基于大视场反卷积的天文图像叠加方法  

Astronomical Image Co-adding Method Based on Wide Field Image Deconvolution

作　　者：蔡博君 贾鹏 孙荣煜[3] 王伟男 CAI Bo-jun;JIA Peng;SUN Rong-yu;WANG Wei-nan(College of Physics and Optoelectronics,Taiyuan University of Technology,Taiyuan 030024;Purple Mountain Observatory,Chinese Academy of Sciences,Nanjing 210008)

机构地区：[1]太原理工大学物理与光电工程学院,太原030024 [2]Department of Physics Durham University [3]中国科学院紫金山天文台,南京210008

出　　处：《天文学报》2019年第1期40-54,共15页Acta Astronomica Sinica

基　　金：国家自然科学基金项目(11503018;U1631133);山西省高等学校科技创新项目(2016033)

摘　　要：地基望远镜在成像过程中,由于受大气湍流、望远镜静态像差、跟踪误差、指向误差及视场变化的影响,不同视场区域的PSF (Point Spread Function)具有差异;同时,不同望远镜获取的图像PSF也存在差异.将多个望远镜获取的星象直接叠加至相同的区域后,图像质量受像质最差的望远镜限制,最终观测分辨率和灵敏度均会受到影响.通过图像复原,可以提高图像质量,进而提高叠加效果.根据该思路提出了1种基于PSF分区的迭代图像复原方法:该方法首先通过SOM (Self-organizing Maps)对PSF进行聚类分析,利用同类别PSF的平均PSF进行反卷积,再将反卷积结果按PSF聚类结果分割为不同大小的子图,最后将子图进行拼接.图像复原在提高图像质量的同时,降低了PSF不一致性对图像叠加带来的影响.将几个望远镜在同一时刻获取的图像经反卷积处理之后利用图像配准算法进行矫正并叠加,可获得高信噪比图像.对实际望远镜获取的数据处理后的结果表明:图像在进行复原和叠加过程中,星象目标信噪比不断提升,提高了成像系统对暗星的探测能力.Due to atmospheric turbulence,telescope static aberrations,tracking and pointing errors,the point spread functions(PSFs)in different field of views are different.Meanwhile,there are different PSFs in the images obtained by different telescopes.The quality of co-adding image is limited by the image with the poorest quality,and the resolution and sensitivity of the quad-channel telescope will also be affected.Dividing the image into some regions with the same type of PSF and deconvolving these regions can improve the quality of the co-adding images.According to this theory,an image restoration algorithm based on the image clustering is proposed.Firstly,the PSFs are clustered by Self-Organizing Maps,and the mean PSF of the same category is used to deconvolve images with the same type of PSF.Then through the image registration,the image with a high signal to noise ratio can be obtained.The result shows that the signal to noise ratio of the astronomical images are improved with our method,and the detection ability of faint stars is improved.

关 键 词：天文技术:图像处理 望远镜 大气效应 

分 类 号：P111[天文地球—天文学]