The Simplest 'Hueckel' Edge Detector is a Roberts Operator

Abstract : Hueckel's edge detector finds the best-fitting ideal step edge to a given picture neighborhood, by expanding the neighborhood and step edge in terms of a set of nine basis functions. The simplest case of this approach uses a 2- by-2 neighborhood and three basis functions. This case is solved explicitly using elementary methods. The magnitude of the best-fitting step edge for the neighborhood AB over CD turns out to be the Roberts operator max (abs. val. (A- D), abs. val. (B-C)).