根据世界卫生组织的公开数据，全世界约有2.85亿人患有视觉障碍。对于这个庞大的群体而言，日常出行是一项极具挑战的任务。盲道是一种专门为视觉障碍人士设计的公共基础设施，它通过提供脚底的触觉感知从而为视障人士指示一条特定的可行走道路。然而，盲道的实际使用受到了很多局限，例如铺设不规范、被障碍物阻挡、表面纹理磨损和较为有限的覆盖范围。为了解决这些问题，我们提出了虚拟盲道，旨在通过多模态反馈方式向视觉障碍人士呈现出平滑的可行走道路，从而辅助他们完成独立出行任务。虚拟盲道的实现依赖于三个技术：环境感知、路线规划、和信息反馈。在信息反馈层面，很少有工作在如何引导用户沿着目标路线平滑高效行走的问题上展开研究。本工作将研究重点聚焦于反馈设计上，即如何将已经规划好的目标道路告知给难以通过视觉获取信息的视障人士，以引导用户安全、流畅、高效地沿着目标道路行走。 在这项工作中，我们进行了三项用户实验。首先，我们以视障人士对盲道的实践经验和常见问题为基础，提取了虚拟盲道的设计准则。其次，我们通过与视障人士的共同研讨与设计，开发了一个多模态的反馈解决方案。该方案包括：（1）提供易于感知方向的肩部和腰部的振动触觉反馈界面；（2）用以描述用户前方道路状况的音频反馈界面。最后，我们通过用户实验对该解决方案进行了评估。在多模态反馈方式的引导下，16名视觉障碍参与者成功完成了128次试验中的127次，试验环境采用的基本道路宽度为2.1米，包含了直线和曲线道路。另外，主观反馈表明，我们设计的虚拟盲道解决方案易于学习，能够帮助用户流畅地完成行走任务。本文也讨论了虚拟盲道在真实环境中提供导航的可行性和潜在的局限性。
According to the World Health Organization, an estimated 285 million people worldwide are visually impaired. This vast population is faced with daily challenges in mobility tasks.Tactile pavings are public works for visually impaired people, designed to indicate a particular path to follow by providing haptic cues underfoot. However, they face many limitations such as installation errors, obstructions, degradation, and limited coverage. To address these issues, we propose Virtual Paving, which aims to assist independent navigation by rendering a smooth path to visually impaired people through multi-modal feedback. Virtual Paving relies on three techniques: sensing, planning, and rendering. In the aspect of rendering, few existing systems successfully enabled users to follow a continuous path (with both straight paths and turns) smoothly and efficiently. This work assumes that a path has been planned to avoid obstacles and focuses on the feedback design to guide users along the path safely, smoothly, and efficiently. In this work, we conducted three user studies. Firstly, we extracted the design guidelines of Virtual Paving based on an investigation into visually impaired people's current practices and issues with tactile pavings. Next, we developed a multi-modal solution through co-design and evaluation with visually impaired users. This solution included (1) vibrotactile feedback on the shoulders and waist to give readily-perceivable directional cues and (2) audio feedback to describe road conditions ahead of the user. Finally, we evaluated the proposed solution through user tests. Guided by the designed feedback, 16 visually impaired participants successfully completed 127 out of 128 trials with 2.1m-wide basic paths, including straight and curved paths. Subjective feedback indicated that our solution to render Virtual Paving was easy for users to learn, and it also enabled them to walk smoothly. The feasibility and potential limitations for Virtual Paving to support independent navigation in real environments are discussed.
