Automatic calibration method of voxel size for cone-beam 3D-CT scanning system  

作　　者：杨民 王晓龙 刘义鹏 孟凡勇 李兴东 刘文丽 魏东波 

机构地区：[1]School of Mechanical Engineering and Automation, Beijing Univ.of Aeronautics and Astronautics [2]Department of Control Science and Engineering,Harbin Institute of Technology [3]State Key Laboratory of Multiphase Complex Systems,Institute of Process Engineering,Chinese Academy of Sciences [4]National Institute of Metrology

出　　处：《Chinese Physics C》2014年第4期69-74,共6页中国物理C（英文版）

基　　金：Supported by National Natural Science Foundation of China(NSFC)(11275019,21106158,61077011);National State Key Laboratory of Multiphase Complex Systems(MPCS-2011-D-03);National Key Technology R&D Program of China(2011BAI02B02);Beijing Municipal Commission of Education(BMCE)Under the Joint-Building Project and National Key Scientific Apparatus Development of Special Item of China(2013YQ240803)

摘　　要：For a cone-beam three-dimensional computed tomography （3D-CT） scanning system, voxel size is an important indicator to guarantee the accuracy of data analysis and feature measurement based on 3D-CT images. Meanwhile, the voxel size changes with the movement of the rotary stage along X-ray direction. In order to realize the automatic calibration of the voxel size, a new and easily-implemented method is proposed. According to this method, several projections of a spherical phantom are captured at different imaging positions and the corresponding voxel size values are calculated by non-linear least-square fitting. Through these interpolation values, a linear equation is obtained that reflects the relationship between the voxel size and the rotary stage translation distance from its nominal zero position. Finally, the linear equation is imported into the calibration module of the 3D-CT scanning system. When the rotary stage is moving along X-ray direction, the accurate value of the voxel size is dynamically exported. The experimental results prove that this method meets the requirements of the actual CT scanning system, and has virtues of easy implementation and high accuracy.For a cone-beam three-dimensional computed tomography （3D-CT） scanning system, voxel size is an important indicator to guarantee the accuracy of data analysis and feature measurement based on 3D-CT images. Meanwhile, the voxel size changes with the movement of the rotary stage along X-ray direction. In order to realize the automatic calibration of the voxel size, a new and easily-implemented method is proposed. According to this method, several projections of a spherical phantom are captured at different imaging positions and the corresponding voxel size values are calculated by non-linear least-square fitting. Through these interpolation values, a linear equation is obtained that reflects the relationship between the voxel size and the rotary stage translation distance from its nominal zero position. Finally, the linear equation is imported into the calibration module of the 3D-CT scanning system. When the rotary stage is moving along X-ray direction, the accurate value of the voxel size is dynamically exported. The experimental results prove that this method meets the requirements of the actual CT scanning system, and has virtues of easy implementation and high accuracy.

关 键 词：cone-beam CT voxel size least square fitting automatic calibration 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]