Edge and corner preserving smoothing for artistic imaging

What visually distinguishes a painting from a photograph is often the absence of texture and the sharp edges: in many paintings, edges are sharper than in photographic images while textured areas contain less detail. Such artistic effects can be achieved by filters that smooth textured areas while preserving, or enhancing, edges and corners. However, not all edge preserving smoothers are suitable for artistic imaging. This study presents a generalization of the well know Kuwahara filter aimed at obtaining an artistic effect. Theoretical limitations of the Kuwahara filter are discussed and solved by the new nonlinear operator proposed here. Experimental results show that the proposed operator produces painting-like output images and is robust to corruption of the input image such as blurring. Comparison with existing techniques shows situations where traditional edge preserving smoothers that are commonly used for artistic imaging fail while our approach produces good results