(1980-1990). In order to make intelligent mobile robots, it is indispensable to have a visual system that can automatically make a map of the environment ahead that is to be traversed. We have been developing an intelligent vision system named MARS (map realization system).

Photo. 1 shows the first prototype of a range finder that is configured by an orthodox laser slit optical scanner and a CCD camera. In 1985, such functions as a map configuration method to estimate occluded area by utilizing accumulated knowledge were introduced.

Photo. 2 indicates a range finder developed in 1987 that utilizes weak laser light (1 mW) that is safe for the human eye, and is capable of measurement under sun light. Conventional range finders do not normally operate under powerful ambient light such as sunlight. As indicated in Figs. 1 and 2, to manifest functions that will eliminate powerful ambient light, this device utilizes interference type optical filters, the DDD method which selectively detects only the positive pulse signals, and the false correspondence elimination method that uses signals from two redundant CCD cameras.

Photo. 3 is the "MAC (Multiple Arrayed Camera) vision" developed in 1989. Multiple cameras are arranged at equal intervals in parallel as shown in Fig. 4(a). When simultaneously scanning with these cameras, signals from a light source have a tendency to line up linearly as in Fig. 4(b). Utilizing this characteristic, if the number of cameras is increased as in (c) and (d), and judged whether signals are detected on the position of the scanning line on the decision is made to then false correspondences can be eliminated. This　system detects the signals at the timing of single scan, and then calculates their position coordinates while it is scanning next. As this measurement and calculation process repeats successively, it has real time measurement function of 3D positioning of 1800 points per screen with the rate of 16 screens per second.

References:

1. Shigeo Hirose, Kazuhiro Yoshida, Kan Taguchi : The Study of a Map Realization System (Cancellation of Ambient Light and Swaying Motion of a Robot), Advanced Robotics, 2, 3, pp.259-276 (1987)
2. Kazuhiro Yoshida, Shigeo Hirose : Laser Triangulation Range Finder Available Under Direct Sunlight, Proc. ICRA, Philadelphia, pp.1702-1707 (1988)
3. Shigeo Hirose, Kazuhiro Yoshida, Yasumasa Toratani : The Study of a Map Realization System : Consideration of Real-Time Map Generation, Advanced Robotics, 4, 3, pp.223-242 (1990)
4. Kazuhiro Yoshida, Shigeo Hirose : Real-Time Stereo Vision with Multi-Arrayed Camera, Proc. ICRA, Nice, France, pp.1765-1770 (1992)