1. Graduate Institute of Optoelectronic Engineering, National Chung Hsing University, Taichung, Taiwan
2. Electrical Engineering Department, National Chung Hsing University, Taichung, Taiwan
3. Graduate Institute of Biomedical Engineering, National Chung Hsing University, Taichung, Taiwan
4. Graduate Institute of Optoelectronic Engineering and the Electrical Engineering Department, National Chung Hsing University, Taichung, Taiwan