Simple Nonlinear Dual Window Operator for Edge Detection

We propose a nonlinear edge detection technique based on a two concentric circular windows operator. We perform a preliminary selection of edge candidates using standard gradient and use the dual window operator to reveal edges as zero-crossing points of a simple difference function only depending on the minimum and maximum values in the two windows. Comparisons with other well-established techniques are reported in terms of visual appearance and computational efficiency. They show that detected edges are surely comparable with Canny's and Laplacian of Gaussian algorithms, with a noteworthy reduction in terms of computational load.