1. Computer Vision Laboratory, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
2. School of Software Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi, China
3. National Key Laboratory of Human-Machine Hybrid Augmented Intelligence, Institute of Artificial Intelligence and Robotics, Xi’an Jiaotong University, Xi’an, Shaanxi, China