Optical character reader with skew recognition
Patent 4941189 Issued on July 10, 1990. Estimated Expiration Date: 
February 13, 2009. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
February 13, 2009. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesMethod and circuit arrangement for formation of features for automatic character recognition OCR Page reader Method for automatic correction of character skew in the acquisition of a text original in the form of digital scan results Patent #: 4723297 InventorAssigneeApplicationNo. 310532 filed on 02/13/1989US Classes:382/290, Where the image is a character, word, or text382/174, Using projections (i.e., shadow or profile of characters)382/177Segmenting individual characters or wordsExaminersPrimary: Boudreau, Leo H.Assistant: Couso, Jose L. Attorney, Agent or FirmInternational ClassG06K 009/32AbstractAn optical character reader (OCR) using parallel state machines is provided wherein each state machine identifies a different character. Program tables for each of the state machines compare received bit strings of scanned data and compare them to positive and negative reference patterns in the state machines, wherein the positive reference patterns are tested for in sequence with advancement of test the next positive reference pattern only if the present positive reference pattern being tested for is present, and if none of at least one negative reference pattern is present. The OCR also detects and corrects skew by mathematically projecting a shadow of each character on the right margin of the page for each of a plurality of small incremental rotation angles for the characters. The rotation angle producing the sharpest and narrowest shadow effect is determined to the angle at which the characters are skewed. | |
