同步辐射双能CT图像的高精度配准研究  

Research on High Accuracy Registration of Dual Energy CT Images in Synchrotron Radiation

作　　者：李巧[1,2] 周光照[1] 肖体乔[1] 

机构地区：[1]中国科学院上海应用物理研究所,上海201800 [2]中国科学院大学,北京100049

出　　处：《光学学报》2016年第4期108-115,共8页Acta Optica Sinica

基　　金：国家自然科学基金重点项目(81430087);国家自然科学基金联合重点项目(U1232205);国家973计划(2010CB834301);CAS-CSIRO国际合作项目(GJHZ1303)

摘　　要：对双能计算机断层扫描(CT)图像进行三维图像配准是准确获取样品内部元素分布信息的前提。针对同步辐射双能CT成像存在的图像空间失准问题,提出了一种以互信息作为衡量双能CT图像相似度的图像配准方法。采用部分体积(PV)插值算法计算互信息,采用遗传算法进行较优参数的搜索,并以该参数作为Powell算法搜索的起始点,结合基于Hanning窗的部分体积插值(HPV)算法搜索得到最佳配准参数。数值模拟验证了HPV算法的优越性,同时配准精度达到亚像素级。实验结果表明,该方法能够有效配准双能CT图像并获得三维元素分布信息。Image registration is the premise for extracting accurate inner element distribution information of samples from dual-energy computed tomographic （CT） images. In order to solve the misalignment of dual- energy CT images in synchrotron radiation, an image registration method is proposed which uses mutual information as the standard to measure similarity of two dual-energy CT images. The partial volume （PV） interpolation algorithm is used to calculate mutual information and the genetic algorithm is used to search the initial good parameters. Then the original searching point for Powell algorithm is initialized with these parameters and the PV interpolation based on Hanning window （HPV） is combined to search the optimal registration parameters. The numerical simulation testifies the advantages of HPV algorithm and the accuracy of registration achieves subpixel. Experimental results show that the proposed method is effective for dual- energy CT image registration and acquirement of three-dimensional distribution of elements.

关 键 词：成像系统 双能计算机断层扫描 同步辐射 遗传算法 POWELL算法 HPV算法 

分 类 号：TP751.1[自动化与计算机技术—检测技术与自动化装置]