DSP-based ultrasonic navigation aid for the blind

This paper introduces a novel navigation aid for the blind designed at our laboratory. The system detects obstacles in front of the user by the help of ultrasonic echolocation and indicates the distance and horizontal position of the nearest detected object by spatial stereo sound effects. The instrument is based on a fixed-point digital signal processor. The applied object-localization method as well as the principle of the binaural audio feedback are discussed. Also, the operation and structure of the hardware are briefly introduced. Finally, some measurement results on an experimental device are reported.