A plugin-filter that smoothens an image with periodic boundary conditions.
The filter is intended for smoothing in the Fourier domain, e.g. for smoothing custom FFT filters, and for rotational smoothing when used after the Polar_Transformer plugin.
“Periodic boundary conditions” means that the image is treated as if repeated on all sides. Thus, an object at, e.g., the right edge of the image will be blurred into the image at its left edge.