6. A pattern recognition apparatus according to claim 1 , wherein: the comparing section makes comparisons of the query feature with the reference features that are related to the corresponding reference patterns and stored in a hash table, wherein: the hash table has a plurality of bins; each reference feature is preliminarily classified and stored in one of the bins determined through a calculation of a predetermined hash function from the reference feature; and the comparing section refers an appropriate bin for each comparison using an index that is obtained through a calculation of the hash function from the acquired query feature.
6. A pattern recognition apparatus according to claim 1 , wherein: the comparing section makes comparisons of the query feature with the reference features that are related to the corresponding reference patterns and stored in a hash table, wherein: the hash table has a plurality of bins; each reference feature is preliminarily classified and stored in one of the bins determined through a calculation of a predetermined hash function from the reference feature; and the comparing section refers an appropriate bin for each comparison using an index that is obtained through a calculation of the hash function from the acquired query feature. 7. A pattern recognition apparatus according to claim 6 , wherein: each reference feature is stored in the bin with related to coordinate data of the acquired three feature points and to an identifier of the reference pattern corresponding to the reference feature; and the pattern determination section estimates a pose of the query image based on matching of each coordinate data related to the query feature to that related to each reference feature stored in the referred bin and based on a majority rule on the matching.