Anisotropic Filtering Controlled by Image Content

The related problems of enhancing and restoring noisy images have received a considerable amount of attention in recent years. Restoration methods have generally been based on minimum mean-squared error operations, such as Wiener filtering or recursive filtering. The rather vague title of enhancement has been given to a wide variety of more or less ad-hoc methods, such as median filtering, which have nonetheless been found useful. In mast cases, however, the aim is the same: an improvement of the subjective quality of the image.