A method and apparatus is disclosed for identifying a position of an object in
free space using a video image wherein the object is comprised of at least three
equidistantly spaced, co-linear beads. The video image is captured on a view plane
of a video camera system and represented on a frame memory thereof. Relative positions
of the beads on the frame memory are determined and corresponding coordinate positions
of the beads in the free space are calculated based upon the determined relative
spacings and known camera system geometries. The object may also include an alignment
indicator so that the pointing direction of the object can be determined.
