摘要
工业CT检测对象的尺寸千差万别,为了实现对大尺寸工件的CT成像,探测器偏置扫描、转台偏置扫描是实现工业CT大视野扫描成像的常用手段。在探测器尺寸有限的情况下,为了实现工业CT扫描视野的级联递增,本文提出了转台单侧多次偏置扇束扫描方式以及一种新的重建算法。首先,将转台在不同位置处采集的扇束投影重排为平行束投影;然后,再将分段平行束投影拼接为完整的平行束投影;接下来,再根据平行束投影数据的冗余性,对投影数据进行归一化加权;最后,采用平行束重建算法得到重建图像。本文采用转台单侧三次偏置扫描技术,实现了直径超过1500mm的扫描视野。结果证明,上述方法在扩大扫描视野的同时,能够获得准确的CT重建图像。
The samples to be inspected by industrial CT(ICT)can be of variable sizes.Detector dis-placed scan and off-centered rotation and translation scan are two common techniques applied for enlarging the field of view of ICT.We propose a fan beam multi-scan model and a corresponding reconstruction algorithm in this paper to successively enlarge the field of view conditioned on a limited size detector.In our method,fan beam projections acquired at various positions of rotation table are firstly rebinned into parallel beam projections.Then,sections of parallel beam projections are patched together to constitute complete parallel beam projections.They are further weighted for data normalization based on redundant analysis.Finally,parallel beam reconstruction algorithm is used to get an image.An experiment with three scans of off-centered rotation and translation is conducted in this paper.The diameter of the field of view is more than 1500 mm.The experimental result shows that the method proposed in this paper can get an accurate reconstruction with the field of view enlarged.
作者
陈云斌
王远
李寿涛
CHEN Yunbin;WANG Yuan;LI Shoutao(Institute of Applied Electronics,CAEP,Mianyang 621900,China;National X-ray Digital Imaging Instrument Centre,Mianyang 621000,China)
出处
《中国体视学与图像分析》
2019年第4期380-388,共9页
Chinese Journal of Stereology and Image Analysis
基金
四川省重点研发项目(No.18ZDYF)。
关键词
工业CT
转台偏置
重排
平行束重建
industrial CT
off-centered rotation translation
rebin
parallel beam reconstruction
