用几何参数表方法实现快速重建 CT 图象  

Fast reconstruction CT image by using geometric parameter table

作　　者：张朝宗[1] 郭志平[1] 董宇峰[1] 张和平[1] 

机构地区：[1]清华大学核能技术设计研究院

出　　处：《清华大学学报（自然科学版）》1998年第7期47-49,共3页Journal of Tsinghua University(Science and Technology)

基　　金：国家"八六三"项目

摘　　要：在微机上进行图象重建可增加ＣＴ系统的灵活性并降低造价，但必须选择适当的算法并改进计算程序，才能达到一个可以接受的计算速度。提出了的基于“旋转极坐标反投影”概念的几何参数表方法，即提前将投影地址和反投影权重计算好，以表格形式存放，在反投影过程中仅需查表调用，可避免在反投影过程中进行大量费时的计算，从而大大减少了计算工作量。几何参数表方法对二维及三维图象重建都可应用，实验结果说明采用几何参数表后，至少可减少反投影时间一个数量级。实现了在微机上快速重建ＣＴ图象。Reconstructing image on a microcomoputer is able to increase flexibility for the CT system and to reduce cost, however, it can not be acceptable unless the CT systems have tolerable calculating speed. For this reason it is necessary to select appropriate algorithm and to improve calculating program. This paper presents the geometric parameter table method based on the concept of rotating polarcoordinate back projection, i.e., calculating the data of projection addresses and back projection weights in advance, saving them in form of parametertable, in course of back projection the work which only needs to do by computer is to look up the table. This method avoids huge timeconsuming calculation in the course of back projection, thus the amount of calculation is greatly reduced. The geometric parameter table method is applicable to both 2D and 3D image reconstruction. The results show that by using geometric parameter table the time for back projection is reduced by a factor of 10 at least. Fast reconstructing CT image on a microcomputer is realized.

关 键 词：计算机断层成象 图象重建 几何参数表 

分 类 号：TP391.5[自动化与计算机技术—计算机应用技术] TP391.41[自动化与计算机技术—计算机科学与技术]