Tracking Targets using Multiple Robots: The Effect of Environment Occlusion

This paper addresses the problem of tracking multiple targets using a network of communicating robots and stationary sensors. We introduce a Region-based Approach which controls robot deployment at two levels. A coarse deployment controller distributes robots across regions using a topological map which maintains urgency estimates for each region, and a target-following controller attempts to maximize the number of tracked targets within a region. A behavior-based system is presented implementing the Region-Based Approach, which is fully distributed and scalable. We compared the Region-based Approach to a ‘naive ’ local-following strategy in three environments with varying degree of occlusion. The experimental results showed that the Region-based Approach performs better than the naive strategy when the environment has significant occlusion. Second, we performed experiments (the environment was held constant) in which two techniques for computing urgency estimates were compared. Last, different combinations of mobile sensors and stationary sensors were compared in a given environment. Keywords: Multi-target tracking, mobile robotics, embedded sensor

A Region-based Approach for Cooperative Multi-Target Tracking in a Structured Environment

This paper addresses the problem of tracking multiple anonymous targets using a network of communicating robots and stationary sensors. We introduce a regionbased approach which controls robot deployment at two levels. A coarse deployment controller distributes robots across regions using a topological map and density estimates, and a target-following controller attempts to maximize the number of tracked targets within a region. A behavior-based system is presented implementing the region-based approach. Intensive simulations were performed to investigate the correlation between our approach and the degree of occlusion in the environment. The region-based approach shows better performance than a `naive' local-following strategy when the environment has significant occlusion. We performed real-robot experiments to validate the system. These experiments open up a new line of research, which suggests that an optimal ratio of robots to stationary sensors may exist for a given environment with certain occlusion characteristics.