Developing Unmanned Aerial Vehicles (UAV) with self-stabilization
capabilities represents an intensive research field nowadays. This paper aims to
show that combining our previous horizon extraction algorithm with homography
methods permits to estimate the homography more robustly and thus the UAV
attitude. We show that imposing horizon constraint permits to remove evident
inconvenient non-planar points. Moreover, we explain that computing the horizon
in the sphere permits to compute the normal vector of the ground plane and thus
retrieve the right motion among the four possible solutions obtained by planar
homography, which is not a trivial problem usually.