1. Department of Automation and Computer-Aided Engineering, The Chinese University of Hong Kong, N. T., Hong Kong
2. Department of Automation and Computer-Aided Engineering, The Chinese University of Hong Kong, N. T., Hong Kong, Department of Opto-Electronic Engineering, ChongQing University, Chong Qing, China 400044
3. Department of Opto-Electronic Engineering, ChongQing University, Chong Qing, China 400044