1. School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
2. Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
3. Institute of Marine Equipment, Shanghai Jiao Tong University, Shanghai 200240, China.