Nonlinear filtering based on a two concentric circular windows operator is introduced as a simple and effective way to find edges in image processing. The dual windows edge detector can operate with no fixed threshold, is isotropic, i.e. its response does not depend on edge orientation and has good noise immunity in the vicinity of edges. Computational requirements are limited and experimental results are good enough.
C. Cafforio, Eugenio Di Sciascio, Cataldo Guaragne