1. School of Mathematics and Statistics, Institute for Information and System Sciences, Xi’an Jiaotong University, Xi’an, China
2. Department of Mathematics and Statistics, University of Ottawa, Ottawa, Canada
3. School of Biomedical Engineering, Southern Medical University, Guangzhou, China
4. Shenzhen Institutes of Advanced Technology, Paul C. Lauterbur Research Center for Biomedical Imaging, Chinese Academy of Sciences, Shenzhen, China