Aug. 18, 1997 to Aug. 20, 1997
M. Ohta , Grad. Sch. of Eng., Tokyo Univ., Japan
A. Takasu , Grad. Sch. of Eng., Tokyo Univ., Japan
J. Adachi , Grad. Sch. of Eng., Tokyo Univ., Japan
This paper presents three probabilistic text retrieval methods designed to carry out a full-text search of English documents containing OCR errors. By searching for any query term on the premise that there are errors in the recognized text, the methods presented can tolerate such errors, and therefore costly manual post-editing is not required after OCR recognition. In the applied approach, confusion matrices are used to store characters which are likely to be interchanged when a particular character is missrecognized, and the respective probability of each occurrence. Moreover, a 2-gram matrix is used to store probabilities of character connection, i.e., which letter is likely to come after another. Multiple search terms are generated for an input query term by making reference to confusion matrices, after which a full-text search is run for each search term. The validity of retrieved terms is determined based on error-occurrence and character connection probabilities. The performance of these methods is experimentally evaluated by determining retrieval effectiveness, i.e., by calculating recall and precision rates. Results indicate marked improvement in comparison with exact matching.
character recognition; full-text search; text retrieval methods; OCR errors; English-text; missrecognized OCR characters; character connection; input query term; confusion matrices
M. Ohta, A. Takasu, J. Adachi, "Retrieval methods for English-text with missrecognized OCR characters", ICDAR, 1997, 2013 12th International Conference on Document Analysis and Recognition, 2013 12th International Conference on Document Analysis and Recognition 1997, pp. 950, doi:10.1109/ICDAR.1997.620651