Quantitative Comparison of Alternative Sensory Displays for Mobility Aids for the Blind

This paper proposes a method to compare quantitatively various auditory display schemes communicating the course a blind traveler should follow to comply with information a blind mobility aid has acquired, and the optimal scheme is sought for that traveler. A computer system emulates different display devices which use amplitude modulation to indicate the error of a subject´s location from the indicated course. The real-time Selspot-based TRACK system measures the location of the human subject in real time, and the error is presented to the subject via each of the emulated devices. The indicated course, human trajectory, and error are recorded in computer disk memory. The performance of the human in each task is evaluated by calculation of a transfer function of the human with each display and then using this transfer function as the criterion for comparison. The feasibility of designing the display schemes of blind mobility aids using this procedure is demonstrated. Thus, an optimal choice for the specific blind person can be made via this system before committing a particular mobility aid design to the lengthy development process.