1. A method of compressing a block of image elements, each image element having an associated feature vector, said method comprising the steps of: determining, based on at least a portion of said feature vectors, at 5 least four base vectors with the proviso that if four base vectors are determined, said four base vectors are not positioned in the corners of a right-angled parallelogram in a vector space; defining an order of said at least four base vectors; selecting at least one pair of base vectors of said at least four base 10 vectors as neighboring base vectors according to said defined order; determining, for a selected pair of base vectors, at least one additional vector based on said pair of base vectors; selecting, for at least one image element and based on a feature vector associated with said image element, a vector among said at least four base vectors and said at least one additional vector as a representation of said feature vector; and assigning, to said at least one image element, a vector identifier associated with said selected vector.