大口径光学元件功率谱密度的统计法测量

针对ICF系统要求,提出了一种基于统计理论的大口径光学元件功率谱密度测量方法。该方法将大口径波前划分成足够多个子区域,分别求得每个子区域波前的功率谱密度,根据统计理论可将大口径波前功率谱密度表示为各个子区域波前功率谱密度的加权平均,其权重因子是各子区域对应的面积。模拟计算和实验结果验证了统计法测量的有效性,并表明当子区域个数大于等于8×8时,统计法测量和子孔径拼接测量得到的功率谱密度吻合较好。统计法测量对平台移动精度和环境稳定性要求不高,可应用于大口径光学元件功率谱密度的过程检测。     

高分辨力哈特曼传感器的快速波面重构和拼接

建立哈特曼传感器的模型,证明在高空间分辨力下,可以采用Hudgin模型进行波面重构,避免了采用Fried模型带来的复杂性。对哈特曼子孔径缺失破坏连续性的问题进行了分析,介绍了相应的边缘处理算法。完成了基于离散傅里叶变换的波面重构算法数值模拟,实现了波面的无损重构。针对实际应用中输入波面在被遮挡处不连续的问题,提出了基于最小二乘解的拼接方案,实现了非连续波面拼接。分析了影响波面重构速度的主要因素,提出了提高波面重构性能的方法。

     

Nighttime Image Stitching Method Based on Guided Filtering Enhancement

Image stitching refers to stitching two or more images with overlapping areas through feature points matching to generate a panoramic image, which plays an important role in geological survey, military reconnaissance, and other fields. At present, the existing image stitching technologies mostly adopt images with good lighting conditions, but the lack of feature points in scenes with weak light such as morning or night will affect the image stitching effect, making it difficult to meet the needs of practical applications. When there exist concentrated areas of brightness such as lights and large dark areas in the nighttime image, it will further cause the loss of image details making the feature point matching unavailable. The obtained perspective transformation matrix cannot reflect the mapping relationship of the entire image, resulting in poor splicing effect, and it is difficult to meet the actual application requirements. Therefore, an adaptive image enhancement algorithm is proposed based on guided filtering to preprocess the nighttime image, and use the enhanced image for feature registration. The experimental results show that the image obtained by preprocessing the nighttime image with the proposed enhancement algorithm has better detail performance and color restoration, and greatly improves the image quality. By performing feature registration on the enhanced image, the number of matching logarithms of the image increases, so as to achieve high accuracy for images stitching.     

子孔径拼接干涉检测及其精度分析

介绍了利用小口径干涉仪检测大口径光学元件的方法，从统计的角度出发，详细地推导了子孔径拼接干涉检测技术中拼接参量的具体求解过程，以及使用统计回归方法分析了拼接检测系统精度。并通过实验对该理论进行了实际分析运算。     

Locally rigorous electromagnetic analysis of non-periodic gratings with large size and small features in the non-scalar validity domain by the field stitching method

Scalar theory is a simple and rapid method to analyse and conceive diffractive optical element and gratings, in some limited cases. When we want to deflect wave fronts with large angles (for telecommunication devices, for instance) or when the features of the grating are around the order of the wavelength, scalar optics fail to be accurate, then adapted rigorous electromagnetic tools must be used. To correct the increasing cost in memory saving and time consuming with the size of the grating, we present here an original `field stitching' method adapted for aperiodic gratings (FSA). This method, initially developed for periodic gratings is extended here to analyse locally and rigorously aperiodic gratings with large sizes and small features without having some of the above-mentioned inconvenients.     

使用子孔径拼接法检测大口径光学元件

为了解决大口径光学元件检测过程中成本高、空间分辨率低这两个主要难点 ,提出了使用小口径、高精度干涉仪分次检测大口径元件 ,然后通过优化算法将检测结果进行拼接处理 ,最终得到原大口径元件波前信息的方法 ,并作了初步的拼接模拟实验 ,确认了这一方案的可行性。     

基于子孔径拼接的Hindle球检测法

为了能够准确获取基于子孔径拼接的Hindle球检测大口径双曲面镜的Hindle球参数,研究了Hindle球检测凸双曲面镜的理论模型,并从几何光学入手,讨论了基于子孔径拼接的Hindle球检测法的系统结构,推导了符合子孔径拼接要求的小口径Hindle球的参数计算式。对一个凸双曲面镜进行了在不同测量环带数目下的基于子孔径拼接的Hindle球检测法和经典Hindle球检测法的Hindle球参数对比。结果表明该Hindle球检测方法使Hindle球参数更合理。     

样本容量对子孔径拼接检测精度影响的分析

应用数理统计理论及线性回归分析方法，详细分析了在子孔径拼接检测中样本容量对测量精度的影响。通过计算，确定了当子孔径拼接干涉检测中样本容量大于104时，既可保证检测精度，又能减小计算的复杂程度。     

子孔径拼接干涉检测实验研究

为了满足国内ICF系统大口径光学元件的检测需要,提出了子孔径拼接干涉检测的方法。该方法是利用小口径干涉仪对大口径光学元件进行高精度波前检测。建立了拼接检测计算的模型。利用最小二乘法计算得到拼接参数,从而恢复大口径光学元件的全孔径波前相位分布。在理论分析的基础上设计了一套检测装置,对该装置的稳定性进行了实验研究。进行了两口径拼接检测的实验。拼接结果与全孔径检测结果进行了比较。结果表明,该检测方案能够满足大口径光学元件的检测要求。     

大口径镜面的多孔径拼接技术

提出了完成大口径镜面的多孔径拼接技术，即利用实时相位探测技术实现尺寸小，精度高的子孔径镜面之间的位相合成，从而获得性能优越的大口径镜面，然后对多孔径拼接技术原理进行了较为详细的数学描述，并完成了原理性实验，最后获得了实验结果。