Research On Simultaneous Iterative Algorithms For Image Reconstructions

ABSTRACT:The Computerized Tomography (CT), theoretically addressed as the image reconstruction from projection data, is a significant research method and extensively applicable technology in both scientific and industrial engineering domains.In image reconstruction based on the iterative algorithms, The main iterative algorithms are Algebra Reconstruction Technique (Art), Simultaneous Iterative Reconstruction Technique (Sirt) and Block Iterative Reconstruction Technique. Using perfect Iteration parameter can improve the Convergence rate, reduce the computation time and reduce the errors.This paper studies the relaxation parameter’s selection in the Cimmino iterative algorithms. We get a relaxation parameter method by studying the formula x(n+1)=x(n)+λnA*(b-A(n)), When the complete projection data are collected, we can obtain a better results of the numerical experiments. In addition, this paper also studied the use of EM algorithms for partial reconstruction, According to the numerical experiment, We found that the reconstructed image generates the unknown constant bias in general. But after edge extension, we can get better results than the former, If we subtract a constant offset of center pixel of the image, The resulting image is closer to the original image.