Real and virtual nature of image edges intersections

Edges intersect in an edge image and this intersection point may correspond to 3-D point joining two straight lines in the real world scene and those lines represent a real object plane; in this case it is called a real lines intersection, otherwise it is called a virtual intersection. An automatic system for locating image lines is likely to produce many virtual intersections and so despite many studies in the field of boundary recognition, the question of whether the intersection of two lines in an image of a 3-D scene corresponds to a real object point still merits further investigation. This paper presents a computational technique to identify the real or virtual nature of the edge intersections. The discrimination is based on rectified images obtained from a pair of uncalibrated images. The method is tested using deferent types of images of real scenes. The results obtained showed reliable decisions.