Abstract-In this work we study the problem of real-time optimal distributed partitioning for perimeter patrolling in the context of multi-camera networks for surveillance. The objective is to partition a line of fixed length into non-overlapping segments, each assigned to a different camera to patrol. Each camera has both physical mobility range and limited speed, and it must patrol its assigned segment by sweeping it back and forth at maximum speed. Here we propose three different distributed control strategies to determine the extremes of the patrolling areas of each camera. All these strategies require only local communication with the neighboring cameras but adopt different communication schemes: synchronous, asynchronous symmetric gossip and asynchronous asymmetric gossip. For the first two schemes we provide theoretical convergence guarantees, while for the last scheme we provide numerical simulations showing the effectiveness of the proposed solution. I. INTRODUCTION Current and future generations of video-surveillance systems target large scale scenarios where tens or even hundreds of smart Pan-Tilt-Zoom (PTZ) cameras coordinate one another to monitor the environment, cooperate so as to detect and track events, and perform high level decision tasks, through video content analysis algorithms. To this aim, cameras appear as actuated sensor nodes embedded in the installation environment and connected through a communication network. Trading-off between the complexity of the installation and the coverage performance, one canonical task of such systems is that of patrolling, meaning the act of walking around an area in order to protect or supervise it [1]. In this sense, a good patrolling strategy is one that minimizes the time lag between two visits to the same location, thus ensuring that all locations are constantly monitored. In particular, there exists an interesting variety of outdoor video-surveillance scenarios where this task takes the structure of perimeter patrolling, in which the patrolling action is limited to the one dimensional boundary of the area to be protected. To briefly review the literature, we start by pointing out how the problem of patrolling shows analogies with the problem of dynamic optimal coverage in sensor networks, as in [8] , [9] where a team of mobile agents needs to coordinate to attain distributed coverage of an area while avoiding collisions. Similarly, considering coordinated robotic systems,
In REF , the authors use a similar technique to coordinate a team of video-cameras in surveillance missions.
Distributed partitioning strategies for perimeter patrolling
Proceedings of the 2011 American Control Conference
Proceedings of the 2011 American Control Conference
Computer Science