The Effects of Avatars, Stereo Vision and Display Size on Reaching and Motion Reproduction

Abstract

Thanks to recent advances on motion capture devices and stereoscopic consumer displays, animated virtual characters can now realistically interact with users in a variety of applications. We investigate in this paper the effect of avatars, stereo vision and display size on task execution in immersive virtual environments. We report results obtained with three experiments in varied configurations that are commonly used in rehabilitation applications. The first experiment analyzes the accuracy of reaching tasks under different system configurations: with and without an avatar, with and without stereo vision, and employing a 2D desktop monitor versus a large multi-tile visualization display. The second experiment analyzes the use of avatars and user-perspective stereo vision on the ability to perceive and subsequently reproduce motions demonstrated by an autonomous virtual character. The third experiment evaluates the overall user experience with a complete immersive user interface for motion modeling by direct demonstration. Our experiments expose and quantify the benefits of using stereo vision and avatars, and show that the use of avatars improve the quality of produced motions and the resemblance of replicated msotions; however, direct interaction in user-perspective leads to tasks executed in less time and to targets more accurately reached. These and additional tradeoffs are important for the effective design of avatar-based training systems.

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

“…Similar methods were applied in a more recent study by Lin and Woldegiorgis to report egocentric distance estimation in a depth plane of a virtual environment. Furthermore, reaching with vision was reported to be better and smoother and using avatars and haptic feedback, Camporesi and Kallmann and Corbett et al, respectively, claimed that the quality of motions has been improved. To accommodate the considered distance, the hand reaching was extended by holding pointing sticks, at which reflective markers were attached at their tips.…”

G6-1 Analysis of movement and performance of pointing in real and stereoscopic environments

“…Generally, the direct pointing by holding a stick that was used in this study could be one of the reasons for the comparable performances, which emphasizes the positive futures of more natural interactions. The findings of Camporesi and Kallmann (2016) who found better accuracy of direct interactions in 3D environments supported the claim. The movement behavior depicted in both environments was also similar, greatly characterized by only one peak.…”

Using Several Types of Virtual Characters in Sports - a Literature Survey

“…Ida (2015) demonstrated 3D laser scanning, where face morphing, muscle activity and wrinkles can be implemented. Camporesi and Kallmann (2016) stated that today's VCs in sports do not have facial expressions and eye movements, but stiff, blanc faces with only few details, so that the users do not get disturbed. However, Kibele (2006) and Prigent et al (2015) doubted the importance of facial expressions and eye movements in sports, because athletes rely more on kinematic information for correct anticipation and response behavior.…”

“…So far, no review article focused on VCs in sports although recent research detected that VCs are essential to improve performance in VR (e.g. Camporesi & Kallmann, 2016, Gonzalez-Lanier & Franco, 2017.…”