Vision-based Detection of Stair-cases

Stair-cases are useful environmental landmarks for navigation in mobility aids for the partially sight- ed. In this paper, a texture detection method using Gabor Filters is proposed to detect dis- tant stair-cases. When close enough, stair-cases are then detected by looking for groups of con- current lines, where convex and concave edges are partitioned using intensity variation informa- tion. Stair-case pose is estimated by a homogra- phy search approach. Using an a priori stair-case model, search criteria and constraints are estab- lished to find its vertical rotation and slope. These algorithms have been applied to both synthetic and real images with promising results.