近景摄影测量在LAMOST光纤位置检测中的应用研究

发布时间：2018-03-18 17:41

本文选题：近景摄影测量　切入点：线阵CCD　出处：《中国科学技术大学》2010年博士论文　论文类型：学位论文

【摘要】： “大天区面积多目标光纤光谱望远镜(Large Sky Area Mulit-object Fiber Spectroscopic Telescope, LAMOST)"是我国的一项重大科学工程项目,在其直径1.75米的焦面板上,布置有4000根光纤。LAMOST观测时,望远镜光学系统使天体目标成像在焦面上,然后光纤定位系统控制4000根光纤与这些天体的像对准而获取它们的光谱。由于存在控制、机械加工、安装、工作环境改变等引起的误差,如果光纤定位系统是开环控制,精度不易保证,因此为了修正这些误差,使LAMOST能够准确运转,必须要对光纤在焦面上的位置进行精密检测。 LAMOST光纤位置检测有如下要求：大视场、多离散目标、高精度、快速、非接触,几乎囊括了所有的高检测标准。在常规的位置测量方法中,近景摄影测量最有可能全部符合这些要求,因此本文对近景摄影测量在光纤位置检测中的应用进行了详细研究。摄影测量有基于线阵CCD和面阵CCD的两种可选设备,针对各自优缺点,本文提出了多线阵CCD的扫描检测方案和面阵CCD像机的分区检测方案,并对这两种方案都从原理和方法上进行了细致的探讨。论文的主要内容包括： 1.设计并研制了一套由3个线阵CCD组成的光纤位置试验检测系统,该系统检测静止光纤坐标的误差为±0.9μm(2σ),具有很好的稳定性。 2.实现了线阵CCD试验检测系统对动态光纤的位置测量。对线阵CCD姿态标定、转换拼接和参数优化后,实验显示,该系统检测光纤之间距离的误差只有±5μm(2σ),具有较高的精度。但高检测精度需要复杂的标定和优化,该过程需要大范围高密度的标定光纤。 3.建立了光斑定位算法(光重心法)的误差分析模型,结合实验研究,提出了一个最佳的检测条件,在该条件下,光重心法的精度达到0.04像素,并以光重心法的精度为依据确立检测子区域的大小。 4.提出一种改进的光束法平差自标定方法,实现面阵CCD像机的在线高精度标定。实验结果显示,该标定方法只需要数量很少的控制点就能够获得与多控制点的传统标定方法相当的精度。本文对线阵CCD方案的研究结果是,该方案具有较高的理论检测精度,若要在LAMOST现场应用,不仅需要大范围高密度的标定光纤,而且对系统硬件的性能和精度都有很高要求,以目前技术手段难以实现。本文研究并解决了面阵CCD方案中的几个关键问题,保证了面阵CCD方案从实验室论证顺利移植到LAMOST现场应用。
[Abstract]:Large Sky Area Mulit-object Fiber Spectroscopic Telescopes (LAMOST) is an important scientific engineering project in China. The telescope's optical system imagines celestial objects on the focal plane, and then the optical fiber positioning system controls 4,000 optical fibers to align with the images of these objects to obtain their spectra. If the optical fiber positioning system is open-loop control, the precision is not easy to guarantee, so in order to correct these errors and make LAMOST work accurately, it is necessary to accurately detect the position of optical fiber on the focal plane. LAMOST fiber position detection has the following requirements: large field of view, multiple discrete targets, high accuracy, fast, non-contact, almost all high detection standards. Close-range photogrammetry is most likely to meet these requirements, so the application of close-range photogrammetry in optical fiber position detection is studied in detail in this paper. There are two kinds of optional equipments for photogrammetry based on linear CCD and plane array CCD. In view of their respective advantages and disadvantages, this paper puts forward the scanning detection scheme of multi-linear CCD and the area detection scheme of area array CCD camera. The principle and method of the two schemes are discussed in detail. The main contents of the thesis include:. 1. An optical fiber position testing system composed of three linear CCD is designed and developed. The error of measuring static fiber coordinates is 卤0.9 渭 m ~ 2 蟽 ~ (-1), which has good stability. 2. The position measurement of dynamic optical fiber by linear CCD test system is realized. After calibrating the attitude of linear array CCD, converting splicing and optimizing parameters, the experimental results show that, The error of measuring the distance between optical fibers is only 卤5 渭 m ~ 2 蟽 ~ (-1), which has a high precision, but the high detection precision needs complex calibration and optimization, and the process requires a large range and high density of calibrated fiber. 3. The error analysis model of spot location algorithm (light center of gravity method) is established, and an optimal detection condition is put forward based on the experimental research. Under this condition, the accuracy of the optical center of gravity method reaches 0.04 pixels. Based on the accuracy of the light center of gravity method, the size of the detection sub-region is established. 4. An improved self-calibration method of beam adjustment is proposed to realize the on-line high-precision calibration of CCD camera. The experimental results show that, The calibration method requires only a small number of control points to achieve a precision comparable to the traditional calibration method for multiple control points. The research results of the linear CCD scheme in this paper show that the scheme has high theoretical detection accuracy. In order to be applied in LAMOST field, it not only needs a wide range of high-density calibrated optical fibers, but also requires high performance and precision of the system hardware. It is difficult to achieve with the present technical means. In this paper, several key problems in the area array CCD scheme are studied and solved to ensure the smooth transplantation of the plane array CCD scheme from the laboratory demonstration to the LAMOST field application.
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2010
【分类号】：TH751

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