手绘线矢量化技术的研究与实现

手绘是人类思维外化和表达意图的一种有效方式,如何有效地对手绘线进行矢量化是正确理解绘图者意图的关键。本文提出一种采用组合贝塞尔曲线拟合稠密的二维手绘线数据点列的算法。采用平均弧长对数据点列进行滤波,剔除点列中的冗余点,利用相邻弧长间的夹角及弧长间的比值来估计各弧长中点的离散曲率值,采用平均曲率对各弧长中点进行过滤,识别出手绘线的绝大多数特征点,并分段构造插值于特征点的组合贝塞尔曲线。实验结果表明,所构造的曲线能够很好地反映手绘线的细小特征部分。该算法具有速度较快、拟合精度高等特点,可广泛应用于二维手绘线的矢量化过程。

Investigation and Implementation of Freehand a Vecterization Technology

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.