1. Key Laboratory of Intelligent Perception and Image Understanding of Ministry of Education, School of Artificial Intelligence, Xidian University, Xi’an, China
2. College of Computer Science and Electronic Engineering, Hunan University, Changsha, China
3. Zhejiang Laboratory, Hangzhou, China
4. Department of Computer Science, Institute of Transportation Studies, University of California at Irvine, Irvine, CA, USA