Stabilizing estimate of location of target region inferred from tracked multiple landmark regions of a video image

Any of multiple landmark regions of a scene being viewed by an image sensor are used for interring the location of a target region of the scene in which a pattern is to be inserted in order to avoid the problem of the view of a region being occluded. Because of changes, such as the pointing angle of the sensor, there is a slight difference in size and position in the location of a target region inferred from one landmark region and from another landmark region. this results in a jitter when a first landmark region being used for inferring the location of a target region is replaced by a second landmark region in response to the first landmark region being occluded. This jitter is eliminated by deriving an error-correcting component that compensates for the aforesaid slight difference in size and position in the location of a target region inferred from different landmark regions.