A new nonlinear technology for edge detection was presented.The algorithm performs a preliminary selection of edges using a standard Sobel bradient operator and uses a two-concentric-circular-window operator to reveal real edges within a set of edge candidates.By comparisons with other well-established technologies for edge detection,the results show that the nonlinear algorithm is better than stadard Sobel operator in terms of visual appearance of edges,and that detected edges are surely comparable with Canny and LoG algorithms,with lower computational load.