Using Entropy to Distinguish Shape Versus Text in Hand-Drawn Diagrams Conference Paper uri icon


  • Most sketch recognition systems are accurate in recognizing either text or shape (graphic) ink strokes, but not both. Distinguishing between shape and text strokes is, therefore, a critical task in recognizing hand-drawn digital ink diagrams that contain text labels and annotations. We have found the 'entropy rate' to be an accurate criterion of classification. We found that the entropy rate is significantly higher for text strokes compared to shape strokes and can serve as a distinguishing factor between the two. Using a single feature - zero-order entropy rate - our system produced a correct classification rate of 92.06% on test data belonging to diagrammatic domain for which the threshold was trained on. It also performed favorably on an unseen domain for which no training examples were supplied.

author list (cited authors)

  • Bhat, A., & Hammond, T.

publication date

  • December 2009