1. A method for tracking interacting objects comprising: acquiring, with at least one sensor, at least two images associated with at least two time instances; generating, with at least one processor, image data from the at least two images; applying, with the at least one processor, an extended Probability Occupancy Map (POM) algorithm to the image data to obtain probability of occupancy for a container class of potentially interacting objects, probability of occupancy for a containee class of the potentially interacting objects, and a size relationship of the potentially interacting objects, over a set of discrete locations on a ground plane for each time instance; and estimating, with the at least one processor, trajectories of at least one object belonging to each of the two classes by determining a solution of a tracking model on the basis of the occupancy probabilities and a set of rules describing the interaction between objects of different or the same classes, wherein estimating the trajectories comprises: modeling, with the at least one processor, at least one transition, each transition being between a first one of the at least two images defining a first location with a first orientation of the at least one object, and a second one of the at least two images defining a second location with a second orientation of the at least one object, to produce a flow variable for each transition; modeling, with the at least one processor, a set of rules that describes the interaction between objects of the same or different classes to allow physically-plausible interactions and disallow implausible interactions; defining, with the at least one processor, an objective function in terms of a linear combination of each of the flow variables; and solving, with the at least one processor, the objective function using at least one linear solver.