Shadow and rhythm as sign patterns of obstacle detection

For the navigation of the mobile robot, real time detection methods of moving vehicles and pedestrians are proposed. The method is based on a locomotion strategy, ´sign pattern-based stereotyped motion´. Sign patterns of a moving vehicle is shadow underneath the vehicle which is darker than any stain of the asphalt paved road. The sign pattern of pedestrian is rhythm of walking. Rhythm of walking is unique to the pedestrians, and not influenced by time, weather, sunlight, shadow and distance, moreover it is independent of the clothes the pedestrian puts on.