1. Key Laboratory of Optoelectronic Technology & Systems (Ministry of Education), College of Optoelectronic Engineering, Chongqing University, Chongqing 400044, China
2. ICT NDT Engineering Research Center, Ministry of Education, Chongqing University, Chongqing 400044, China
3. College of Optoelectronic Engineering, Chongqing University of Posts and Telecommunications, Chongqing, 400065, China