A Tool for Range Sensing and Environment Discovery for the Blind

This paper describes the development of a hand-held environment discovery tool for the blind. The final device will be composed of a laser-based range sensor and of an onboard processor. As the user swings the hand-held system around, he/she will receive local range information by means of a tactile interface. In addition, the time profile of the range will be analyzed by the onboard processor to detect environmental features that are critical for mobility, such as curbs, steps and drop-offs. In our current implementation, range is collected by a short-baseline triangulation system formed by a point laser and a miniaturized camera, producing readings at frame rate. An Extended Kalman filter is used to track the range data and detect environmental features of interest.