Abstract
Three new topological quantities are proposed in order to be used in combination with the Euler number in shape classification procedures. These quantities are evaluated using the convex deficiency of the shape as well as orientation depended variations of its convex hull. The proposed topological feature vector is prone to problems or instabilities imposed by the rectangular grid. The computational load is related to the time needed for convex hull and Euler number evaluation. Its classification results are satisfactory when it is used in separating typewritten letters or a small number of binary silhouettes.