A method for classifying objects in a scene captured by a camera determines a likelihood of first set of states for the objects. Each first set is a classification of one of the objects, and partitions a solution space based on the determined likelihood of the first set of states, each partition representing combinations of the classifications of the objects. The partitioning is applied to a solution space of a second set of states, each partition representing combinations of the classifications of a subset of the objects. The method determines a likelihood of the second set of states for the subset of the objects, each state of the second set of states being a classification of one of the subset of objects, and classifies a subset of objects according to the determined likelihood of the second set of states and the partitioning of the second set of states.