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

我们周围的自然世界以丘陵和山谷为特征。 人造结构通常由楼梯、坡道或梯子连接的多个楼层组成。 坡度帮助我们在导航时保持方向感，并对人们选择前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（IE）中，倾斜和海拔变化的模拟在很大程度上被忽视了，导致在3D世界中的2D导航。 这种情况的缺点是，沉浸式用户接收到的体验不太真实，并且没有学会利用真实的世界情况下典型的垂直信息;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在行为上变得不准确。 该问题的历史解决方案通常包括昂贵、沉重和复杂的硬件，例如倾斜跑步机或主动机械系绳;这样的系统需要在模拟一种类型的运动（例如，斜坡）而忽略其它（例如，车削），并且专用硬件通常在实验室之外尚未成熟。 PI先前的研究旨在创建低成本，高保真和便携式IE系统，该系统包含渲染单元和头戴式显示器，具有自然运动界面，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将通过实施坡度和高程变化的逼真模拟来建立和扩展这项工作。 项目成果将有利于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、通用导航、多层次旅行和坡度感知等任务的IE培训。最近的研究表明，基于软件的重定向行走技术可以巧妙地扭曲IE（例如，通过不可察觉地围绕用户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更大规模的导航。 PI将建立在这些技术的基础上，用简单廉价的硬件来模拟斜率。 向上或向下行走所需的努力将取决于诸如体重、步幅、运动效率、速度、倾斜度和距离等因素，正如人们在自然世界中所期望的那样，并且可以在IE中容易地测量。 虽然在可穿戴IE系统中用户下方的物理表面不能倾斜，但是可以缩放用户移动以强制适当量的体力。 此外，PI和他的团队开发了一种独特的高精度运动界面，由低成本的脚上惯性/磁性传感器组成，可以精确跟踪用户的步态和步进模式，以测量力的大小和方向，并可以检测非典型的步进动作，例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的和沉浸式环境中完成空间感知和导航任务，这些环境包括坡度和/或导致海拔变化的各种人工制品。

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.