This paper presents an algorithm for extracting regions and subsequent
ly labelling line segments in images. the algorithm is implemented for
a stereo system that consists of a verging pair of cameras mounted on
a mobile robot. The focus of the paper is on the description of an al
gorithm that uses the geometrical layout of line segments in an image
to attach a label to each line segment: boundary, join or isolated. Th
is line labelling is then used in conjunction with the planar regions
within each image of a stereo pair to facilitate high level stereo mat
ching.