Handwriting Curve Interpolation Using Gradient Graph Laplacian Regularizer

Due to the technical limitation of pen tablets, there are sensing points data loss from the touch screen when the handwriting speed is fast. This problem will cause discrete, segmented, and unsmooth handwriting curves. In order to recover the unknown point coordinates from the observed corrupted curve of handwriting, we propose a curve interpolation algorithm by combining gradient graph Laplacian regularizer and cyclic shift. We first define the gradient of 2D curve and create the related gradient graph. Then the handwriting curve is interpolated by the gradient graph Laplacian regularizer. For handwriting stroke offset, we introduce a cyclic shift of handwriting for translation invariance. Experimental results on synthetic curves and handwriting datasets show that the interpolation quality of our proposed algorithm is better than other competing algorithms, and it promotes the curve smoothness of the turning points.