An approach for the measurement of distance travelled by blind and visually impaired people

The research we are reporting here is part of our effort to develop a navigation system for the blind. Our long-term goal is to create a portable, self contained system that will allow visually impaired individuals to travel through familiar and unfamiliar environments without the assistance of guides. In order to overcome the imperfections of existing electronic travel aids for the blind, this paper describes then, the problem of distance measurement. The proposed system is based on the technique of using an accelerometer and double integrating its output with respect to time. This method suffers from drift problems caused by the double integration and offset of the accelerometer which are overcome by the footswitch. This footswitch is used to allow a PC through an interface card to provide frequent corrections of drift effects. From this study, more compatible navigation aids can be developed for blind pedestrians.