The Importance of Stereo and Eye-Coupled Perspective for Eye-Hand Coordination in Fish Tank VR

It is possible to simulate a high-quality virtual environment with viewpoint-controlled perspective, high-quality stereo, and a sense of touch obtained with the PHANToM force feedback device using existing “fish tank VR” technologies. This enables us to investigate the importance of different depth cues and touch using higher quality visual display than is possible with more immersive technologies. Prior work on depth perception suggests that different depth cues are important depending on the task performed. A number of studies have shown that motion parallax is more important than stereopsis in perceiving 3D patterns, but other studies suggest that stereopsis should be critically important for visually guided reaching. A Fitts' Law tapping task was used to investigate the relative importance of stereo and head tracking in visually guided hand movements. It allowed us to examine the intertap intervals following a head movement in order to look for evidence of rapid adaptation to a misplaced head position. The results show that stereo is considerably more important than eye-coupled perspective for this task, and that the benefits increase as task difficulty increases. Disabling stereo increased mean intertap intervals by 33%, while disabling head tracking produced only an 11% time increase. However, we failed to find the expected evidence for adaptation during the series of taps. We conclude by discussing the theoretical and practical implications of the results.