像差。这对于指导高分辨率成像光学系统的装调，提高光学加工水平，提高系统的分辨率更具指导意义。本文对高分辨率成像系统波像差检测中的关键技术——干涉图数据处理技术进行了深入的研究，包括干涉图的去噪、相位提取、相位展开、波面拟合等。其主要研究内容包括： 干涉图的处理是光学干涉测量的关键技术，它决定了测量结果的可靠性和精确性，迄今已有一系列有效的位相测量方法。本文首先对位相测量方法作了详细概述，在此基础上对傅立叶变换处理单幅干涉图做了详细研究和改进。重点解决了采用二维离散傅立叶变换(DFT)处理干涉图求解相位过程中的三个问题：首先从理论上分析了采用傅立叶变换处理干涉图中的频谱泄漏产生的原因以及改善频谱泄漏的方法；接着重点讨论了圆形干涉的区域外插问题，结合图像修复，提出了一种基于样本块的干涉图外插算法。算法利用干涉图的可信度和等照度线特征，来确定填充块的优先权，然后在干涉图的已知区域寻求与待填充块最相似的样本块进行填充，计算机模拟和试验证明能够获得好的外插效果；最后讨论了滤波器的中心频率的确定与滤波带宽的选取原则与方法。 二维相位展开是光学干涉测量数据处理的关键技术之一，加权最小二乘法是目前研究较多的一种相位展开方法，本文在此基础上针对含噪声包裹相位图进行相位展开的问题，建立了基于预条件共轭斜量法的加权最小二乘相位展开算法模型，引入非加权二维离散余弦变换求解具有纽曼边界条件的泊松方程得到的解作为预条件，从而加快迭代速度。算法中的权重项由新质量图确定，得到最小二乘意义下的展开相位。模拟与试验表明，算法能有效处理含噪声的包裹相位图，得到较好的相位展开结果。 参与研制了一套用于检测其系统波像差的相移点衍射干涉仪的原理样机和接近衍射极限分辨率的Schwarzschild微缩投影物镜系统，利用该干涉仪和本论文研究的图像处理技术检测632.8nm可见光波段Schwarzschild微缩投影物镜系统的总波像差（包括设计残差、加工和装调误差）。测量结果表明，系统波像差为0.1293波长，重复性为0.0040波长。 Optical interferometry, with the ability of noncontact, whole field measurement, high sensitivity and high accuracy, can realize real time, high speed, precision, multi-parameters, whole field, dynamic measurement and continues to be a major tool in the fields of inspection, testing, and measurement not only for the optical industry but for an extremely wide variety of industrial and scientific purpose. In order to achieve diffraction-limited resolution and the required image quality, higer requirements are set to the optics components and optics system. The design of Phase-shifting point diffraction interferometer (PS/PDI) overcomes several of the limitations of the conventional point diffraction interferometer (PDI), Translating the grating beamsplitter introduces a controllable relative phase-shift between the test and reference wavefronts. Phase-shifting point diffraction interferometer (PS/PDI) can be applied in the imaging system’s overall wavefront aberration online measurement, the experiments light sources can be extremely ultraviolet ray, X beam and so on other short-wave.The overall wavefront aberration include the design, figure, alignment error. This measurement way is more significative to direct the high resolution imaging system’s alignment, improve the processing level and enhance the imaging system resolution. The in-depth researches on the interferogram analysis of wavefront metrology for high resolution imaging system are carried out in this dissertation.It includes noise removal, phase measurement, phase unwrapping, and wavefront sufface fitting. The main work of the dissertation is as follows: Interferogram analysis is one of the key technologies that enable optical for wavefront error measurement. In many case the measurement parameters have direct relations with optical phase distribution. a lot of phase measurement methods have already existed. First of all a review is given, based on it, phase retrieval algortithm with single interferogram using two-dimensional discrete Fourier-Transform is detail discussed and some improvements are achieved. Three main problems which existed in the phase retrieval process are resolved. First of all, phase errors caused by leakage in interferogram analysis using discrete Fourier-Transform is discussed theoretically. and a fringe extrapolation method is proposed to decrease these errors and improve measurement precision. Secondly extrapolating a circular interferogram to square interferogram is discussed. In this thesis, a method of exemplar-based image inpainting is proposed. By analyzing of the confidence and isophote of interferogram, the priority of each patch on the “fill front” is calculated. After the best patch is found in the source region of the interferogram, the value of each pixel in the patch on the fill front is copied from its corresponding position in the best patch. Computer simulation and experiment make it clear that the proposed algorithm extrapolate the texture and structure information effectually. Finally how to select a optimum bandpass filter is discussed. Two-dimensional phase unwrapping is widely applied in a variety of fields including optical interferometry, adaptive optics, synthetic-aperture radar and image processing. In order to process the wrapped phase with noise, we apply preconditioner conjugate gradient method (PCG) to solve the weighted least-squares phase unwrapping problem. In this thesis, the preconditioner is obtained by solving an unweighted least-square phase unwrapping problem. The discrete Poisson equation is solved by means of discrete cosine transform (DCT). This algorithm converges much faster than the Picard algorithm. A new quality map is adopted to determine the weights. Computer simulation and experimental examples make it clear that the preconditioner conjugate method works successfully when noise exists in wrapped phase images. Combining the research project, in order to conduct a proof of concept and to gain experience in the operation, we have a new wavefront metrology project, the objective of the project is to develop a wavefront metrology system which can test system overall wavefront aberration including design, alignment and figure error. We have built a phase-shifting point diffraction interferometer prototype to test Schwarzschild optics which consists of two spherical mirrors. Preliminary testing using visible radition has been performed, at the same time, the interferograms can be successfully processed by our softeare which is compiled based on the above algorithms. The results show that the Schwarzschild optics wavefront error is 0.1293 wavelength and the measurement repeatability is 0.0040 wavelength , more experiments and analysis are now in progress. |
| 语种 | 中文 |
| 公开日期 | 2010-10-18 |
| 页码 | 133 |
| 分类号 | TM1 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.iee.ac.cn/handle/311042/6750]  |
| 专题 | 电工研究所_其他部门_其他部门_博士学位论文 |
| 推荐引用方式 GB/T 7714 | 1刘景峰,电工研究所. 高分辨率成像系统波像差检测中的图像处理技术研究, 高分辨率成像系统波像差检测中的图像处理技术研究[D]. 中国科学院电工研究所. 2008. |
| 个性服务 |
| 查看访问统计 |
| 相关权益政策 |
| 暂无数据 |
| 收藏/分享 |
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。
修改评论