×

Line extraction in digital ink

  • US 7,526,128 B2
  • Filed: 02/17/2004
  • Issued: 04/28/2009
  • Est. Priority Date: 02/26/2003
  • Status: Expired due to Fees
First Claim
Patent Images

1. A searchable electronic filing system including:

  • (a) a first database for storing a digital representation of each of a plurality of printed documents, each printed document including machine-readable identification data which distinguishes it from the others;

    (b) a second database for storing annotation digital ink, the annotation digital ink representing at least one physical handwritten annotation on at least one of the printed documents;

    (c) a processor configured to;

    i. segment the annotation digital ink into lines by;

    obtaining a stroke sequence comprised of a sequence of strokes;

    removing small strokes less than a threshold length;

    segmenting the strokes into a sequence of substrokes by;

    computing a relative angle for each line segment connecting successive stroke data points; and

    segmenting the stroke into substrokes if the difference between successive relative angles is greater than a preset threshold; and

    identifying the substrokes at line breaks, thereby facilitating line extraction, by;

    computing N-neighbourhood centroids;

    computing angular differences between N-neighbouring substrokes, or groups of substrokes; and

    computing local maxima of the angular differences in the sequence of substrokes;

    ii. accept a digital ink query;

    iii. match the digital ink query against at least some of the annotation digital ink in the second database, to thereby identify a corresponding one of the documents in the first database.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×