The Effects of Virtual Reality, Augmented Reality, and Motion Parallax on Egocentric Depth Perception

A large number of previous studies have shown that egocentric depth perception tends to be underestimated in virtual reality (VR) - objects appear smaller and farther away than they should. Various theories as to why this might occur have been investigated, but to date the cause is not fully understood. A much smaller number of studies have investigated how depth perception operates in augmented reality (AR), and some of these studies have also indicated a similar underestimation effect. In this paper we report an experiment that further investigates these effects. The experiment compared VR and AR conditions to two real-world control conditions, and studied the effect of motion parallax across all conditions. Our combined VR and AR head-mounted display (HMD) allowed us to develop very careful calibration procedures based on real-world calibration widgets, which cannot be replicated with VR-only HMDs. To our knowledge, this is the first study to directly compare VR and AR conditions as part of the same experiment.