图象重建中规定直方图约束与最大熵方法的比较

图象重建中规定直方图约束与最大熵方法的比较 AN EXPERIMENTAL COMPARISON OF SPECIFIED HISROGRAM CONSTRAINT AND ME IN IMAGE RECONSTRUCTION 王延平 Wang Yanping 1 2 3 first-author 钟志刚 Zhong Zhigang 1 2 3 梅雁诚 Mei Yancheng 1 2 3 武汉大学空间物理与电子信息学系 武汉大学空间物理与电子信息学系 Department of Space Physics and Electronic Information,Wuhan University Department of Space Physics and Electronic Information,Wuhan University 武汉大学空间物理与电子信息学系,武汉 武汉大学空间物理与电子信息学系,武汉 ,430072 ,430072 本文比较详细地给出了规定直方图约束与最大熵方法在不完全投影数据重建中的实验结果,并进行了比较。从中可以看出,在丢失一定投影信息的情况下,不论是视角受限型,还是中空型、截断型不完全投影数据重建,规定直方图约束在重建图象的质量、收敛特性以及抗干扰能力等方面,要比最大熵方法具有较大的优越性。 Image reconstruction from incomplete projection data is a very vivid topic in recent years. As in many practical cases, it is impossible to get all the information needed for the reconstruction. And consequently, we are forced to use not only the available projection data, but also some prior information or knowledge in order to reconstruct an acceptable image. Becasue many inverse problems do not have unique solution, the incorporation of constraints is often necessary to reduce the number of possible solutions. With a number of iterative procedurs,this is conveniently done. Prior information plays an important role in the process of reconstruction. There are several kinds of prior information constraints. Among them, maximum entropy method （ME） and specified histogram constraint（SHC） are two good algorithms for image reconstruction from incomplete projections. In the first part of this paper, we introduce general concepts of ME and SHC, emphasizing on the algorithm of SHC. And then,for several Wpical cases,we compare them experimentally. In each case, the images obtained by ME and by SHC（after 5times of iteration）are presented. They are compared and analysed quantitatively. The results obtained by SHC are much better than that by ME in many aspects,such as convergence,image quality and stability etc. 图象重建 层析分析 规定直方图约束 最大熵 image reconstrution tomography specified histogram constraint （SHC） maximum entropy（ME） TN941.1 1993-03-01 2021-04-01 3