1. A method of controlling an object's motion through a viewed space comprising the steps of: acquiring a stereo image of said viewed space wherein said stereo image comprises an image set; computing a set of 3D features from said stereo image; filtering from said set of 3D features to generate a set of filtered 3D features; computing a trajectory of said set of filtered 3D features; and generating a control signal influencing said objects motion in response to said trajectory.