An iterative algorithm for computed tomography image reconstruction from limited-angle projections

摘要

In application of tomography imaging, limited-angle problem is a quitepractical and important issue. In this paper, an iterativereprojection-reconstruction (IRR) algorithm using a modified Papoulis-Gerchberg(PG) iterative scheme is developed for reconstruction from limited-angleprojections which contain noise. The proposed algorithm has two iterativeupdate processes, one is the extrapolation of unknown data, and the other isthe modification of the known noisy observation data. And the algorithmintroduces scaling factors to control the two processes, respectively. Theconvergence of the algorithm is guaranteed, and the method of choosing thescaling factors is given with energy constraints. The simulation resultdemonstrates our conclusions and indicates that the algorithm proposed in thispaper can obviously improve the reconstruction quality.