Fizeau型天文光学综合孔径望远镜的若干关键技术研究
文献类型：学位论文
| 作者 | 陈欣扬 |
| 学位类别 | 博士 |
| 答辩日期 | 2007-01-26 |
| 授予单位 | 中国科学院上海天文台 |
| 授予地点 | 上海天文台 |
| 导师 | 陈欣扬 |
| 关键词 | 光学综合孔径 阵列配置 U-V平面覆盖 图像复原 维纳滤波 |
| 其他题名 | Some Key Techniques of Fizeau-type Optical Aperture Synthesis Telescope |
| 中文摘要 | Optical interferometry is a significant technique utilized to measure astronomical objects with high angle resolution. Now, Fizeau-type optical aperture synthesis telescopes(FOAST) originated from stellar interferometers with long baselines become highlight gradually. Because of common mount, multiple sub-apertures and short baselines, FOAST make it feasible for instantaneous direct imaging through focal plane combination. This paper is concentrated on three key techniques of FOAST composed of four sub-apertures: array configuration, image restoration and wavefront sensing. There are two optimal array configurations proposed instead of the symmetrical circular distribution: the asymmetrical circular distribution and the Y-type distribution. The former is analyzed according to mean square error function, and the latter lies on geometrical parameters determined by the least image restoration error criterion. The Wiener filter method is applied to image restoration in order to improve the quality of instantaneous FOAST imaging. During the design process of this filter, an approximate Power Spectral Density estimate of signal & noise from degraded images by means of local mean & variance is presented. Subsequently, a maximum expectation algorithm is also introduced into image restructuring by several images from different directions due to baselines rotation. Concerning adaptive optics of FOAT, a software simulation and an optical experiment has confirmed that it is feasible to measure wavefront errors with Pyramid Sensor(PS). Finally, a PS wavefront restructuring algorithm based on Southwell model is also designed. |
| 英文摘要 | 天文光干涉技术是当前实现高分辨率天文目标光学观测的重要技术手段之一。Fizeau型天文光学综合孔径望远镜是近年来在长基线恒星光干涉仪基础上发展起来的一种新型光干涉望远镜，具有共机架、多孔径、短基线的特点，能够通过像面干涉实现瞬时直接成像。本文即针对由4个子孔径望远镜组成的该形式望远镜开展望远镜阵列配置、图像复原与重构、波前检测与重构三项关键技术研究。 首先针对对称环布阵列开展成像质量分析，然后提出两种能够改善成像质量的阵列配置优化方案：不对称环布型和Y型。利用最小均方误差函数分析不对称环布型和Y型的MTF性能与阵列几何参数的关系；在基于最小图像复原误差评价函数基础上，比较分析对称环布和Y型阵列在图像复原方面的性能。 研究利用维纳滤波图像复原方法提高综合孔径望远镜瞬时成像质量，提出了根据局部灰度的均值、方差近似估计退化图像中的噪声、信号自相关功率谱的滤波器设计方法；针对基线旋转条件下的综合孔径成像开展基于最大数学期望的图像重构算法研究。 在四棱锥镜波前检测原理理论研究的基础上，通过软件仿真和光学实验验证该波前传感器在光学综合孔径望远镜自适应波前检测中应用可行性，并借鉴夏克-哈特曼传感器的区域法，建立了一种基于Southwell模型的四棱锥传感器波前重构算法。 |
| 语种 | 中文 |
| 公开日期 | 2011-07-01 |
| 页码 | 95 |
| 源URL | [http://119.78.226.72//handle/331011/14604]  |
| 专题 | 上海天文台_中国科学院上海天文台学位论文 |
| 推荐引用方式 GB/T 7714 | 陈欣扬. Fizeau型天文光学综合孔径望远镜的若干关键技术研究[D]. 上海天文台. 中国科学院上海天文台. 2007. |
入库方式： OAI收割
来源：上海天文台
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