Abstract: Disclosed are a document retrieval method and system for separately performing a process for correcting erroneously recognized characters existing in characteristic character strings within a seed document or the documents to be registered and a process for tolerating erroneously recognized characters existing in the documents targeted for retrieval. The process for correcting erroneously recognized characters existing in characteristic character strings extracts characteristic character strings from a read document, replaces the extracted characteristic character strings containing erroneously recognized characters with character strings appropriate for document retrieval, and selects characteristic character strings for use in actual document retrieval.

Abstract: An apparatus for expanding a character string. The character string that is entered to search includes a character string dividing device to divide the entered character string into partial character strings. A referencing device is provided to reference a similarity table. The similarity table stores in advance similar partial character strings, each of the similar partial character strings being derived from each of the partial character strings by changing at least one of the characters of each string to a different character which is similar in shape. An expansion device is provided to combine similar partial character strings into expanded words and store them in table.

Abstract: Disclosed are a document retrieval method and system for separately performing a process for correcting erroneously recognized characters existing in characteristic character strings within a seed document or the documents to be registered and a process for tolerating erroneously recognized characters existing in the documents targeted for retrieval. The process for correcting erroneously recognized characters existing in characteristic character strings extracts characteristic character strings from a read document, replaces the extracted characteristic character strings containing erroneously recognized characters with character strings appropriate for document retrieval, and selects characteristic character strings for use in actual document retrieval.

Abstract: An apparatus for expanding a character string, which character string is entered to search includes a character string dividing device to divide the entered character string into partial character strings a referencing device to reference a similarity table, the similarity table storing in advance similar partial character strings, each of similar partial character strings being derived from each of the partial character strings by changing at least one of the characters of each string to a different character which is similar in shape, and an expansion device to combine similar partial character strings into expanded words and store them in table.