“…Much of the earlier research focus in motion analysis has been on high-level object trajectory representation schemes that are able to produce compressed forms of motion data (Aghbari et al, 2003;Chang et al, 1998;Dagtas et al, 2000;Hsu & Teng, 2002;Jin & Mokhtarian, 2004;Khalid & Naftel, 2005;Shim & Chang, 2004). This work presupposes the existence of some low-level visual tracking scheme for reliably extracting object-based trajectories (Hu, Tan, Wang & Maybank, 2004;Vlachos et al, 2002).…”