Abstract
Previous research has shown that the use of stereoscopic displays and observer-produced motion parallax in telepresence systems can each improve operators' performance beyond that achieved using conventional 2-D displays. Enhancing stereo disparity and motion parallax through increased inter-camera distance or camera movement respectively may confer further benefits both in laboratory and applied tasks. In experiment 1 the inter-camera distance was doubled to provide enhanced stereo disparity. Using 3 laboratory depth tasks (depth nulling, matching depth, and depth setting) under minimal cue conditions, performance improved compared to normal stereo disparity. Experiment 2 amplified motion parallax (gain set to 2), using the same tasks, leading to better performance compared to control conditions. Experiment 3 investigated the effects of enhanced motion parallax in a place-and-pick task which is frequently used to assess surgical performance. Working under full view conditions, participants had to pick up small objects from one place and drop them through apertures in another, using surgical forceps. The main result was that amplified motion parallax did not improve performance compared to a standard motion parallax condition. The main finding is that the provision of self-produced motion parallax alone, or in combination with binocular information, adds nothing to performance. While enhanced depth information produced benefits in the laboratory, the surgical task, to novice operators at least, did not benefit from any form of motion parallax (enhanced or not). The problem with using motion parallax as a depth cue in this more realistic task is probably one of motor coordination: as the participant moves his or her head, the rest of the body moves too, including the arm used to position the object. Thus potential visual benefits may be without corresponding performance benefits due to the detrimental effects of head and body movement on motor coordination.