An object tracking system which includes a plurality of camera devices, each of which captures image data, a plurality of thin-client processors, each of which is connected to a respective camera device via a local connection, each thin-client processor hosting a thin-client application that processes the captured image data to obtain two-dimensional foreground region information by using a background subtraction algorithm, and a server hosting an object tracking application that receives the foreground region information from each thin-client processor via a network and generates a three-dimensional visual hull corresponding to each foreground region represented in the received foreground region information, wherein the object tracking application generates identification and position data corresponding to each three-dimensional visual hull. The thin-client application uses two-dimensional object tracking to identify each object in the foreground region information, and sends each object identity to the object tracking application with the foreground region information.