1. Graduate School of System Informatics, Department of Systems Science, Kobe University 1 , Rokkodai 1-1, Nada, Kobe 657-8501, Japan
2. Center of Optical Scattering Image Science, Kobe University 2 , Rokkodai 1-1, Nada, Kobe 657-8501, Japan
3. Department of Applied Bioscience, Kanagawa Institute of Technology 3 , Atsugi 243-0292, Japan