Vision is the principal source of information of the surrounding world. It facilitates our movement and development of everyday activities. In this sense, blind people have great difficulty for moving, especially in unknown environments, which reduces their autonomy and puts them at risk of suffering an accident. Electronic Travel Aids (ETAs) have emerged and provided outstanding navigation assistance for blind people. In this work, we present the methodology followed for implementing a stereo vision-based system that assists blind people to wander unknown environments in a safe way, by sensing the world, segmenting the floor in 3D, fusing local 2D grids considering the camera tracking, creating a global occupancy 2D grid, reacting to close obstacles, and generating vibration patterns with an haptic belt. For segmenting the floor in 3D, we evaluate normal vectors and orientation of the camera obtained from depth and inertial data, respectively. Next, we apply RANSAC for computing efficiently the equation of the supporting plane (floor). The local grids are fused, obtaining a global map with data of free and occupied areas along the whole trajectory. For parallel processing of dense data, we leverage the capacity of the Jetson TX2, achieving high performance, low power consumption, and portability. Finally, we present experimental results obtained with ten (10) participants, in different conditions, with obstacles of different height, hanging obstacles, and dynamic obstacles. These results show high performance and acceptance by the participants, highlighting the easiness to follow instructions and the short period of training.

中文翻译：

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基于视觉的系统，可帮助盲人安全地在未知环境中游荡

视觉是周围世界的主要信息来源。它促进了我们的运动和日常活动的发展。从这个意义上讲，盲人很难行动，特别是在未知的环境中，这降低了他们的自主性，使他们有遭受事故的危险。电子旅行辅助工具（ETA）应运而生，并为盲人提供了出色的导航帮助。在这项工作中，我们介绍了用于实施基于立体视觉的系统的方法，该系统可帮助盲人以安全的方式漫游未知的环境，方法是感知世界，以3D分割地板，融合本地2D网格（考虑到摄像头跟踪），创建一个全局占用2D网格，对接近的障碍物做出反应，并通过触觉带生成振动模式。为了分割3D地板，我们分别评估从深度和惯性数据获得的相机的法向矢量和方向。接下来，我们将RANSAC应用于有效计算支撑平面（地板）的方程。融合局部网格，从而获得包含沿整个轨迹的自由区域和占用区域的数据的全局地图。对于密集数据的并行处理，我们利用Jetson TX2的容量，实现了高性能，低功耗和便携性。最后，我们介绍了十（10）名参与者在不同条件下使用不同高度的障碍物，悬挂障碍物和动态障碍物获得的实验结果。这些结果表明，参与者表现出很高的绩效和接受度，突出了遵循说明的便利性和较短的培训时间。