摘要
图像重建是将二维投影数据转换为三维体数据的数学过程。分析图像重建算法性能的常用手段是数值仿真,而获取数字体模的投影数据是仿真实验的第一步。Shepp-Logan体模应用最为广泛,本文首先介绍三维Shepp-Logan体模及其改进形式。重点讨论在任意扫描轨迹下三维Shepp-Logan体模的投影方法。并运用该方法模拟了工业CT中常用的圆轨迹与螺旋轨迹成像过程。数值分析结果显示,两种扫描轨迹得到的重建图像均方误差均小于2‰,本文的方法可以达到较高的精度。
Image reconstruction is a mathematic process which reconstructs three-dimensional volume data from two-dimensional projections. Numerical simulation is always used to study the characteristics of some reconstruction algorithm, in which projection simulation of some numerical phantom is the first step. The Shepp-Logan phantom is the most widely used in the field of Computed Tomography （CT）. In this paper, parameters of the three-dimensional Shepp-Logan phantom and its modified forms are introduced firstly. Secondly, a projection simulation method of the three-dimensional Shepp-Logan phantom on general scan trajectory is presented. Thirdly, projections of the three-dimensional Shepp-Logan phantom in circular and helical scans are simulated using the proposed method. Then, the FDK algorithm and helical-FDK algorithm are employed to deal with these projections, respectively. Experimental results show that the mean square errors between the reconstructed images and numerical phantoms are both less than 2‰, and indicate that the presented method has higher accuracy.
出处
《CT理论与应用研究（中英文）》
2013年第3期469-477,共9页
Computerized Tomography Theory and Applications
基金
国家高技术研究发展计划"863计划"(2012AA011603)
