The accuracy of distance perception in the frontal plane of projection-based stereoscopic environments

An experiment was conducted to investigate the accuracy of distance judgment in a frontal plane of projection-based stereoscopic environments. The targets were presented at nine distinct frontal plane positions and at three depth levels. Eighteen right-handed participants with self-declared normal visual acuity reached the target, either continuously visible or presented briefly, by holding pointing sticks. All combinations of the experimental conditions were repeated for an equivalent real-world environment. Accuracies of judgments were then computed from three-dimensional data collected by a motion system composed of six infrared cameras. As compared with about 94% accuracy in the physical world, the space in the frontal plane was only about 85% on the stereoscopic environment. The result also revealed more accurate judgment in the continuous presence of the target. Furthermore, the accuracy was affected by the egocentric distance of the frontal plane from the position of the participant. The study concluded that the compression in the frontal plane and underestimation of depth, which has been reported by the majority of previous studies could be an indication that the space compression in virtual environments might be in all the three-dimensions. These findings can be used as guidelines for developers and content designers to properly locate virtual targets and selection of efficient interaction modes.