Issue No. 01 - January (1981 vol. 3)
Azriel Rosenfeld , Computer Science Center, University of Maryland, College Park, MD 20742.
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. A very simple case of this approach uses a 2 Ã- 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 CD turns out to be the Roberts operator max (|A - D|, |B - C|).
Azriel Rosenfeld, "The Max Roberts Operator is a Hueckel-Type Edge Detector", IEEE Transactions on Pattern Analysis & Machine Intelligence, vol. 3, no. , pp. 101-103, January 1981, doi:10.1109/TPAMI.1981.4767056