Source: http://www.google.com/patents/US5031225?ie=ISO-8859-1
Timestamp: 2014-12-26 05:16:54
Document Index: 325882334

Matched Legal Cases: ['art 14', 'art 14', 'art 17', 'art 19', 'art 20', 'art 22', 'art 23', 'art 17']

Patent US5031225 - Character recognition method for recognizing character in an arbitrary ... - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsA character recognition method includes reading a document having characters displayed thereon and entering a document data representative of the content of the document. Image data of one of the characters from the document data is extracted. The one character has an orientation rotated by an arbitrary...http://www.google.com/patents/US5031225?utm_source=gb-gplus-sharePatent US5031225 - Character recognition method for recognizing character in an arbitrary rotation positionAdvanced Patent SearchPublication numberUS5031225 APublication typeGrantApplication numberUS 07/281,728Publication dateJul 9, 1991Filing dateDec 9, 1988Priority dateDec 9, 1987Fee statusLapsedPublication number07281728, 281728, US 5031225 A, US 5031225A, US-A-5031225, US5031225 A, US5031225AInventorsMichiyoshi Tachikawa, Masayuki Ishigami, Hiroyoshi Ishizaki, Hiroshi NakayamaOriginal AssigneeRicoh Company, Ltd.Export CitationBiBTeX, EndNote, RefManPatent Citations (3), Referenced by (43), Classifications (7), Legal Events (6) External Links: USPTO, USPTO Assignment, EspacenetCharacter recognition method for recognizing character in an arbitrary rotation positionUS 5031225 AAbstract A character recognition method includes reading a document having characters displayed thereon and entering a document data representative of the content of the document. Image data of one of the characters from the document data is extracted. The one character has an orientation rotated by an arbitrary rotation angle from a predefined reference position for the one character. A first feature quantity of the one character is extracted from the extracted image data. The extracted feature quantity is converted into a second feature quantity of the one character in the reference position based on the arbitrary rotation angle. A dictionary which contains stored feature quantities of a plurality of characters in the reference position is interrogated so as to find a primary candidate character which has a feature quantity matching or most closely resembling the converted feature quantity.
What is claimed is 1. A character recognition method comprising steps of:reading a document having characters displayed thereon and entering document data representative of the content of the document; extracting image data representative of one of the characters from the document data, said one character having an orientation rotated by an arbitrary rotation angle from a predefined reference position for said one character; extracting a first feature quantity of said one character; converting the extracted feature quantity into a second feature quantity of said one character in the reference position based on said arbitrary rotation angle; referring to a dictionary which contains stored feature quantities of a plurality of characters in the reference position so as to find a primary candidate character which has a feature quantity matching or most closely resembling the second feature quantity; and selecting said primary candidate character as said one character. 2. A character recognition method as claimed in claim 1 in which said step of converting the first feature quantity into the second feature quantity carries out a conversion dependent on a convention formula related to the relationship between the first feature quantity and the second feature quantity.
18. A character recognition method comprising steps of:reading an original document having characters displayed thereon; storing document data representative of the character content of the document; extracting image data representative of one of said characters from said document data, said one character having a first orientation; extracting a firs feature quantity of said one character from said image data; converting said first feature quantity into a second feature quantity based on a predetermined relationship between said first orientation and a second predefined orientation for said one character that is different from said first orientation; referring to a dictionary which stores feature quantities of a plurality of characters in said second orientation so as to fund a primary candidate character that has a feature quantity matching or closely resembling said second feature quantity; and selecting said primary candidate character as said one character. 19. A character recognition method as claimed in claim 18, wherein said predetermined relationship is a rotation angle indicative of the relative difference between said one character in said first and second orientations.
BACKGROUND OF THE INVENTION The present invention generally relates to character recognition methods, and more particularly to a character recognition method for recognizing a character even when the character is rotated by an arbitrary angle from a regular position.
SUMMARY OF THE INVENTION Accordingly, it is a general object of the present invention to provide a novel and useful character recognition method in which the problems described above are eliminated.
BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A and 1B respectively show document images in which characters are written along certain directions;
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 3 shows a character recognition apparatus for explaining embodiments of the character recognition method according to the present invention. The character recognition apparatus has a scanner 10, an optical character recognition (OCR) apparatus 11 indicated by a one-dot chain line, and an OCR controller 12 made up of a display unit 12a and a keyboard 12b. The OCR apparatus 11 has an OCR master 13, a recognition part 14 indicated by a phantom line, and a rotation information register 15. The recognition part 14 has a pre-processor 16, a feature extraction part 17, a histogram generator 18, a conversion part 19, a conversion information generating part 20, a dictionary 21, a matching part 22, and a result output part 23.
Next, a description will be given of a second embodiment of the character recognition method according to the present invention According to this embodiment, the feature extraction part 17 assigns the direction codes to the contour picture elements of the character pattern in a manner similiar to the first embodiment, but in the second embodiment, the character pattern is divided into a plurality of adjacent regions arranged in an array and a histogram of the direction codes is obtained for each of the divided regions. For convenience sake, it will be assumed that the character pattern is divided into 16 adjacent regions arranged in a 4�4 array.
N=4�]3-MOD(n-1, 4)[+(n-1)/4+1                        (2)
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22, 2003REMIMaintenance fee reminder mailedJan 4, 1999FPAYFee paymentYear of fee payment: 8Dec 28, 1994FPAYFee paymentYear of fee payment: 4Feb 16, 1989ASAssignmentOwner name: RICOH COMPANY, LTD., A JAPANESE CORP., JAPANFree format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:TACHIKAWA, MICHIYOSHI;ISHIGAMI, MASAYUKI;ISHIZAKI, HIROYOSHI;AND OTHERS;REEL/FRAME:005038/0150Effective date: 19890120RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google