1. Beijing Key Laboratory of Embedded Real-time Information Processing Technology, Beijing Institute of Technology, Beijing, China
2. State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, Wuhan, China
3. Beijing Institute of Technology Chongqing Innovation Center, Beijing Institute of Technology, Chongqing, China
4. Department of Computer Science and Technology, Tsinghua University, Beijing, China