A multisensor electronic traveling aid for the visually impaired

Abstract

BACKGROUND: Identifying obstacles and potholes in the pathway of the visually impaired have received much attention. While much has been done on the detection of obstacles, in the design of electronic mobility aids, much more is needed to be done on the detection of holes and drop-offs, especially those that are affordable and hands-free. This paper therefore considers the development of a wearable electronic mobility aid. METHODS: The developed system is based on the multisensor fusion approach of detection which combined three techniques, namely: a source of laser light, a camera and an ultrasonic sensor. A red line generating laser source is used to project a straight line and this is captured by the camera. The red line is deformed differently on coming in contact with holes or standing obstacles. The pattern of deformation is then extracted for obstacle and pothole recognition. The visibility of laser light is greatly reduced when the scene is extremely illuminated, so this is complemented with edge detection. The edge detection uses edges in the identification of holes and obstacles. This is combined with ultrasonic sensing, so that the presence of obstacles can be differentiated from that of holes. The outcome of detection and the distance of obstacles from the blind are relayed via an audio cue. REDULTS: Its evaluation showed better performance compared to the guide cane. It showed a reduction in collision rate by 83.25% and reduction in falling rate by 84.62%. The device received good acceptability from the users.