1. Department of Electrical and Electronic Engineering, The Hong Kong Polytechnic University, Hong Kong
2. National Key Laboratory for Multimedia Information Processing and National Engineering Research Center of Visual Technology, School of Computer Science, Peking University, Beijing, China
3. Tsinghua Shenzhen International Graduate School, Tsinghua University, China
4. School of Computing and Mathematical Sciences, University of Leicester, Leicester, U.K.
5. School of Computer Science and Technology, Ocean University of China, Qingdao, China