1. School of Microelectronics, Xi’an Jiaotong University, Xi’an, China
2. CAS Key Laboratory of Technology in Geo-Spatial Information Processing and Application System, University of Science and Technology of China, Hefei, China
3. School of Engineering Science, Simon Fraser University, Burnaby, BC, Canada
4. Tencent Technologies, Shenzhen, China
5. Google Inc., Mountain View, CA, USA