Automatic image-based pencil sketch rendering
Author(s): Wang Jin, Bao Hujun, Zhou Weihua, Peng Qunsheng, Xu Yingging.
Article: Journal of Computer Science and Technology, Vol. 17, No. 3, pp. 347--355, May,
2002.
[BibTeX] 
Abstract:
This paper presents an automatic image-based approach for converting grey-scale images to pencil sketches, in which strokes follow the image features. The algorithm first extracts a dense direction field automatically using Logical/Linear operators which embody the drawing mechanism. Next, a reconstruction approach based on a sampling-and-interpolation scheme is introduced to generate stroke paths from the direction field. Finally, pencil strokes are rendered along the specified paths with consideration of image tone and artificial illumination. As an important application, the technique is applied to render portraits from images with little user interaction. The experimental results demonstrate that the approach can automatically achieve compelling pencil sketches from reference images.