Global pose estimation using non-tree models

We propose a novel global pose estimation method to detect body parts of articulated objects in images based on non-tree graph models. There are two kinds of edges defined in the body part relation graph: Strong (tree) edges corresponding to the body plan that can enforce any type of constraint, and weak (non-tree) edges that express exclusion constraints arising from inter-part occlusion and symmetry conditions. We express optimal part localization as a multiple shortest path problem in a set of correlated trellises constructed from the graph model. Strong model edges generate the trellises, while weak model edges prohibit implausible poses by generating exclusion constraints among trellis nodes and edges. The optimization may be expressed as an integer linear program and solved using a novel two-stage relaxation scheme. Experiments show that the proposed method has a high chance of obtaining the globally optimal pose at low computational cost.