分离式靶标摄影测量在LAMOST中的应用  

Application of Photogrammetry with Separate Targets to the LAMOST

作　　者：李明[1] 王钢[2] 

机构地区：[1]贵州大学理学院,贵州贵阳550025 [2]中国科学院光学天文重点实验室(国家天文台),北京100012

出　　处：《天文研究与技术》2011年第3期315-322,共8页Astronomical Research & Technology

摘　　要：为了获取LAMOST焦面板上光纤的零位位置,提出了一种基于分离式标准靶标的高精度摄影测量方法。首先,根据Tsai摄像机标定参数模型介绍了CCD相机的标定原理。然后介绍了用光重心算法求取靶标发光点像面坐标及通过球面三角公式计算靶标发光点物面坐标。接着,利用最小二乘法导出了含标定参数的方程组。最后,介绍了标准靶标的放置方法以及提高光纤位置测量精度的靶标取法。实验结果表明:CCD相机的标定残差平均值为8.8μm;标定残差的标准差为5.3μm。测量方法简单易行,通过仔细分析,找出了残差偏大的原因,对后续进一步测量实验有重要指导意义。In order to obtain optical-fiber zero-point positions in the focal panel of the LAMOST,we present a method of high-precision photogrammetry based on separate calibration targets.First,according to the Tsai camera calibration model,we describe the principle of CCD-camera calibration,which is essentially a mapping from the coordinates of targets in image surface to the coordinates in object plane.We then describe the calculation methods of the coordinates in the image surface and object plane,using a centroid algorithm and the spherical trigonometry.Equations with calibration parameters are subsequently derived by the least-squares fitting.We finally show the proper positioning of the calibration targets,and analyze the effective setting of targets to improve measurement accuracy of the optical-fiber positioning.Our experimental results indicate that the average value of residual CCD-camera calibration errors is 8.8 μm and the standard deviation is 5.3 μm.The measurement method is reliable and easy to be carried out.With a careful theoretical analysis the paper lists the reasons of why the residual errors are large in certain sense.This research will serve as a guidance to further measurement experiments.

关 键 词：光学测量 LAMOST 分离式靶标摄影测量 球面三角 CCD相机标定 光纤位置 

分 类 号：P111.21[天文地球—天文学]