多种图像采集策略下X射线折射信息的提取研究  

Simulation of X-ray refraction information extraction using multiple image-collecting strategies

作　　者：王云波[1] 李公平[1] 潘小东[1] 许楠楠[1] 

机构地区：[1]兰州大学核科学与技术学院,兰州730000

出　　处：《物理学报》2014年第10期150-161,共12页Acta Physica Sinica

基　　金：中央高等学校基本科研基金(批准号:860452)资助的课题~~

摘　　要：不同的图像采集策略下,基于分析晶体相衬成像技术的折射信息提取方法(衍射增强成像法、广义衍射增强成像法、多图成像法)的折射角提取结果有明显的差异.与摇摆曲线腰位作为图像采集位置的传统策略相比,采集位置靠近摇摆曲线中轴时,衍射增强成像法能够提取得到更好的折射角结果.广义衍射增强成像法的三个图像采集位置相对摇摆曲线中轴对称时,折射角的提取结果好于采集位置非对称的结果,并且采集位置靠近摇摆曲线中轴时,折射角的提取结果好于摇摆曲线腰位或趾位的结果.对于多图成像法,相邻图像采集位置的角度间隔大于摇摆曲线半高全宽时,折射角提取结果非常差;而当角度间隔小于半高全宽并且图像采集位置对应的角度范围接近样品的最大折射角理论值时,能够获得很好的折射角提取结果.此研究有助于实验上对图像采集策略的合理选择以及对折射信息提取方法的更深理解.With different strategies collecting images, the extraction results of refraction information using the diffraction- enhanced imaging （DEI）, generalized diffraction-enhanced imaging （G-DEI） or multiple-image radiography （MIR） algorithm of analyzer-based imaging technique are greatly different from each other. Compared with the conventional strategy in which the images are acquired at the waist positions of rocking curve （RC）, the one with the positions closer to the central axis of RC can obtain more accurate refraction information for the DEI algorithm. For the G-DEI algorithm taking three images, if the positions, where images are obtained, are symmetrical with respect to the central axis of RC, the extraction result of refraction information is better when the positions are asymmetrical. Besides, by comparison with the strategy in which the images are acquired at the waist or toe positions, the one with the positions closer to central axis of RC can obtain better result. If the angle interval of neighbor positions is larger than the full-width at half-maximum （FWHM） of RC, the extraction result of the MIR algorithm is bad. When the angle interval is smaller than the FWHM, and the value of angle range of all positions collecting images is close to the maximum theoretical value of sample, the extraction result is very good. This study will be helpful for reasonably choosing the image-collecting strategies in experiment, and further understanding the extraction algorithms of refraction information.

关 键 词：折射信息提取 图像采集 相衬成像技术 摇摆曲线 

分 类 号：O435.1[机械工程—光学工程]