SYSTEM FOR DIGITIZING THE TRAJECTORY OF A TARGET POINT OF A MOVING BEAM

The trajectory across a surface of an intended target point of a moving beam directed toward the surface is digitized by finding a particular point along each of a plurality of parallel axes of the surface for which a two-dimensional convolution integral of two functions is a maximum. A first of the two functions is the instantaneous intensity distribution of the beam on the surface with respect to the instantaneous position of the target point on the surface. The second function is the average beam intensity distribution on the surface produced as the beam moves across the surface during a finite period. A digital data sequence is generated in which each element thereof represents the position on the surface of a separate one of the particular points determined in this fashion, and this sequence represents the trajectory of the target point of the beam on the surface.