1. A method of tracking closely clustered objects comprising the steps of determining a first set of locations of objects in a cluster according to a coordinate system; assigning object identifiers to each object in the cluster according to its first set location; determining a second set of locations of the objects in the cluster according to the coordinate system, the second set of locations being subsequent in time to the first; assigning object identifiers to each object in the cluster according to its second set location; and correlating the object identifiers in the second set of locations with object identifiers in the first set of locations.