Reorientation during Body Turns

Bruder G, Steinicke F, Hinrichs K H, Lappe M

Abstract

Immersive virtual environment (IVE) systems allow users to control their virtual viewpoint by moving their trackedhead and by walking through the real world, but usually the virtual space which can be explored by walking isrestricted to the size of the tracked space of the laboratory. However, as the user approaches an edge of the trackedwalking area, reorientation techniques can be applied to imperceptibly turn the user by manipulating the mappingbetween real-world body turns and virtual camera rotations. With such reorientation techniques, users can walkthrough large-scale IVEs while physically remaining in a reasonably small workspace.In psychophysical experiments we have quantified how much users can unknowingly be reoriented during bodyturns. We tested 18 subjects in two different experiments. First, in a just-noticeable difference test subjects hadto perform two successive body turns between which they had to discriminate. In the second experiment subjectsperformed body turns that were mapped to different virtual camera rotations. Subjects had to estimate whetherthe visually perceived rotation was slower or faster than the physical rotation. Our results show that the detectionthresholds for reorientation as well as the point of subjective equality between real movement and visual stimulidepend on the virtual rotation angle.