Non-Photorealistic Computer Graphics Library

Using ILIC algorithm for an impressionist effect and stylized virtual environments

Author(s): Chung-Ming Wang, Jiunn-Shyan Lee.
Article: Journal of Visual Languages and Computing, Vol. 14, No. 3, pp. 255--274, June, 2003.
[BibTeX]

Abstract:
Vector fields, often used in science, also find application in the artistic world of sculpture and painting. Apart from color and shape, artists utilize features of direction to depict our natural environment. The line integral convolution (LIC) method, originally developed for imaging vector field in scientific visualization, has the potential to produce images with directional characteristics. In this paper, we present four techniques to explore LIC in generating images in the style of the Impressionists. In particular, we develop an ILIC (Impressionist LIC) algorithm, which takes advantage of the directional information given by a photograph image, incorporates it with a shading technique to blend cool or warm colors into the image, and finally applies the LIC method to imitate artists’ paintings in the Impressionist style. The cool-to-warm blending scheme derives from a painting convention to enhance depth perception. Furthermore, we present a technique using statistical details to control the convolution length for the ILIC algorithm, allowing detailed information to be preserved during the convolution process. We also demonstrate a top-down sampling technique so that a series of mipmaps can be generated to construct virtual environments. These maps, even under multi-resolution viewing, reveal constant strokes, thereby achieving frame coherence in an interactive walkthrough system. The experimental results show satisfactory emulations and efficient computing in fabricating a wide category of artistic virtual environments.