1. Research Institute for Artificial Intelligence of Things and the Department of Land Surveying and Geo-Informatics, The Hong Kong Polytechnic University, Kowloon, Hong Kong
2. College of Oceanography and Space Informatics, China University of Petroleum (East China), Qingdao, China
3. Department of Land Surveying and Geo-Informatics, The Hong Kong Polytechnic University, Kowloon, Hong Kong