Non-photorealistic Rendering of Images as Evolutionary Stained Glass

Non-photorealistic rendering is a broad class of techniques for creating art from digital pictures. One or more digital filters is applied to create an apparent pencil sketch, watercolor, or in this study a design for stained glass. A collection of points that are the centers of weighted Voronoi tilings are evolved to minimize the variance of the variance in luminance within each tile. The average color within each tile is computed. A fractal model of stained glass is then run to create a stained glass texture with a similar average color to that in the tile. Tile boundaries are rendered black, providing the "lead" enclosing the stained glass panes. The stained glass textures are then applied within their corresponding tiles to yield a final image. Evolution of the tile centers is a challenging problem with an expensive fitness evaluation. On the order of 500-3000 real parameters representing the tile centers and their associated weights are optimized. A modified evolution strategy is used to perform this optimization.