基于正弦图恢复的CT局部重建算法

CT Local Reconstruction Algorithm Based on Sinogram Restoration

针对局部扫描过程中投影数据沿探测器方向截断的特点,提出一种基于正弦图数据恢复的扇束CT局部重建算法.算法首先基于截断正弦图提取的边缘信息对缺失投影数据进行扩充,接下来对未扩充完整的零值区域利用两侧已知的投影数据进行线性插值,最后依据扩充完整的投影数据经滤波反投影重建出局部图像.仿真和临床数据的重建结果表明,算法对直接利用局部截断投影数据重建图像中呈现的环形伪影有明显的抑制作用,且重建图像边缘清晰.

Aiming at the truncation characteristics of projection data along the detector direction during local scanning,a CT local reconstruction algorithm based on sinogram data restoration was proposed.The algorithm firstly augments the missing projection data based on the edges extracted from the truncated sinogram.Then,the unexpanded complete zero-value region was linearly interpolated using the projection data on both sides.Finally,the local region of interest image was reconstructed by filtered back projection according to the expanded complete projection data.The reconstruction results of simulation and clinical data show that the algorithm has obvious inhibitory effect on the ring artifacts in the reconstructed image from the local truncated projection data not being augmented,and the edges of the reconstructed image are clear.