1. An iterative method of estimating the pose of a PTZ camera while it is moving, said method comprising: (a) using an image registration method on a reference image and a current image to calculate a matrix that estimates the motion of sets of points corresponding to the same object in said reference image and said current image; said iterative method characterized by the following additional steps: (b) using information about the absolute camera pose, embedded in said matrix to simultaneously recalculate both the starting positions in said reference image and said motion estimate; (c) using said recalculated starting positions and said recalculated motion estimate to determine the pose of said camera in said current image; (d) taking said current image as a new reference image, selecting a new current image and repeating steps (a) to (c) to determine the pose of said camera in said new current image; and (e) repeating step (d) until said camera stops moving.