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

我们周围的自然界以丘陵和山谷为特征。人造结构通常由多个楼层组成，通过楼梯、坡道或梯子连接。坡度帮助我们在航行时保持定向，并对人们选择的通往目的地的路线有很大的影响。然而，到目前为止，在沉浸式环境(IES)中对坡度和高程变化的模拟在很大程度上被忽略了，导致在3D世界中进行2D导航。这种情况的不利之处是，沉浸在其中的用户获得的体验不太现实，无法学习利用现实世界中典型的垂直信息；此外，当用户能够毫不费力地滑上可能需要绕道的斜坡时，路线学习和导航可能会变得不准确。以往对这一问题的解决方案通常由昂贵、笨重且复杂的硬件组成，例如倾斜跑步机或主动机械系绳；此类系统需要在设计上权衡权衡，这种折衷可能擅长模拟一种运动类型(例如倾斜)而忽略其他类型的运动(例如转弯)，而且专门的硬件通常还没有成熟到实验室之外。PI之前的研究旨在创造低成本、高保真和便携的IE系统，该系统集成了渲染单元和具有自然运动界面的头盔显示器，允许用户通过正常行走和转弯在虚拟世界中导航。在这个项目中，PI将通过实施逼真的坡度模拟和改变高程来建立和扩展这项工作。项目成果将有助于对人类空间记忆和学习的认知和行为研究，以及涉及路线选择、一般导航、多层次旅行和坡度感知任务的IE培训。最近的研究表明，基于软件的重定向行走技术可以微妙地扭曲IE(例如，通过围绕用户不知不觉地旋转虚拟世界或缩放用户移动)，以在受限的跟踪区域中实现千米级导航。PI将建立在这些技术的基础上，用简单而廉价的硬件来模拟斜坡。上山或下山所需的努力将取决于重量、步长、运动效率、速度、倾斜和距离等因素，正如人们在自然界中所预期的那样，这些因素很容易在IE中测量。虽然在可穿戴的IE系统中，用户下方的物理表面不能倾斜，但可以缩放用户的移动以施加适量的体力。此外，PI和他的团队开发了一种独特的高精度移动界面，由低成本的脚载式惯性/磁性传感器组成，可以精确跟踪用户的步态和步态模式，以测量力的大小和方向，并可以检测非典型的步态动作，如与楼梯或梯子相关的动作。系统验证将通过一系列行为研究进行，受试者在相应的真实和身临其境的环境中完成空间感知和导航任务，其中包括导致海拔变化的坡度和/或各种人工制品。

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.