1. Tokyo Polytechnic University, Faculty of Engineering, 1583, Iiyama, Atsugi-shi, Kanagawa 243-0297, JapanbTopcon Corporation, 75-1, Hasunuma-cho, Itabashi-ku, Tokyo 174-8580, Japan
2. Tokyo Polytechnic University, Faculty of Engineering, 1583, Iiyama, Atsugi-shi, Kanagawa 243-0297, Japan