This paper presents an automated calibration method for laser range finders distributed in the environment. The laser range finder has recently been considered to be one of the most useful sensors for applications for Intelligent Space (iSpace) which is a space with many distributed sensors and actuators since it can realize both object tracking and map building. In this research, the object tracking function is used for pose estimation of the sensors. In the proposed method, each sensor first obtains positions of moving objects in the environment in its local coordinate system. If these sensors have overlapping observation regions, position of the same object is acquired as a corresponding point. The relative position and orientation of two laser range finders are then estimated from the set of corresponding points. Finally, poses of the laser range finders with regard to an arbitrary coordinate system are calculated based on the relative pose estimations. The proposed method does not require global positions of objects and information on the objects. In addition, multiple objects can be utilized in order to calibrate laser range finders distributed in a wide area efficiently.
