The Art of Scale-Space

Artists pictures rarely have photo-realistic detail. Tools to create pictures from digital photographs might, therefore, include methods for removing detail. These tools such as Gaussian and anisotropic diffusion filters and connected-set morphological filters (sieves) remove detail whilst maintaining scale-space causality, in other words new detail is not created using these operators. Non-photorealistic rendering is, therefore, a potential application of these vision techniques. Sieves, in particular, preserve the appropriate edges of retained segments of interest. The resulting image has fewer extrema and is perceptually simpler than the original and is a step towards an artistic nonphotorealistic rendering of the origina. By increasing the amount of simpli- fication towards the margins of the image, the picture composition can be modulated to direct attention to centre of interest of the image. A second artistic goal. The process also removes that detail that provides perceptual cues about texture. This allows the 'eye' to readily accept alternative, artistic, textures introduced to further create an artistic impression. Moreover, the edges bounding segments accurately represent shapes in the original image and so provide a starting point for sketches.