1. Professor, Dept. of Engineering Mechanics, Hohai Univ., 1 Xikang Rd., Nanjing 210098, China (corresponding author).
2. Ph.D. Student, School of Optical-Electrical and Computer Engineering, Univ. of Shanghai for Science and Technology, Shanghai 200093, China; Senior Engineer, Shanghai Underground Infrastructure Safety Inspection and Maintenance Equipment Engineering Technology Research Center, 1239 Siping Rd., Shanghai 200092, China.
3. Master Student, Shanghai Underground Infrastructure Safety Inspection and Maintenance Equipment Engineering Technology Research Center, 1239 Siping Rd., Shanghai 200092, China.