Robotic Sensing for the Guidance of the Visually Impaired
This paper describes ongoing work into a portable mobility aid, worn by the
visually impaired. The system uses stereo
vision and sonar sensors for obstacle avoidance and recognition of
kerbs. Because the device is carried the user is given freedom of
movement over kerbs, stairs and rough ground, not traversable with a
wheeled aid. Motion in the sensor due to the walking action has been
modelled and is tracked to allow compensation of sensor measurements. The vision obstacle detection method uses
comparison of image feature disparity with a ground feature disparity
function. The disparity function is continually updated by the
walk-motion model and by scene ground-plane fitting. World primitives are segmented by motion
and grouped. The walker motion model allows more meaningful tracking
of mobile world objects. Kerb detection is achieved by identifying
clusters of parallel lines using the Hough transform. Some results are
described from the vision and sonar parts of the system.