Coarse-to-fine global localization for mobile robots with hybrid maps of objects and spatial layouts

This paper proposes a novel global localization approach that uses hybrid maps of objects and spatial layouts. We model indoor environments using the following visual cues from a stereo camera: local invariant features for object recognition and their 3D positions for object location representation. We also use a 2D laser range finder. Therefore, we can build a hybrid local node for a topological map that is composed of an object location map and a spatial layout map. Based on this modeling, we suggest a coarse-to-fine strategy for the global localization. The coarse pose is obtained by means of object recognition and point cloud fitting, and then its fine pose is estimated with a probabilistic scan matching algorithm. With real experiments, we show that our proposed method can be an effective global localization algorithm.