Resource-Aware Coverage and Task Assignment in Visual Sensor Networks

A visual sensor network (VSN) consists of a large amount of camera nodes which are able to process the captured image data locally and to extract the relevant information. The tight resource limitations in these networks of embedded sensors and processors represent a major challenge for the application development. In this paper, we focus on finding optimal VSN configurations which are basically given by: 1) the selection of cameras to sufficiently monitor the area of interest; 2) the setting of the cameras´ frame rate and resolution to fulfill the quality of service requirements; and 3) the assignment of processing tasks to cameras to achieve all required monitoring activities. We formally specify this configuration problem and describe an efficient approximation method based on an evolutionary algorithm. We analyze our approximation method on three different scenarios and compare the predicted results with measurements on real implementations on a VSN platform. We finally combine our approximation method with an expectation-maximization algorithm for optimizing the coverage and resource allocation in VSN with pan-tilt-zoom camera nodes.