Constructing task visibility intervals for video surveillance

Vision systems are increasingly being deployed to perform complex surveillance tasks. While improved algorithms are being developed to perform these tasks, it is also important that data suitable for these algorithms be acquired – a non-trivial task in a dynamic and crowded scene viewed by multiple PTZ cameras. In this paper, we describe a real-time multi-camera system that collects images and videos of moving objects in such scenes, subject to task constraints. The system constructs “task visibility intervals” that contain information about what can be sensed in future time intervals. Constructing these intervals requires prediction of future object motion and consideration of several factors such as object occlusion and camera control parameters. Such intervals can also be combined to form multi-task intervals, during which a single camera can collect videos suitable for multiple tasks simultaneously. Experimental results are provided to illustrate the system capabilities in constructing such task visibility intervals, followed by scheduling them using a greedy algorithm.