1. School of Communication and Information Engineering and the Center for Information Geoscience, University of Electronic Science and Technology of China, Chengdu, China
2. School of Resource and Environment and the Center for Information Geoscience, University of Electronic Science and Technology of China, Chengdu, China
3. College of Computer Science, Sichuan University, Chengdu, China
4. College of Optoelectronic Engineering, Chengdu University of Information Technology, Chengdu, China