利用投影数据重排进行锥形束体积重建的改进算法

针对锥顶轨迹为单圆的锥形束体积重建问题，提出了一种基于平板检测器的T-FDK算法．不同于传统的FDK算法，该算法首先将锥形束投影数据重排为倾斜平行投影数据，然后再经过加权滤波和反投影重建，最后重建出待测物体的三维结构．数据仿真实验结果表明，该算法在保持与传统FDK算法有相同的计算复杂度的同时，重建图像的质量有了明显的提高，可以确保在较大的锥角范围内获得满意的重建图像．因而该算法在医学成像和无损探伤等领域具有重要的实用价值．

Improved cone-beam reconstruction algorithm with projection data rebinning

A volumetric reconstruction algorithm named FT-FDK (flat-panel based tent FDK algorithm) is presented based on the ideas of Grass's T-FDK algorithm. The X-ray projection data were collected on a flat panel detector instead of a cylinder detector,which was quite different from Grass's algorithm. The 2-D projects were obtained along a single circular source trajectory. Unlike traditional FDK algorithm,there are three steps in this new algorithm. Firstly,the projection data should be rebinned to oblique parallel projection data. Then,the rebinned oblique parallel projection data are pre-weighting filtered. Finally,the filtered projection data are backprojected to the final 3-D reconstructed image data. Theory and experimental results show that the algorithm has the same computational complexity as traditional FDK algorithm while the image quality can be improved in the reconstruction. Results suggest that the algorithm can be widely used in applications of medical imaging and nondestructive testing.