Original image

Filter applied

Regularize geometry at a speed proportional to the local mean curvature value: this filter uses the mean curvature algorithm to blur the image preserving edges.

The Mean Curvature algorithm is described on Wikipedia.

This filter is found in the main menu under Filters → Blur → Mean Curvature Blur….

Original image

Iterations = 4

Mean Curvature Blur can be used to denoise an image:

Original image

Iterations = 9