Ultrasonic (US) and infrared (IR) sensors are
broadly used in mobile applications for distance measurements.
In this project, an obstacle detection system is built based on
these two types of sensors. The system is intended for use by the
elderly and people with vision impairment. The prototype
developed has been tested to detect obstacles and shows
accuracies of 95% to 99% for distance measurements if the
sensor circuits are calibrated properly and their output
linearized. The system also demonstrates good detection for
different obstacle materials (e.g., wood, plastic, mirror,
plywood and concretes) and colors. The minimum size of an
obstacle that the system can detect is 5 cm x 5 cm.