1. A local feature descriptor extracting apparatus comprising: memory that stores an image; a processor configured to: detect feature points in the image; acquire a first local region for each of the feature points; divide each first local region into a first plurality of subregions; generate a first feature vector with a plurality of dimensions for each of the subregions in each first local region; select dimensions from the first feature vector in each subregion such that at least one gradient orientation differs between proximate subregions and output elements of the selected dimensions as a feature descriptor of the first local region; and store, in association with the image, the feature descriptor of each first local region of the image in the memory.