Junction view densities in images

Line sketch images of real objects in a scene may contain junctions that represent corners of objects. The work reported in the paper shows how measures of the angles at a junction provide information concerning the structure of physical corners. The authors concentrate on the corners of a cube and derive the probability view densities of the corner angles under isotropic positioning of the viewpoint. Interpretation of the results shows that non-general viewing positions are quite likely, and that such placements of the viewpoint should not be treated as pathological when interpreting line sketches or analyzing scenes.<>