Distributed and decentralized multi-camera tracking: a survey

In recent years the decreasing cost of cameras and advances in miniaturization have favoured the deployment of largescale camera networks. This growing number of cameras enables new signal processing applications that use cooperatively multiple sensors over wide areas. In particular, object tracking is an important step in many applications related to security, traffic monitoring and event recognition. Such applications require the optimal trade-off between accuracy, communication and computing across the network. The costs associated to communication and computing depend on the type and amount of cooperation performed among cameras for information gathering, sharing and processing to validate decisions as well as to rectify (or to reduce) estimation errors and uncertainties. In this survey we discuss data fusion and tracking methods for camera networks and compare their performance. In particular we cover decentralized and distributed trackers and the challenges to be addressed for the design of accurate and energy-efficient algorithms.