1. P.R. Beaudet, ?Rotationally invariant image operators,? inProc. International Joint Conference on Pattern Recognition, Kyoto, Japan, 1978, pp. 579?583.
2. F. Bergholm, ?Edge focusing,?IEEE Trans. Patt. Anal. Mach. Intell., vol. PAMI 9, pp. 726?741, 1987.
3. F. Bergholm and K. Rohr, ?A comparison between two approaches applied for estimating diffuseness and height of step edges,? Fraunhofer Institute for Information and Data Processing (IITB), Karlsruhe, Germany, House Rep. 10262, 1991; see also Department of Analysis and Computing Science, Royal Institute of Technology, Stockholm, Tech. Rep. TRITA-NA-P9105, CVAP 83, 1991.
4. V. Berzins, ?Accuracy of Laplacian edge detectors,?Comput. Vis., Graph., Image Process., vol. 27, pp. 195?210, 1984.
5. J. Blom, B.M. ter Haar Romeny, and J.J. Koenderink, ?Affine invariant corner detection,? submitted for publication; see also J. Blom, ?Topological and geometrical aspects of image structure,? doctoral dissertation, University of Utrecht, The Netherlands, 1992.