Applications of non-metric vision to some visual guided tasks

Presents a stratification of geometric information available from stereovision in three levels: Euclidean, affine and projective, depending upon the kind of calibration that has been obtained for the stereo rig. The authors then focus on the last two levels: they show how affine calibration can be achieved from real images without the need of calibration patterns and how to use projective and affine information to determine, for example, whether an obstacle is coming too close to the stereo rig or the middle of a corridor or a road.