1. An object tracking device for tracking a plurality of objects, the object tracking device comprising: a memory storing a set of instructions; and at least one processor configured to execute the instructions to: store a plurality of candidates for objects to be tracked, each candidate being associated with label information identifying which object the candidate corresponds to, position information, and a likelihood; determine, based on position information of one of the plurality of candidates, one or more other candidates around the candidate; and update a likelihood of the candidate, according to the label information of the determined one or more other candidates around the candidate.