Waxman and Sinha 1986 : A new concept in passive ranging for moving objects is described which is based on the comparison of multiple image flows. If a static scene is viewed by an observer undergoing a known relative translation through space, then the distance to objects in the scene can be easily obtained from the measured from the measured image velocities associated with features on the objects (i.e., motion stereo). The basic theory of this ranging process is presented, along with some examples of simulated scenes. Potential applications are in autonomous vehicle navigation (with one fixed and one movable camera mounted on the vehicle), coordinated motions between two vehicles (each carrying one fixed camera) for passive ranging to moving targets, and in industrial robotics (with two cameras mounted on different parts of a robot arm) for intercepting moving workpieces.