A REGISTRATION METHOD FOR RIGID OBJECTS USING REPULSIVE FORCE

A method to register the position and posture of a rigid object which moves in three-dimensional space, without points and/or vector matchin g between before and after the movement is described. In the method, a group of coordinates of representative points of the object in the in itial state, P-i(x(i), y(i), z(i)) (i = 1 to n), and those after the m ovement P-j(x(j), y(j), z(i)) (j = 1 to n), are used for the input dat a without knowing their point correspondences. Firstly, the object is translated from the initial position so that its centroid coincides wi th one of the goal positions. The difference in posture of the object is corrected by rotating round the centroid by the torque which attrac ts it to the goal posture. It is demonstrated that repulsive forces to each point of the object from all points at the goal posture, whose m agnitude is the square of the distance between the points, satisfactor ily produce such torque. The practical procedures for determining the position and posture using this principle are described, together with their characteristics and examples of applications to actual data.