Using geometric corners to build a 2D mosaic from a set of image

The main problem for building a mosaic is the computation of the warping functions (homographies). In fact two cases are to be distinguished. The rst is when the homography is mainly a translation (i.e. the rotation around the optical axis and the zooming factor are small). The second is the general case (when the rotation around the optical axis and zooming are arbitrary). Some eecient methods have been developed to solve the rst case. But the second case is more dif-cult, in particular, when the rotation around the optical axis is very large (90 degrees or more). Often in this case human interaction is needed to provide a rst approximation of the transformation that will bring us back to the rst case. In this article we present a method to solve this problem without human interaction for any rotation around the optical axis and fairly large zooming factors.