1. Institute of Information Science, Beijing Jiaotong University, Beijing 100044, China
2. College of Electronic and Information Engineering, Hebei University, Baoding 071000, China
3. Machine Vision Technology Innovation Center of Hebei Province, Baoding 071000, China
4. The State Key Laboratory of Multimodal Artificial Intelligence Systems, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China