CALIBRATION OF A COMPUTER-CONTROLLED ROBOTIC VISION SENSOR WITH A ZOOM LENS

Active vision sensors are increasingly being employed in vision system s for their greater flexibility. For example, vision sensors in hand-e ye configurations with computer controllable lenses (e.g., zoom lenses ) can be set to values which satisfy the sensing situation at hand. Fo r such applications, it is essential to determine the mapping between the parameters that can actually be controlled in a reconfigurable vis ion system (e.g., the robot arm pose, the zoom setting of the lens) an d the higher-level viewpoint parameters that must be set to desired va lues (e.g., the viewpoint location, focal length). In this paper we pr esent calibration techniques to determine this mapping. In addition, w e discuss how to use these relationships in order to achieve the desir ed values of the viewpoint parameters by setting the controllable para meters to the appropriate values. The sensor setup that is considered consists of a camera in a hand-eye arrangement equipped with a lens th at has zoom, focus, and aperture control. The calibration techniques a re applied to the H6 x 12.5R Fujinon zoom lens and the experimental re sults are shown. (C) Academic Press, Inc.