Townsend and Townsend and Crew
Image matching and retrieval by multi-access redundant hashing
 An improved document matching and retrieval system is disclosed where an input document is matched against a database of documents, using a descriptor database which lists descriptors and points to a list of documents containing features from which the descriptor is derived document. The descriptors are selected to be invariant to distortions caused by digitizing the documents or differences between the input document and its match in the document database. An array of accumulators is used to accumulate votes for each document in the document database as the descriptor base is scanned, wherein a vote is added to an accumulator for a document if the document is on the list as having a descriptor which is also found in the input document. The document which accumulates the most votes is returned as the matching document, or the documents with more than a threshold number of votes are returned. 
Ricoh Corporation Ricoh Company, Ltd.
G Y G G
G06V Y10S G06V G06F
inventional additional inventional inventional
Peter E. Jonathan J.
Hart Hull