Localized edge detection in sensor fields

Abstract

A wireless sensor network that studies relatively widespread phenomena (such as a contaminant flow or a seismic disturbance) may be called upon to provide a description of the boundary of the phenomenon (either a contour or some bounding box). In such cases, it may be necessary for each node to locally determine whether it lies at (or near) the edge of the phenomenon. In this paper, we show that such localized edge detection techniques are non-trivial to design in an arbitrarily deployed sensor network. We define the notion of an edge and develop performance metrics for evaluating localized edge detection algorithms. We propose three different approaches for localized edge detection and present one example scheme for each. In all our approaches, each sensor gathers information from its local neighborhood and determines whether or not it is an edge sensor. We evaluate the performance! of each of the example schemes and compare them with respect to the developed metrics.