Advanced electronic mobility aids for visually-impaired people

In the last three decades, there have been many studies on developing electronic aids for visually impaired people[1,2]. These studies have led to the developments of electronic products like the Sonic Torch (TM), the Sonic Glasses (TM), the Mowat Sensor (a small hand-held device which detects objects by sending out brief pulses) and the Sonic Pathfinder (worn on a head band, it emits ultra-sound and gives the user feedback through earphones, the lower the note the closer the user is to an object). These aids were designed to be used in conjunction with guide dogs or with canes. Although these products are successful in achieving improved mobility, they have not so far provided a desirable performance mainly due to reliability problems and the extensive training required. Today, with the advances in signal processing both in algorithms and in supporting hardware, a much higher resolution acoustic imaging and object classification can be achieved. However, most of these new technologies are directed towards Robot's guidance systems, object identification in industrial environment and underwater target identification and very little has been published on implementing these new technologies to improve the mobility of visually impaired people[3,4,5,6,7]. In this paper, we present a review of advanced high resolution acoustic imaging together with advanced pattern recognition and object classification techniques and show how these techniques can be used to improve the mobility of visually impaired people in different environment.