基于射线路径的快速迭代CT重建

Fast Iterative CT Reconstruction Based on the Path of Ray

针对ART-TV算法重建耗时问题,提出一种基于射线穿过物体路径的快速迭代CT重建算法。首先,提出一种基于射线穿过物体路径的投影数据排序访问方式。通过优先计算各角度下穿过物体路径长度较长射线的投影过程,提高重建迭代效率。同时,提出一种与射线选取次数成反比的松弛因子,可在迭代初期加快收敛速度,并避免在后期陷入局部收敛。Shepp-Logan实验表明,本算法重建时间明显缩短,计算速度提高了28.61%。可在保证图像质量前提下,有效提高重建迭代速度。

In order to improve the computational efficiency of the ART-TV algorithm,a fast iterative reconstruction algorithm based on the path length of ray passing through the detected object is proposed.Firstly,a sort selection access method for projection data based on the path length of ray passing through the detected object is presented.The projection process of ray with longer path length through the object at different angles is calculated firstly to accelerate the reconstruction iteration speed.Moreover,a relaxation factor,which is inversely proportional to the number of ray selection is also proposed,so that the convergence speed can be accelerated at the beginning of iteration and local convergence can be avoided at the end of iteration.The Shepp-logan experiment showed that the reconstruction time of the proposed algorithm was significantly shortened and the computing speed improved by 28.61%.The proposed algorithm greatly improves the iterative efficiency of reconstruction without reducing the image quality.