The Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.
PLoS One. 2013 Jul 3;8(7):e67695. doi: 10.1371/journal.pone.0067695. Print 2013.
Independent navigation for blind individuals can be extremely difficult due to the inability to recognise and avoid obstacles. Assistive techniques such as white canes, guide dogs, and sensory substitution provide a degree of situational awareness by relying on touch or hearing but as yet there are no techniques that attempt to make use of any residual vision that the individual is likely to retain. Residual vision can restricted to the awareness of the orientation of a light source, and hence any information presented on a wearable display would have to limited and unambiguous. For improved situational awareness, i.e. for the detection of obstacles, displaying the size and position of nearby objects, rather than including finer surface details may be sufficient. To test whether a depth-based display could be used to navigate a small obstacle course, we built a real-time head-mounted display with a depth camera and software to detect the distance to nearby objects. Distance was represented as brightness on a low-resolution display positioned close to the eyes without the benefit focussing optics. A set of sighted participants were monitored as they learned to use this display to navigate the course. All were able to do so, and time and velocity rapidly improved with practise with no increase in the number of collisions. In a second experiment a cohort of severely sight-impaired individuals of varying aetiologies performed a search task using a similar low-resolution head-mounted display. The majority of participants were able to use the display to respond to objects in their central and peripheral fields at a similar rate to sighted controls. We conclude that the skill to use a depth-based display for obstacle avoidance can be rapidly acquired and the simplified nature of the display may appropriate for the development of an aid for sight-impaired individuals.
盲人独立导航可能极其困难，因为他们无法识别和避开障碍物。辅助技术，如盲杖、导盲犬和感觉替代，通过依赖触觉或听觉提供一定程度的情境感知，但迄今为止，还没有任何技术试图利用盲人可能保留的任何残余视力。残余视力可能仅限于对光源方向的感知，因此，任何呈现在可穿戴显示器上的信息都必须是有限的且明确的。为了提高情境感知能力，即检测障碍物，显示附近物体的大小和位置，而不是包括更精细的表面细节，可能就足够了。为了测试基于深度的显示器是否可用于导航小型障碍物赛道，我们构建了一个带有深度摄像头和软件的实时头戴式显示器，用于检测到附近物体的距离。距离通过靠近眼睛的低分辨率显示器上的亮度来表示，而没有使用聚焦光学器件的好处。一组有视力的参与者被监测，因为他们学习使用这个显示器来导航赛道。所有人都能够做到这一点，并且随着练习，时间和速度迅速提高，而碰撞次数没有增加。在第二个实验中，一组患有不同病因的严重视力障碍者使用类似的低分辨率头戴式显示器执行搜索任务。大多数参与者能够以与有视力的对照组相似的速度使用显示器来响应他们的中央和外围视野中的物体。我们得出结论，使用基于深度的显示器来避免障碍物的技能可以快速掌握，并且显示器的简化性质可能适合为视力障碍者开发辅助工具。
