Egocentric distance perception and performance of direct pointing in stereoscopic displays.

In this study, the interaction performances and spatial perceptions in stereoscopic environments were investigated. The experiment compared direct user interactions during pointing at a target, which was continuously visible or presented briefly and disappeared, in both stereoscopic and real environments, at three parallax/depth levels. The position data, collected by a motion system, were used to compute accuracy, signed error, movement time, and throughput. The results showed inaccurate egocentric distance judgment in stereoscopic displays and accurate perceptions in the real world. The overall inaccuracy, which was overestimation of about 10 cm, was relatively better than that achieved in previous studies. The overestimation decreased as the egocentric distance increased. However, providing visual objects did not improve the accuracy. The study concluded that direct pointing could minimize the underestimation problems commonly reported in stereoscopic viewing studies and showed practical significance for developers to focus on incorporating more direct and natural human-virtual reality interactions for improved performance. The findings of this study provide insight towards the development of less expensive displays and their applications. Implications of this work and engineering solutions are also discussed.