Real-Time Gaze Holding in Binocular Robot Vision

• Authors: David J. Coombs
• Venue: Real-Time Gaze Holding in Binocular Robot Vision
• Year: 1992

Using a binocular, maneuverable visual system, a robot that holds its gaze on a visual target can enjoy improved visual perception and performance in interacting with the world. This dissertation examines the problem of holding gaze on a moving object from a moving platform, without requiring the ability to recognize the target. A novel aspect of the approach taken is the use of controlled camera movements to simplify the visual processing necessary to keep the cameras locked on the target. A gaze holding system on the Rochester robot''s binocular head demonstrates this approach. Even while the robot is moving, the cameras are able to track an object that rotates and moves in three dimensions. .pp The key observation is that visual fixation can help separate an object of interest from distracting surroundings. Camera vergence produces a horopter (surface of zero stereo disparity) in the scene. Binocular features with no disparity can be extracted with a simple filter, showing the object''s location in the image. Similarly, an object that is being tracked will be imaged near the center of the field of view, so spatially-localized processing helps concentrate on the target. Rochester''s binocular robot exploits these observations. The vergence and smooth tracking systems cooperate to hold the cameras on an object moving in three dimensions. The vergence system changes the vergence angle of the cameras to drive the disparity of the target to zero, relying on the tracking system to keep the target in the central field of view. The tracking system centers the cameras on the zero-disparity signals, relying on the vergence system to hold vergence on the target. Instead of requiring a way to recognize the target, the system relies on active control of camera movements and binocular fixation segmentation.