Kim: A curvature estimation for pen input segmentation in sketch-based modeling

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Summary

In this paper the author discusses the techniques for the segmentation of the input through curvature estimation. The features discussed in this paper are direction at a point, support for curvature estimation at Point 'j' and local convexity at Point'j' with respect to P'i'.

Direction at a point for A,B and C is the change in angle formed by the line segments AB & BC. Curvature estimation at point j is the angle from the horizontal of the Line segment AB.
A polygon is locally convexity at Point j with respect to Point i, if the curvature estimation at point j and point i has the same sign.

For segmentation the author uses the local maximum of positive curvature and local minimum of negative curvature at the identified points. These points are then taken as the segmenting points.

The algorithm proposed by Kim produced an accuracy rate of 95% for power point basic shapes and some basic shapes used by other researchers for curvature finding.

Discussion

This paper gives out new feature for curvature estimation for input strokes. Similar features are used by other algorithms for curvature estimation this paper just gives a different approach to the same problem.