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太阳高分辨高速重建算法的研究
其他题名Research on High Speed High Resolution Solar Image Reconstruction Algorithm
向永源
学位类型博士
导师刘忠
2016-07-01
学位授予单位中国科学院大学
学位授予地点北京
培养单位中国科学院云南天文台
学位专业天文技术与方法
关键词新真空太阳望远镜 太阳图像重建 斑点成像 多通道观测 并行计算
摘要深入研究太阳大气活动现象需要大视场、长时间和多波段的高时空分辨率数据。目前地基大口径太阳望远镜都借助于自适应光学技术和高分辨图像重建技术实现太阳高空间分辨率成像观测。高分辨图像重建技术能有效克服湍流影响而实现目标接近接近望远镜衍射极限分辨率成像,相比自适应光学技术,它容易操作和实现,但也因重建算法运算耗时、重建流程繁琐复杂而缺乏实时性。随着一米新真空太阳望远镜NVST在2010年建成和投入使用,国内太阳观测迈入高空间分辨率时代。目前NVST采用斑点重构方法来处理每日观测数据。为能及时快速的处理海量观测数据,需有一套高效的重建策略和高速运算的重建算法。本论文结合NVST实际观测,开展太阳高分辨高速重建算法的研究,研究内容包含NVST数据重建模式、重建算法优化以及算法并行运算等几个方面。具体的研究细节和取得的相应进展如下:根据NVST实际观测和数据处理现状,确立了两级数据处理模式Level1和Level1+,在斑点重构算法比较耗时的大背景下,两级处理模式让NVST做到了数据及时发布。此外,在保证数据处理精度的前提下,对位移叠加法和斑点掩模法进行了深入分析和优化,对其中关键参数进行了实验分析,最大限度地精简了运算量,提高了观测数据重建效率。在算法优化的基础上,采用硬件加速方式提高了高分辨重建算法的运算速度。论述了高分辨重建算法中能够并行计算的环节,就高分辨重建算法在GPU和集群中并行加速进行了实验,在GPU中实现了准实时的Level1 级重建并实现了子块图像四维重谱并行计算;另外在集群中也实现了Level1 和Level1+级快速重建。对NVST多通道数据的实际处理展开Level1和Level1+处理方法的应用研究,并针对实际观测和数据重建中遇到的问题给出解决方案。提出了一种重建中抑制光球通道sCMOS相机固定图形噪声的方法,通过对月亮Level1+级重建的结果看出,“二次平场”能有效抑制斑点掩模法中的固定图像噪声放大。在日面边缘目标的重建实验中,提出了一种改进的互相关方法,该方法有效避免了相关极值误差,保障了边缘目标高分辨重建的顺利进行。为提高色球数据重建结果的信噪比,采用并改进了Level1重建算法,在改进方法后,重建结果的分辨率大幅提高。
其他摘要In depth studying the phenomenon of solar atmospheric activity requires large field of view, long time and multi band high spatial and temporal resolution data. At present, almost all large aperture solar telescopes are based on adaptive optics technique and high resolution image reconstruction technique to realize the high spatial resolution observation of the sun. High resolution image reconstruction can effectively overcome the influence of atmospheric turbulence and make solar telescope achieve near diffraction limit resolution imaging. Compared with the adaptive optics technique, it is easy to operate and realize, but also lack of real time that because of the computing is time-consuming and reconstruction process are cumbersome and complex.With one meter New Vacuum Solar Telescope NVST was successfully completed and put into use in 2010, the domestic solar observations goes into the era of high spatial resolution. NVST is currently using speckle reconstruction method to deal with daily observation data. In order to deal with massive data in a timely and rapid manner, we must have an efficient data processing strategy and high speed reconstruction algorithm. In this thesis, based on the NVST actual observation, we study on the high speed high resolution solar images reconstruction algorithm. The research contents include the NVST data reconstruction model, the optimization of the reconstruction algorithm and the parallel operation of the algorithm. Details of the study and the corresponding progress achieved are as follows:According to the actual observation and data processing status, we establish data processing mode Level1 and Level1+. The two level processing mode allows NVST to release data in a timely manner in the case of speckle reconstruction algorithm is time consuming. Under the precondition of ensuring the accuracy of data processing, we analyze and optimize the shift-and-add method and the speckle masking method. We analysis the key reconstruction parameters through experiments, and simplify the computation as much as possible to improve the efficiency of data reconstruction.On the basis of the optimization of the algorithm, we use hardware to improve the speed of the high resolution reconstruction. We discuss the part of the high resolution reconstruction algorithm that can be executed in parallel computing, and perform experiments of high resolution reconstruction algorithm accelerating in the GPU and cluster. We realize the real-time reconstruction of class Level1 in GPU, and realize the parallel computation of sub block image four-dimensional bispectrum. In addition, we also achieve rapid reconstruction of Level1 and Level1+ in cluster.Application of Level1 and Level1+ to the practical processing of NVST multi-channel data is studied, and solution to the problems encountered in the actual observation and data handling is given. We propose a method to eliminate the influence of the fixed image noise generated by the sCMOS. According to the results of the Level1+ reconstruction of the moon, it is seen that the “second flat-fielding” can effectively suppress the fixed noise amplification in the speckle masking reconstruction. An improved cross correlation method is proposed for the reconstruction of the solar limb. This method can effectively avoid the correlation error, and guarantee the smooth progress of the reconstruction of solar limb activity. To improve the signal to noise ratio of the chromosphere data, we adopt and improve the Level1 reconstruction algorithm. The resolution of the reconstructed result is greatly improved.
学科领域天文学 ; 太阳与太阳系 ; 太阳与太阳系其他学科 ; 计算机科学技术 ; 计算机应用 ; 计算机图象处理
学科门类理学 ; 理学::天文学 ; 工学 ; 工学::计算机科学与技术(可授工学、理学学位)
页数103
语种中文
文献类型学位论文
条目标识符http://ir.ynao.ac.cn/handle/114a53/25367
专题抚仙湖太阳观测和研究基地
作者单位中国科学院云南天文台
第一作者单位中国科学院云南天文台
推荐引用方式
GB/T 7714
向永源. 太阳高分辨高速重建算法的研究[D]. 北京. 中国科学院大学,2016.
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