Apparatus for retrieving data using the remainder of a hashed search key to identify a group of keys and comparing the key to the group of keys

Claim 1

An image storage/retrieval apparatus comprising: first storing means for storing a plurality of images; second storing means for storing a plurality of retrieval data which are assigned image numbers corresponding to said plurality of images, respectively, where each retrieval data comprises a plurality of keywords; third storing means for storing a plurality of keyword numbers corresponding to each of said plurality of keywords, respectively; fourth storing means for storing a plurality of group keywords, where each group keyword corresponds to an image number stored in said second storing means, and where each group keyword is used for specifying groups of keywords obtained by grouping said keywords; primary retrieval means for extracting candidate images from said first storing means using said group keywords, said primary retrieval means comprising: input means for entering at least one retrieval keyword; processing means for reading out from said third storing means a keyword number corresponding to each of said at least one retrieval keywords entered by said input means; means for generating a retrieval group keyword based on said keyword numbers read by said processing means, wherein said generating means classifies said keywords into one of said group keywords using units which correspond to remainder values obtained when said keyword numbers are divided by a predetermined bit count, said group keywords having numbers which are each represented by a byte count; first image number extracting means for sequentially comparing said plurality of group keywords stored in said fourth storing means with said retrieval group keyword generated by said generating means, and for extracting an image number having a group keyword which is the same as the retrieval group keyword generated by said generating means; and second image number extracting means for sequentially comparing said keyword numbers stored in said third storing means and corresponding to said image number extracted by said first image number extracting means with said at least one retrieval keyword entered by said input means, and for extracting an image number having a keyword coinciding with each of said at least one input retrieval keywords as a candidate image; and secondary retrieval means for retrieving a predetermined image, said secondary retrieval means comprising selecting means for selecting a desired image from said candidate images extracted by said second image number extracting means, and means for retrieving said image selected by said selecting means from said first storing means.