The design of telepresence systems: the task-dependent use of binocular disparity and motion parallax

The effect of different visual depth cues presented through a head-mounted display in a dark (no pictorial cue) environment was investigated. The relative effects of binocular disparity, motion parallax, and a combination of the 2, were assessed for 3 tasks at 2 viewing distances. These tasks (which varied in the minimum amount of information they required) were a nulling task, setting a triangle to be equilateral and matching the base-to-apex magnitude of 2 triangles at different distances. Performance within the tasks varied considerably but was most accurate for the nulling task. Differences between viewing conditions may be due to a failure in the assessment of absolute viewing distance. It is argued that these results are task specific. Although there was some variation between different cue types, they appear to be largely interchangeable within the tasks. These results have implications for system designers selecting an appropriate display device for a telepresence system.