A Novel Technique for Opus Vermiculatum Mosaic Rendering
Author(s): S. Battiato, G. Di Blasi, G.M. Farinella, G. Gallo.
Proceedings: 14th International Conference in Central Europe on Computer Graphics, Visualization and Computer Vision (WSCG'06), pp. 133--140, January, 
2006. 
[BibTeX] 

Abstract: 
In this paper we present a method to generate a digital mosaic starting from a raster input image. Mosaics generation of artistic quality is challenging. The basic elements, the tiles, typically small polygons, must be packed  tightly, emphasizing orientations   chosen   by   the   artist.   An adhoc boundaries detection have to be performed  according to the   directional   guidelines. Different mosaic styles can be automatically rendered, depending on artistic techniques considered (“opus musivum”, “opus vermiculatum”, etc.). The proposed method is able to reproduce the colors of the original image emphasizing relevant boundaries by  placing tiles along their direction. The boundaries detection is based on the statistical region merging algorithm. In  particular the technique is able to reproduce the “opus vermiculatum” mosaic style. Several examples reported in the paper show how the right mixture of mathematical tools together with century  proved ideas from mosaicists may lead to impressive results.
 Fast Techniques for Mosaic Rendering
G. Gallo, G. Di Blasi, M. Petralia.
EuroGraphics Workshop on Computational Aesthetics in Graphics, Visualization and Imaging (CA'05), pp. 29--39, Girona, Spain, 18-20 May, 
2005.  [BibTeX]
 Fast Techniques for Non Photorealistic Rendering
G. Di Blasi.
University of Catania, Italy, 
2006.  [BibTeX]