Approximate Initialization of Camera Sensor Networks

Camera sensor networks—wireless networks of low-power imaging sensors—have become popular recently for monitoring applications. In this paper, we argue that traditional vision-based techniques for calibrating cameras are not directly suitable for low-power sensors deployed in remote locations. We propose approximate techniques to determine the relative locations and orientations of camera sensors without any use of landmarks or positioning technologies. Our techniques determine the degree and range of overlap for each camera and show this information can be exploited for duty cycling and triggered wakeups. We implement our techniques on a Mote testbed and conduct a detailed experimental evaluation. Our results show that our approximate techniques can estimate the degree and region of overlaps to within 10% of their actual values and this error is tolerable at the application-level for effective duty-cycling and wakeups.