A new navigation method is described for an indoor mobile robot. The robot system is composed of a Radio Frequency Identification (RFID) tag sensor and a commercial three-wheel mobile platform with ultrasonic rangefinders. The RFID tags are used as landmarks for navigation and the topological relation map which shows the connection of scattered tags through the environment is used as course instructions to a goal. The robot automatically follows paths using the ultrasonic rangefinders until a tag is found and then refers the next movement to the topological map for a decision.
Our proposed technique would be useful for real-world robotic applications such as intelligent navigation for motorized wheelchairs.
This paper describes a new method for getting 3D information on planar surfaces and cylindrical objects in a scene. The sensor system consists of two CCD cameras with near infrared filters and two point light sources which are virtually placed at the projection center of each camera. The light sources are switched on alternately, and images under each lighting are recorded with the cameras. Under a point light source, even on a planar surface, there is a distribution of luminance due to diffuse and specular reflections. Since the light is emitted from the projection center, the positions of the peak of the luminance distribution on each surface directly provide information on the radius and center of a cylinder and the orientation and perpendicular distance to a plane. Our approach is based on locating the peak positions in the images.
Since the cameras detect only the near infrared spectrum of the reflected light from object surfaces, colored textures on the surfaces fade away in the images. The surfaces become nearly solid and the luminance distributions become much clearer compared with the images formed by visible rays of light. Therefore, luminance distributions even on texture surfaces can be extracted without complex image processing for analyzing texture images. The equipment setup for emitting light from the projection center is very simple and the illuminators can be easily set up at ordinary TV cameras. The proposed technique would be useful for describing the 3D skeleton structures of scenes. The experimental results show that the method is adequate for such purposes.