Multichannel Image Regularisation Using Anisotropic Geodesic Filtering

This paper extends a recent image-dependent regularisation approach introduced in [Grazzini and Soille, PR09&CCIS09] aiming at edge-preserving smoothing. For that purpose, geodesic distances equipped with a Riemannian metric need to be estimated in local neighbourhoods. By deriving an appropriate metric from the gradient structure tensor, the associated geodesic paths are constrained to follow salient features in images. Following, we design a generalised anisotropic geodesic filter, incorporating not only a measure of the edge strength, like in the original method, but also further directional information about the image structures. The proposed filter is particularly efficient at smoothing heterogeneous areas while preserving relevant structures in multichannel images.