Image-based positioning with respect to a non-structured scene using 2D image motion

Visual servoing based upon geometrical features such as image points coordinates is now well set on. Nevertheless, this approach has the drawback that it usually needs visual marks o n the observed object to retrieve geometric features. T h e idea developed here is that these features can be retrieved by integrating dynamic ones, which can be estimated without any a priori knowledge of the scene. Thus, more realistic scenes can be used to achieve vision-based control such as positioning tasks. W e show that a n affine model is insuf ic ient to ensure convergence and that a quadratic one is needed. Finally, results are presented related t o the positioning with respect t o a complex scene.