1. A method of filtering an image dataset, having the following steps: providing an N-dimensional input image dataset; applying a filtering algorithm to the input image dataset, wherein the filtering algorithm is essentially unvarying over the dataset, to thereby obtain a filtered image dataset; wherein this step may be repeated with different filtering algorithms to thereby obtain further filtered image datasets; providing a pre-determined spatially varying weighting function between the input and the at least one filtered image dataset; computing a weighted sum of the input image dataset and the at least one filtered image dataset, thereby using the spatially varying weighting function, in order to obtain an output image dataset.