.
A Unified Scheme for Adaptive Stroke-based Rendering
Hyung Woo Kang, Charles K. Chui, Uday K. Chakraborty.
The Visual Computer: International Journal of Computer Graphics, Vol. 22, No. 9, pp. 814--824,
2006. [BibTeX]
Coherent Line Drawing
Henry Kang, Seungyong Lee, Charles K. Chui.
5th International Symposium on Non-Photorealistic Animation (NPAR'07),
2007. [BibTeX]
Flow-Based Image Abstraction
Author(s): Henry Kang, Seungyong Lee, Charles K. Chui.
Article: IEEE Transactions on Visualization and Computer Graphics, Vol. 15, No. 1, pp. 62--76,
2009.
[BibTeX] [DOI] 
Abstract:
We present a nonphotorealistic rendering technique that automatically delivers a stylized abstraction of a photograph. Our approach is based on shape/color filtering guided by a vector field that describes the flow of salient features in the image. This flow-based filtering significantly improves the abstraction performance in terms of feature enhancement and stylization. Our method is simple, fast, and easy to implement. Experimental results demonstrate the effectiveness of our method in producing stylistic and feature-enhancing illustrations from photographs.
Interactive Sketch Generation
Hyung Woo Kang, Wenjie He, Charles K. Chui, Uday K. Chakraborty.
13th Pacific Conference on Computer Graphics and Applications (PG'05),
2005. [BibTeX]