We propose the use of co-occurrence matrices/histograms (of relative distan
ce, relative angle) between pairs of orientation tokens for silhouette reco
gnition and texture discrimination. The orientation tokens are defined as t
he tangent vectors to the boundary of the silhouette, or the gradient vecto
rs for grey images. The efficiency of the method is demonstrated with the h
elp of three different series of experiments with real data. (C) 1998 Elsev
ier Science B.V. All rights reserved.