1. Tokyo Institute of Technology, Imaging Science and Engineering Laboratory, 4259-R2-51, Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
2. Tokyo Institute of Technology, Global Scientific Information and Computing Center, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8550, Japan
3. Keio University, Department of Pathology, School of Medicine, 35 Shinanomachi, Shinjyuku, Tokyo 160-8582, Japan