CHS: Small: Realistic Navigation in the Third Dimension Using Low Cost, Portable, Wearable Immersive Environment Systems

Miami University, Oxford OH

Investigators

Abstract

The natural world around us is characterized by hills and valleys. Man-made structures are often composed of multiple levels connected by stairways, ramps, or ladders. Slope helps us remain oriented when navigating, and has a strong influence on the routes people elect to follow towards their destinations. To date, however, the simulation of incline and elevation changes has largely been neglected in immersive environments (IEs), resulting in 2D navigation through a 3D world. The downside of this situation is that immersed users receive a less than realistic experience and do not learn to take advantage of vertical information typical of real world situations; moreover, route learning and navigation can become behaviorally inaccurate when users are able to effortlessly glide up inclines that might otherwise require a detour. Historical solutions to this problem are typically comprised of expensive, heavy, and complex hardware such as a tilting treadmill or active mechanical tether; such systems require design tradeoffs that may excel at simulating one type of motion (e.g., an incline) while neglecting others (e.g., turning), and the specialized hardware has generally not matured beyond the lab. The PI's prior research has been aimed at creating low-cost, high-fidelity, and portable IE systems that incorporate a rendering unit and a head-mounted display with a natural locomotion interface that allows users to navigate through virtual worlds by walking and turning normally. In this project the PI will build upon and extend that work by implementing realistic simulations of slope and changing elevation. Project outcomes will benefit cognitive and behavioral research on human spatial memory and learning, as well as IE training for tasks involving route selection, general navigation, multi-level travel, and slope perception. Recent research has demonstrated that software-based redirected walking techniques can subtly distort an IE (e.g., by imperceptibly rotating the virtual world about the user or scaling user movement), to enable kilometer-scale navigation in a confined tracking area. The PI will build on these techniques to simulate slope with simple inexpensive hardware. The effort required to walk up or downhill will depend upon factors such as weight, stride length, motion efficiency, speed, incline, and distance, as one would expect in the natural world and which can easily be measured in an IE. Although the physical surface under the user cannot be tilted in a wearable IE system, it is possible to scale user movement to enforce an appropriate amount of physical effort. Moreover, the PI and his team have developed a unique high-precision locomotion interface comprised of low cost foot-mounted inertial/magnetic sensors that can precisely track a user's gait and stepping pattern to measure the amount and direction of force, and can detect atypical stepping actions such as those associated with stairs or ladders. System validation will be carried out through a series of behavioral studies, in which subjects complete spatial perception and navigation tasks in corresponding real and immersive environments that include slope and/or various artefacts that lead to changes in elevation.