SYSTEMS, CIRCUITS, AND METHODS FOR EFFICIENT HIERARCHICAL OBJECT RECOGNITION BASED ON CLUSTERED INVARIANT FEATURES

One embodiment is a method for selecting and grouping key points extracted by applying a feature detector on a scene being analyzed. The method includes grouping the extracted key points into clusters that enforce a geometric relation between members of a cluster, scoring and sorting the clusters, identifying and discarding clusters that are comprised of points which represent the background noise of the image, and sub-sampling the remaining clusters to provide a smaller number of key points for the scene.