The Fourier transform is very useful in dealing with pattern noise, however the way it currently works makes it quite difficult to use on 2018-sized photos - typically 20 to 40 megapixels.
Currently when you run it over an image it produces a long vertical strip. The top part is the useful bit, the other parts are not. A photo 4000x6000 pixels in size ends up being 4000x36000! With 8GB RAM, any subsequent work on this is likely to crash G’MIC, and GIMP operations on it are very slow.
The improvement I suggest is as follows:
- The Fourier transform filter in G’MIC gets an “Only foo” checkbox, where “foo” is the proper name of the top part (what are the names for the top part, and for the noisy rest? “top part” is good enough for me). When enabled, the transformed image contains only the top part - 4000x6000.
- To inversely transform it back into a photo, the filter requires the original layer. When you start the “inverse” transform, it uses the “top part” the user edited, and does a “direct” transform of the original layer for the remaining info, then merges the two to come up with a photo.
Would that be possible?