Yu Hengyong, Wei Yuchuan, Hsieh Jiang, Wang Ge
CT/Micro-CT Lab, Department of Radiology, University of Iowa, Iowa City 52242, USA.
IEEE Trans Med Imaging. 2006 Jun;25(6):792-803. doi: 10.1109/tmi.2006.875424.
A basic assumption in the classic computed tomography (CT) theory is that an object remains stationary in an entire scan. In biomedical CT/micro-CT, this assumption is often violated. To produce high-resolution images, such as for our recently proposed clinical micro-CT (CMCT) prototype, it is desirable to develop a precise motion estimation and image reconstruction scheme. In this paper, we first extend the Helgason-Ludwig consistency condition (HLCC) from parallel-beam to fan-beam geometry when an object is subject to a translation. Then, we propose a novel method to estimate the motion parameters only from sinograms based on the HLCC. To reconstruct the moving object, we formulate two generalized fan-beam reconstruction methods, which are in filtered backprojection and backprojection filtering formats, respectively. Furthermore, we present numerical simulation results to show that our approach is accurate and robust.
经典计算机断层扫描（CT）理论中的一个基本假设是，在整个扫描过程中物体保持静止。在生物医学CT/微型CT中，这一假设常常不成立。为了生成高分辨率图像，比如用于我们最近提出的临床微型CT（CMCT）原型，开发一种精确的运动估计和图像重建方案是很有必要的。在本文中，当物体发生平移时，我们首先将Helgason-Ludwig一致性条件（HLCC）从平行束几何扩展到扇形束几何。然后，我们提出了一种仅基于HLCC从正弦图估计运动参数的新方法。为了重建运动物体，我们制定了两种广义扇形束重建方法，分别为滤波反投影和反投影滤波格式。此外，我们给出了数值模拟结果，以表明我们的方法准确且稳健。
