Enhanced perception for visually impaired people evaluated in a real time setting

Abstract

Many aids have been proposed for the visually impaired or the blind. The regular cane is widely accepted but has known limitations such as its short length. Numerous approaches such as ultrasound enhanced canes have been developed with limited success, the main reason being the information transfer over the auditory system, one of the most important spatial senses. The AERBUS project proposed to use fast 3D object recognition in conjunction with a priority based information reduction as used in autonomous mobile robotics to generate a virtual velocity map of objects in the surrounding. This information shall be transferred to the cognitive system of the blind via the stimulation of skin receptors. Here we focus on a special belt evaluated in a real time setting. Up to 8 vibration motors as used in mobile phones were integrated into an elastic belt and were controlled simultaneously via a parallel port of a PC. A simple computer game was developed to obtain the real time performance of test subjects and to evaluate different coding schemes. A direct command mode is compared to a local coding that represents the direction towards an object by the position of the motor in the belt, while distance information is transferred by a pulse coding scheme. Non-handicapped students were involved as test subjects. They were facing the task of avoiding collisions in the game. The performance of the individuals was determined with respect to the velocity and the number of objects. The subjects were blinded and information, in this case -recommended actions or object distances- is directly transmitted to the subjects via the vibration motors. With both schemes performance improved significantly. No special training was required and all subjects were able to perform additional tasks while avoiding collisions in the direct command mode. © 2009 Springer-Verlag.