Towards a 2D tactile vocabulary for navigation of blind and visually impaired

In this paper we present research work towards a 2D tactile vocabulary for training visually impaired for their independent mobility. The vocabulary is associated to a 2D tactile array (vibration array), which is a part of a wearable navigation prototype (Electronic Travel Aid) called Tyflos. The vibration array is currently consisting of 16 vibrating elements arranged in a 4×4 manner. Each motor can be independently driven with square pulses of varying frequencies. The vibration array can represent dynamically the 3D space of the user´s field of view: the 2D arrangement represent the x-y coordinates while the frequencies represent the z coordinate (which is the distance of an obstacle from the user). Different navigation and human factor criteria have been used to create the 2D tactile vocabulary. Finally, using the continuous feedback from the users, the goal is to balance between a minimal vocabulary for easy learning and a rich vocabulary that will still be able to represent efficiently the 3D navigation space.