摘要
宇宙线事件是CCD和CMOS空间探测图像中普遍存在的现象,对目标的识别和提取造成了干扰。对于空间天文观测图像,提出了一种基于天文位置定标的识别算法,并在230帧嫦娥三号月基光学望远镜的CCD图像中,共检测到29731例宇宙线事件。与传统的拉普拉斯算法相比,本算法检测到的宇宙线事件总数多11.14%,多出的部分主要是形态与星像类似的宇宙线事件;在拉普拉斯算法检测到的样本中,98.07%可被本算法检测到;对本算法没有检测到的1.93%样本进行了检查,发现其中48.64%为恒星星像,是错误识别。分析统计了宇宙线事件在月基光学望远镜CCD靶面上的电子沉积分布,和哈勃太空望远镜的两个CCD探测器的结果对比,发现两者形态类似,但前者的峰值略高;进一步分析了宇宙线事件入射角度在CCD靶面上的二维分布,发现在两个方向上有明显超出,可以理解为探测器在嫦娥三号着陆器内部等效铝厚度较小。最后,本文提取出所有识别出的宇宙线事件的形态,建立了“CCD探测器宇宙线实体样本库”,可为空间天文望远镜图像仿真系统提供依据。
Cosmic rays interfere with target recognition and extraction and this is a common phenomenon detected in charge-coupled device(CCD)and complimentary metal-oxide semiconductor images taken in space.In this study,we proposed a recognition algorithm based on stellar astrometry for space astronomical images,enabling us to extract a total of 29731 cosmic-ray events in the 230 CCD images taken by the Chang'e-3 Lunar-based Ultraviolet telescope(LUT).On the one hand,this number was 11.14% more than the one detected by traditional Laplace algorithm,which was primarily because of events detected with a shape similar to a star.On the other hand,our algorithm failed for only 1.93% of the cases detected by the Laplace algorithm.Among these failed cases,48.64% were stars,indicating misidentification by the Laplace algorithm.In addition,although peaks appeared at a higher value,the distribution of the electron deposition on the LUT CCD was comparable with those reported for the two Hubble Space Telescope CCDs.With a two-dimensional distribution of the incident angle of cosmic rays on the CCD surface,we identified significant excesses in two directions,which could be understood by a smaller equivalent aluminum thickness of the Chang'e-3 lander.Finally,we built a public library of cosmic rays recorded by the LUT CCD by extracting the patterns of all the detected cosmic rays,which might be useful for future space telescope image simulation systems.
作者
刘奇
王竞
黄茂海
魏建彦
LIU Qi;WANG Jing;HUANG Mao-hai;WEI Jian-yan(Key Laboratory of Space Astronomy and Technology,National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China;University of Chinese Academy of Sciences,Beijing 100049,China;Guangxi Key Laboratory for Relativistic Astrophysics,School of Physical Science and Technology,Guangxi University,Nanning 530004,China)
出处
《光学精密工程》
EI
CAS
CSCD
北大核心
2021年第10期2330-2339,共10页
Optics and Precision Engineering
基金
国家重点研发计划资助项目(No.2020YFE0202100)
中国科学院战略性先导科技专项,空间科学基金资助项目(No.XDA15052600,No.XDA15016500)。
关键词
月基光学望远镜
电荷耦合器件
宇宙线
天文位置定标
天光背景拟合
lunar-based ultraviolet telescope
charge coupled device
cosmic rays
astrometry
sky light background fitting
