基于最小三维凸包的锥束CT快速重建方法  

A Faster Image Reconstruction Method for Cone-Beam CT Using Smallest 3D Convex Package of Measured Object

作　　者：李明君[1] 张定华[1] 黄魁东[1] 张顺利[1] 查方龙[1] 

机构地区：[1]西北工业大学现代设计与集成制造技术教育部重点实验室,陕西西安710072

出　　处：《西北工业大学学报》2011年第1期68-73,共6页Journal of Northwestern Polytechnical University

基　　金：西北工业大学基础研究基金(JC200934);西北工业大学研究生创业种子基金(Z2011080)资助;陕西省自然科学基金(2009JQ8017)

摘　　要：针对传统锥束CT重建全尺寸立方体空间时存在大量冗余计算的问题,文章提出一种基于被测物体最小三维凸包的快速重建方法。首先根据Z线优先重建算法的特性,给出最小三维凸包的定义,然后根据锥束CT扫描投影关系和最小三维凸包的投影特点,提出了确定最小三维凸包3个参数的相应算法,最后通过仅重建最小三维凸包内的体素的方法,显著减少了重建计算量。对于截面形状变化较大的被测物体,可采用分段确定最小三维凸包的方式进一步减少计算冗余。2组仿真实验结果表明,文中方法可有效提高锥束CT的重建速度,并对复杂被测物体具有良好的适应性。The introduction of the full paper reviews a number of papers in the open literature on fast image recon- struction and then proposes what we believe to be a faster reconstruction method, which is explained in sections 1 and 2. Section 1 presents the characteristics of the Z-line data priority reconstruction algorithm. The core of section 2 consists of： （ 1 ） we give the definition of the smallest 3D convex package, which is shown in Fig. 3 ; （2） on the basis of the projection relationship of cone-beam CT and the characteristics of the smallest 3D convex package of measured object, we put forward the algorithm for determining its three basic parameters; （3） we reconstruct only the voxels inside the smallest 3D convex package, thus greatly reducing its computational redundancy; for the com- plicated measured objects with varying cross-section shapes, we determine the smallest 3D convex packages section by section to further reduce their computational redundancy. To verify the effectiveness of our method, section 3 presents two sets of numerical simulation examples ; the simulation results, given in Figs. 5 and 6 and Table 1, and their analysis show preliminarily that our method can effectively enhance the reconstruction speed of cone-beam CT and has good adaptability for complicated object measurement.

关 键 词：图像重建 算法 锥束CT 最小三维凸包 Z线优先重建 

分 类 号：TG115.28[金属学及工艺—物理冶金] TP391[金属学及工艺—金属学]