Homography estimation on the Special Linear group based on direct point correspondence

This paper considers the question of obtaining a high quality estimate of a time-varying sequence of image homographies using point correspondences from an image sequence without requiring explicit computation of the individual homographies between any two given images. The approach uses the representation of a homography as an element of the Special Linear group and defines a nonlinear observer directly on this structure. We assume, either that the group velocity of the homography sequence is known, or more realistically, that the homographies are generated by rigid-body motion of a camera viewing a planar surface, and that the angular velocity of the camera is known.