Abstract:

Freehand is an efficient way for conveying and expressing human ideas. It is the key of how to vectorize the freehand for understanding the drawer’s ideas. A practical algorithm for the combined Bézier curve fitting to a dense data point set of 2DFreehand is proposed. The redundant points are eliminated by using the equalarclength method. The discrete curvature of the arc’s midpoint and the average curvature are calculated. Almost all the feature points are identified by using the equalcurvature method. Finally,a combined Bézier curve is constructed to interpolate all the feature points. A few examples are presented to show that the curve can reconstruct the small features of 2DFreehand well. The algorithm is feasible and efficient, and it can be widely used to deal with the vectorization process of 2DFreehand.

Key words: freehand;vectorization;bézier curve;fitting;discrete curvature;feature point