An audiodisplay tool for visually impaired people: the sound screen system

The aim of this contribution is to present a flexible realtime system designed for vision rehabilitation using sensory substitution. In this version, the developed substitutive sensory system is restricted to graphical information. The system is based on some findings in psychoacoustics obtained from actual experiments. It is based on the auditive localization of virtual sound sources. This system consists of four loudspeakers located at the four comers of a square in the vertical plane in front of the listener. The basic idea is to construct an input-output mapping which converts graphical input information into localized sound source. The shapes of graphical forms are then converted into sounds produced by moving a virtual source. The displacement in azimuth and elevation on the plan defined by the four loudspeakers of this virtual sound source allows different shapes to be drawn. The temporal integration by the listener of successive positions occupied by this virtual sound source describes the global graphic object. The system has been successfully evaluated through experiments involving a small group of sighted and blind subjects.