Abstract: A method for searching for a digital image representing a graphical pattern generates the descriptor of an image as a 2D m×n matrix (m, n: whole numbers): resample digital image to produce normalized image of dimensions c.m×d.n (c, d: given whole numbers), process the normalized image in p processes, indexed 1-p (p: given whole number), producing p digital characteristic images (CI), each having m×n sub-images (SI), each S-I being c×d, each CI is reduced to m×n by replacing each SI by at least one representative value determined as a function of the c×d SI pixels, a selection function selects from p values, at least one value as selected value, each descriptor element (i, j), i?[l,m], j?[l,n] is allocated the processing index from which the CI is derived generating the reduced image including the selected value from the selection function applied to p pixels (i, j) of the P reduced images.