Evaluating Stereo and Head-Coupled Perspective Cues in Collaborative Immersive Environments

The concept of virtual reality relies heavily on stereoscopic and perspective-correct vision. While their importance for single-user setups has been well studied, there is a need to investigate their importance for collaborative immersive environments, especially as multi-user virtual environments become more prevalent. Both stereoscopy, which refers to 3D depth perception through binocular disparity of images in the two eyes, and head-coupled perspective, which is generated by motion and temporal changes in retinal images, provide robust cues for depth perception, figure-ground separation, and 3D shape perception. In our study with 60 participants, we manipulated stereo and perspective cues in a two-user scenario (decision-maker and helper) and measured performance (i.e. accuracy and reaction time) and cyber-sickness in four constellations: both stereo and head-coupled perspective are offered vs. only stereo vs. only head-coupled perspective vs. neither cue is offered. Our results show a differentiated picture: performance in terms of accuracy and reaction time was best when both cues were provided. Stereoscopy had a greater impact on accuracy, while head-coupled perspective had a greater impact on reaction times. Cyber sickness depended on the user’s role, with the decision-maker role presenting significantly more difficulty than the helper role. The simultaneous presence of cues from both the stereo and head-coupled perspectives was associated with the least amount of cyber sickness compared to all other constellations.