A high precision operator to determine edge orientation

This paper studies the principles underlying the design of gradient masks. Their behavior is studied with particular reference to accurate estimation of angular edge orientation. An operator based on two pairs of gradient masks is obtained in this way. The first pair of gradient masks used are the classic Sobel masks. Since the precision of Sobel operator is not high enough for some concrete orientations, a second pair of gradient masks is introduced in this paper. These two pairs of gradient masks allow to determine edge orientation of edges, with a higher precision than classical operators, whatever their orientation in the image is