Determining 3-D location parameters of a cylindrical object

For a robot, to fetch the desired object, it is necessary to determine the object's location relative to the robot, and calculate the orientation of the object. Many of these objects are of cylindrical shape, for example, cylindrical containers with harmful liquid on a desk, cylindrical bottles with drink on the shelf, etc. In this paper, a simple geometrical method is proposed to determine the location, the radius and the orientation of a known height cylindrical object in the 3-D space. This object location determination problem is the equivalence of the problem of robot location by the use of the cylindrical object. Here, any object that has a cylindrical portion is defined as the cylindrical object and such objects are frequently seen in real environment. By integrating image processing techniques, 3-D vector analysis and simple algebraic computation, the system can achieve high speed requirement in determining the location and the orientation of the object. The approach has the advantage that it does not require the values of any intrinsic camera parameters. Experimental results for the desired object taken in different positions show that the computing time for location and orientation determination is about 1.2 sec in a 20 MHZ IBM compatible PC/AT computer system and the measurement error is less than 5% on the average.