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System and method for automated symbolic recognition including spatial reasoning

  • US 7,227,995 B1
  • Filed: 04/18/2003
  • Issued: 06/05/2007
  • Est. Priority Date: 04/18/2003
  • Status: Expired due to Fees
First Claim
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1. A method of automatically recognizing alphanumeric symbols, comprising:

  • (a) receiving digital information indicative of unrecognized alphanumeric symbols;

    (b) computing one or more arcpolys of each unrecognized alphanumeric symbol;

    (c) generating a plurality of candidate lists of alphanumeric symbols;

    (d) generating a reduced list of candidate alphanumeric symbols and confidence levels from the plurality of candidate lists based on one or more symbolic representations of each arcpoly of each unrecognized alphanumeric symbol, wherein the reduced candidate list contains candidates which are common to the plurality of candidate lists;

    (e) determining a best candidate in the list of candidate alphanumeric symbols for each alphanumeric symbol;

    (f) validating the best candidate; and

    (g) if the best candidate cannot be validated, determining alternative sets of reduced candidate lists and repeating (b)-(f) until the alphanumeric symbol is recognized,(h) wherein determining alternative sets of reduced candidate lists involves computing multi-phase symbolic reshaping including a phase comprising;

    criteria-based region growing and splitting of arcpolys so that they better conform to a plurality of alphanumeric symbol models included in a stored candidate list; and

    computing a multi-stage post-processing of arcpolys so that they better conform to a plurality of alphanumeric symbol models; and

    (i) wherein the criteria based growing and splitting comprises;

    computing row-based median and column-based median to derive a threshold used for grouping polyline points into cluster(s) of points;

    detecting significant bends on adjoining lines or detecting significant line size(s) for arcpolys which comprise a (I) line and an arc, or (II) line and a line, and splitting them at a splitting point whereby the two arcpolys best conform to stored alphanumeric symbol models; and

    detecting arcpolys which are significantly more extended than a half circle and splitting them at a splitting point whereby the two arcpolys best conform to stored alphanumeric symbol models.

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