Image downloaded for Earth Explorer captured by Landsat 7 ETM+
Frequency Domain Editor is a free, open-source application for editing images in their frequency spectrum. It is intended to help visualize the 2D Fourier transform and its effects. You can use it to observe how changes in the frequency domain affect the spatial domain. It is very effective in removing periodic/coherent noise from images. It can also be used to help in frequency domain filter design.