How taxel-based displaying devices can help visually impaired people to navigate safely

This paper reports on the studies we are conducting to help visually impaired people in the challenging task of safely navigating in a partially or totally unknown environemnt. We present here some results showing how a single taxel-based display can participate to acquire geometrical information of the environment dealing with low level navigation. Specifically, we designed a mouse-shaped device, which allows users to navigate in a virtual environment mirroring real sites. In the design, we first quantify users tactile intrinsic sensitivity in terms of the well known JND (just noticeable difference). We then move to qualify the device in a simple height classification task. This allows to see how users utilize our device for the simplest low level navigation task, i.e. determining if a straight pathway is free of obstacles or not. In a third experiment, we test a combination of memorization and localization processes, namely objects recognition and reconstruction tasks. This help us to verify or/and establish hypotheses on how users construct a model of their surroundings while navigating. Finally we test a complex task including objects recognition and obstacles avoidance within a realistic environment.