1. College of Computer Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, China
2. Guangxi Key Laboratory of Image and Graphic Intelligent Processing, Guilin University of Electronic Technology, Guilin, China
3. School of Computer Science and Technology, Harbin Institute of Technology (Shenzhen), Shenzhen, China
4. School of Information Technology, Deakin University, Burwood, VIC, Australia