A stereo vision system for position measurement and recognition in an autonomous robotic system for carrying food trays

This paper describes a practical stereo vision system for position measurement and recognition in an autonomous food-tray-carrying robot. Our food tray carrying robot delivers and collects food trays in medical care facilities. The vision system must position and recognize tables and trays for the robot to manipulate the trays. We developed edge detecting techniques for the measurement of target objects that vary in terms of brightness using correlation operations. We fabricated a compact environmental perception unit using a real-time image correlation processor (the color tracking vision) and had it installed on the food carrying robot. Tray delivery and collection experiments in simulated environment show that the unit can position the tables and the food trays accurately enough to manipulate the trays in varying degrees of brightness (60 to 7200 1x) using video images from a pair of stereo cameras installed on the gripper of the manipulator