中文摘要：

目的现有的自然图像素描画效果生成算法存在容易造成画面细节丢失，笔画线条单一等问题。针对这些问题，提出一种改进的自然图像素描画效果生成算法。方法通过模拟艺术家创作素描画过程，采用多层次多尺度方法提取图像中不同层次的细节信息，并使用不同长度不同粗细的笔画来模拟艺术家在创作过程中不同力度的绘画效果，分层绘制画面中不同细节层次，然后融合各层次笔画效果形成最终的素描画笔画效果，最后合并素描画笔画效果和素描画图像底纹。结果通过本文算法，可以得到与原输入自然图像内容一致，色调与艺术家绘制的素描画效果相同，笔画和底纹形式与实际素描画相似，真实感较强的素描画效果输出图像。结论大量实验结果表明，本文算法可以生成高质量的自然图像素描画效果，与现有成熟的铅笔画生成技术相笔，该算法具有较强的可比性。

英文摘要：

Objective Existing algorithms for natural image sketch production easily cause such problems as loss of image details and singleness of stroke line. To solve these problems, this study proposes an improved algorithm for natural image pencil drawing production. Method By simulating the artist creation process of sketch, we adopt a multi-level and muhiscale method to extract details from different image levels. Furthermore, we use strokes of different lengths and thicknesses to simulate the painting effect of different strengths in the process of artist creation, as well as to draw different levels image detail hierarchically. Then, the final sketch stroke effect is obtained by fusing all stroke effect levels. Result We finally merge the sketch stroke effects and image background to obtain the output image, which exhibits content that is consistent with that of the original input image, tonal effect that is the same as an artist＇s drawn sketch, as well as stroke and back-ground form that are similar to those of the actual sketch. The output image has a strong sense of reality in terms of sketch effect. Conclusion A large number of experimental results indicate that the proposed method proposed can generate high-quality natural image pencil drawings. Moreover, the proposed method has strong comparability with the existing mature pencil drawing generation technique.