1. Imaging Science and Engineering Laboratory, Tokyo Institute of Technology 4259-J3-15, Nagatsuta, Midori-ku, Yokohama 226-8503, Japan
2. University of Electro-Communications, 1-5-1 Chofugaoka, Chofu-shi, Tokyo 182-8585, Japan
3. Science and Technology Research Laboratories, Japan Broadcasting Corporation, 1-10-11 Kinuta Setagaya, Tokyo 157-8510, Japan