TY - JOUR
T1 - Reducing Staircasing Artifacts in SPECT Reconstruction by an Infimal Convolution Regularization
AU - Wu , Zhifeng
AU - Li , Si
AU - Zeng , Xueying
AU - Xu , Yuesheng
AU - Krol , A.
JO - Journal of Computational Mathematics
VL - 6
SP - 626
EP - 647
PY - 2016
DA - 2016/12
SN - 34
DO - http://doi.org/10.4208/jcm.1607-m2016-0537
UR - https://global-sci.org/intro/article_detail/jcm/9817.html
KW - SPECT, Infimal Convolution Regularization, Staircasing Artifacts, Fixed-point Proximity Algorithm.
AB - <p style="text-align: justify;">The purpose of this paper is to investigate the ability of the infimal convolution regularization in curing the staircasing artifacts of the TV model in the SPECT reconstruction. We formulate the problem of SPECT reconstruction with the infimal convolution regularization as a convex three-block optimization problem and characterize its solution by a system of fixed-point equations in terms of the proximity operator of the functions involved in its objective function. We then develop a novel fixed-point proximity algorithm based on the fixed-point equations. Moreover, we introduce a preconditioning matrix motivated by the classical MLEM (maximum-likelihood expectation maximization) algorithm. We prove convergence of the proposed algorithm. The numerical results are included to show that the infimal convolution regularization is capable of effectively reducing the staircasing artifacts, while maintaining comparable image quality in terms of the signal-to-noise ratio and coefficient recovery contrast.</p>