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Recognition method for letter patterns

  • US 4,987,603 A
  • Filed: 09/22/1988
  • Issued: 01/22/1991
  • Est. Priority Date: 09/22/1988
  • Status: Expired due to Term
First Claim
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1. A letter pattern recognition method comprising the steps of:

  • preprocessing character patterns;

    extracting characteristic data for the character patterns according to elements including a loop, a straight line and an arc which have branches and nodes;

    obtaining a center of gravity for each of the respective elements;

    normalizing the character patterns by using the extracted characteristic data;

    comparing the normalized character patterns with pre-registered classification codes by allotting relative positions of the loop, straight line and arc elements in accordance with information on the center of gravity thereof and determining if a return check is required depending upon the result of the comparison, and performing a return check and returning to the extracting step if a return check is required;

    performing balance and stroke checking for the normalized patterns in the absence of the requirement for the return check, wherein the balance checking is performed by using a relationship of weight on the relative position and wherein the stroke checking is performed by checking a direction of the straight line elements, a rotational direction of the arc elements and a link structure of the elements; and

    detail-classifying the normalized patterns in such a manner that an orientation of the arc elements, and a length ratio of the elements so as to thereby recognize the character patterns.

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