二维CT系统周向运动误差的角坐标系模型  

Model of angular coordinates for circumferential motion error of two-dimensional computed tomography system

作　　者：赵飞[1] 谢里阳[1] 李佳[1] 张子骞[1] 

机构地区：[1]东北大学机械工程与自动化学院,沈阳110004

出　　处：《中国体视学与图像分析》2015年第4期378-383,共6页Chinese Journal of Stereology and Image Analysis

摘　　要：对CT系统现场进行空间分辨率评定,已形成了较为完整的评价体系。但对正在设计的CT系统,某些因素引起的空间分辨率下降,如由检台旋转运动引起的周向误差,目前暂无统一的方法进行方案评估。本文针对二维CT系统的周向运动误差,建立了原点不在图像中心点的角坐标系模型。并在该坐标系下定义了角卷积运算,推导了理想冲激点的表达式和基本性质及其对任意函数的分解。该模型可作为二维CT周向运动误差点扩展函数推导和重建象质分析的基础。The spatial resolution of CT system is evaluated according to a relatively complete evaluation sys- tern. However for the CT system which is being designed, there is no unified method to evaluate the spatial resolution deterioration caused by some factors such as the circumferential error caused by the rotation of the test platform. In this paper, a model of angular coordinates is set up for evaluation of the circumferential motion error in two-dimensional CT system, in which the origin is not at the center of the image. In the an- gular coordinates, angular convolution is defined, the expression and the basic properties of the ideal im- pulse point and the decomposition of arbitrary functions are derived. This model can be used as the basis for the derivation of the point spread function and quality analysis of the reconstructed image of the circum-ferential motion en＇ors in two-dimensional CT systems.

关 键 词：二维CT 空间分辨率 周向运动误差 角坐标系 原点偏置 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]