Edge detection operators for angular data

Physical quantities referring to angles, like vector direction, color hue etc., are periodic in nature. Due to this periodicity edge detectors proposed for data on the line cannot be used to detect edges in angle-related signals. In this paper we use estimators of circular dispersion to introduce edge detectors for angular signals and discuss their application in edge detection on hue images. Extensions of the notion of quasi-range to circular data are also proposed. These “circular” quasi-ranges have good and user-controlled properties as edge detectors on noisy angular signals. The performance of the proposed edge operators is evaluated on angular edges, using both qualitative and quantitative criteria