Sparse-View X-Ray CT Reconstruction Using L1 Regularization with Learned Sparsifying Transform

ll Yong Chun, Xuehang Zheng, Yong Long, Jeffrey Fessler


Published in:Fully3D 2017 Proceedings


A major challenge in X-ray computed tomography (CT) is to reduce radiation dose while maintaining high quality of reconstructed images. To reduce the radiation dose, one can reduce the number of projection views (sparse-view CT); however, it becomes difficult to achieve high quality image reconstruction as the number of projection views decreases. Researchers have shed light on applying the concept of learning sparse representations from (high-quality) CT image dataset to the sparse-view CT reconstruction. We propose a new statistical CT reconstruction model that combines penalized weighted-least squares (PWLS) and `1 regularization with learned sparsifying transform (PWLS-ST-`1), and an algorithm for PWLS-ST-`1. Numerical experiments for sparse-view CT show that our model significantly improves the sharpness of edges of reconstructed images compared to the CT reconstruction methods using edgepreserving hyperbola regularizer and `2 regularization with learned ST.
ll Yong Chun
The University of Michigan, USA
Yong Long
University of Michigan - Shanghai Jiao Tong University Joint Institute, China
Xuehang Zheng
University of Michigan - Shanghai Jiao Tong University Joint Institute, China
Jeffrey Fessler
The University of Michigan, USA
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