Multiscale filter bank approach to camera-movement control in active vision systems

Active vision systems faced with the problem of searching for targets in natural scenes are finding space variant sensors increasingly important. A popular class of space variant sensors are those based on the structure of the primate retina: they have a small area near the optical axis of greatly increased resolution (the fovea) coupled with a gradual falloff in resolution as one moves towards the periphery. In such systems, a primary requirement is an efficient mechanism for targeting the optical axis to different points of interest in the visual world. In this paper, we describe a robust and efficient paradigm for achieving foveal targeting by making use of iconic scene descriptions comprised of the responses of a bank of steerable filters at multiple scales and orientations. The filter bank description is rotation and scale invariant, occlusion tolerant, and view-insensitive to a considerable extent. We describe procedures for robustly matching vectors of a previously foveated point to instances of the point in other possibly transformed images obtained after camera motion. In such situations, the multiscale structure of the filter bank lends itself naturally to an efficient targeting mechanism for the space variant sensor.