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. It is shown that certain scale-space filters preserve the appropriate edges of retained segments of interest. The resulting images have fewer extrema and are perceptually simpler than the original. A second artistic goal is to accentuate the centre of attention by reducing detail away from the centre. The process also removes the detail providing perceptual cues about photographic 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.