1. School of Computer Science and Engineering, North Minzu University, Yinchuan 750021, China
2. Key Laboratory of Images & Graphics Intelligent Processing of State Ethnic Affairs Commission, North Minzu University, Yinchuan 750021, China
3. School of Science, Ningxia Medical University, Yinchuan 750004, China
4. School of Electronic & Information Engineering, Suzhou University of Science and Technology, Suzhou 215009, China
5. Department of Urology, The General Hospital of Ningxia Medical University, Yinchuan 750004, China
6. Key Laboratory of Spectral Imaging Technology CAS, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an 710119, China
7. School of Public Health and Management, Ningxia Medical University, Yinchuan 750004, China