1. Institute of Image Processing and Pattern Recognition, Shanghai Jiao Tong University; Shanghai 200240 China
2. Key Laboratory of System Control and Information Processing, Ministry of Education of China; Shanghai 200240 China
3. National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Science; Shanghai 200083 China
4. Department of Computational Medicine and Bioinformatics; University of Michigan; Ann Arbor Michigan 48109