1. School of Automation Engineering, University of Electronic Science and Technology of China, Chengdu, Sichuan, China
2. Key Laboratory of Non-Destructive Testing Technology, Fujian Polytechnic Normal University, Fuzhou, Fujian, China
3. School of Electrical Engineering and Information, Southwest Petroleum University, Chengdu, Sichuan, China
4. School of Engineering, Newcastle University, Newcastle upon Tyne, U.K.
5. School of Engineering, Sichuan University, Chengdu, Sichuan, China