1. A method for object retrieval and localization, comprising: performing, by one or more computing devices: obtaining an initial ranking of a collection with regard to a query object; generating a ranking of the collection with regard to each of one or more nearest neighbors to the query object as indicated by the initial ranking of the collection; and generating a new ranking of the collection with regard to the query object according to the initial ranking and the generated rankings with regard to each of the one or more nearest neighbors.