Computation of Binary Objects Sides Number using Discrete Geometry, Application to Automatic Pebbles Shape Analysis

We are working in collaboration with geographers to study a set of pebbles digital images. Among the features geographers want to get automatically, pebble sides number is intuitively defined. It is merely computed after a thick polygonalisation of pebble contour. We propose an incremental and linear algorithm, free of restrictive hypothesis, which relies on previous works of Debled et al. (2006). We give some results on synthetical and real images.