用查找表和极坐标反投影法实现计算机断层扫描快速重建

FAST COMPUTED TOMOGRAPHY RECONSTRUCTION WITH LOOK-UP TABLE AND POLAR COORDINATE BACK-PROJECTION

为了在普通PC机上实现计算机断层扫描 (CT)快速重建 ,提出了利用查找表和极坐标反投影快速重建方法。该方法首先在极坐标系下利用查找表实现快速反投影 ,然后将极坐标反投影数据映射到笛卡尔坐标系中 ,在此过程中 ,又一次运用查找表技术实现快速插值 ,有效地节约了时间。计算机仿真结果表明 ,该方法不但大大提高了重建速度 ,而且重建质量与传统卷积反投影相当 ,尤其当重建图像尺寸较小时 。

In order to realize CT fast reconstruction on an ordinary PC, a fast reconstruction process using look-up table and polar coordinate back-projection was presented. Fast back-projection is first executed with the look-up table in polar coordinates. Reconstruction of the image in Cartesian coordinates is then carried out when the look-up table is used again to realize the fast interpolation. Computer simulation proved that the method could speed up image reconstruction effectively and the quality of the image was close to the result of conventional back projection (CBP). When the size of the image is not large, the process can well replace the conventional means.