1. A method for selecting and grouping key points extracted by applying a feature detector on a scene being analyzed, the method comprising: grouping the extracted key points into clusters that enforce a geometric relation between members of a cluster; scoring and sorting the clusters based on the density of the key points in the clusters; identifying and discarding clusters that are comprised of key points which represent the background noise of the image based on the densities of the clusters; compressing the key points of the clusters that have not been discarded; communicating these compressed key points over a communications network; searching a reference image database using the compressed key points; identifying at least one cluster that was not discarded based on the searching of the reference image database; communicating the identity of the identified at least one cluster over the communications network; generating feature descriptors from the key points of the identified at least one cluster; and communicating the generated feature descriptors over the communications network.