The effect of isolated disparity on depth perception in real and virtual environments

In this paper, we investigated depth perception in real and virtual environments when binocular disparity is the sole distance cue. The observers were asked to estimate the relative depth of spheres verbally in virtual and actual environments. Constant apparent sized stimuli were used to measure the just-noticeable difference in depth perception, thus avoiding providing a size gradient cue. Results of the experiments revealed individual differences in virtual reality in contrast to reality. Specifically a subgroup of observers had difficulty perceiving the depth of virtual spheres in virtual reality, which may indicate that they rely on apparent size for judging depth. Furthermore, the just-noticeable differences were more variable in the virtual environment than with real objects. Our results reveal individual differences when the disparity-driven convergence cue is the only distance cue provided in virtual reality.