FFT Software
© 2017 Mark Hickenbottom
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Setting | "army" photo | "cash" photo | "feathers" photo |
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hardness=80 (instead of 100) | very slightly worse for solid white areas | no significant difference | no significant difference |
brush size=8 (instead of 10) | very slightly worse | noticeably worse on skin and other solid areas of color | slightly worse in certain small areas |
brush size=12 (instead of 10) | very slightly better whites and sunlit neck | just barely better | no significant difference |
using crosses (instead of dots) | much better than dots for texture removal | much better texture removal | noticeably better, especially the face |
marking only central stars (instead of all stars) | a very tiny insignificant change in the pattern noise | a very tiny insignificant change in the pattern noise | a bit worse for background and part of the skin |
![]() before FFT filter | ![]() after FFT filter | ![]() paper deselected, then FFT filter |
![]() using dots | ![]() using crosses |
![]() size 10 dots |
![]() size 6 crosses, various shapes |
Photo | Result | Explanation |
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Army (test 1) | x10 > x8 > x6 >>> d10 > d8 > d6 | Most of the photo was massively improved by covering stars with crosses. However, the sunlit neck and solid white areas (which had no pattern before) developed a faint pattern, especially when using dots. Using crosses of size 10 worked best for these particular areas. |
Army (test 2) | x10=x8=x6 >>> d10 > d8 > d6 | This is a second test of the same photo, but the pattern-free areas that developed a pattern in the first test were deselected before using the fft filter. The sunlit neck and solid white areas were deselected and no longer developed a faint pattern after the fft filter. Crosses of size 6 now worked fine on the entire photo. |
Buddy | x10=x8=x6 > d10=d8=d6 | A cross of any size worked best. |
Cash (test 1) | x10=x8=x6 >>> d10=d8=d6 | Using crosses worked vastly better than using dots for most of the photo. However, solid white pattern-free areas developed a faint pattern, especially when using dots. |
Cash (test 2) | x10=x8=x6 >>> d10=d8=d6 | This is a second test of the same photo, but the solid white areas were deselected before using the fft filter. After using the fft filter, white areas no longer developed a faint pattern. Also, using crosses still worked vastly better than using dots. |
Feathers | x10=x8=x6 >> d10=d8=d6 | Using crosses worked noticeably better than using dots. |
Flower | x10=x8=x6=d10=d8=d6 | Even a small dot worked fine. |
Fur | x10=x8=x6 > d10=d8=d6 | There was a slight difference between using a cross and a dot, and the difference was only in the face. Otherwise, dots worked as well as crosses. |
Picket | x10=x8=x6=d10=d8=d6 | Even a small dot worked fine. |
Poodle | x10=x8=x6 > d10=d8 >> d6 | A cross of any size worked best. |
Snowtree | x10=x8=x6=d10=d8=d6 | Even a small dot worked fine. |
Zorg | x10=x8=x6=d10=d8=d6 | Even a small dot worked fine. |
Test | army | buddy | cash | feather | fur |
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FFT first vs. Reduce Noise first | FFT first much better | about the same | FFT first much better | FFT first slightly better | FFT first slightly better |
FFT first vs. Topaz DeNoise first | FFT first much better | FFT first much better | FFT first much better | FFT first much better | FFT first much better |
1: before Looks horrible. | ![]() |
2: Epson Scan, General descreening Looks better, but dimples are still noticeable on wall, and eyes are a tiny bit blurry. | ![]() |
3: Epson Scan, Newspaper descreening Dimples are much less noticeable, but hair is slightly blurry, eyes and face are slightly blurry, and vertical lines in door trim are lost. | ![]() |
4: Affinity Photo FFT Denoise Easier to see edges of objects (such as vertical lines in door trim), and almost completely free of pattern noise, but plenty of random noise and discoloration left. | ![]() |
5: Affinity Photo FFT + Topaz DeNoise Almost all noise (dimples, texture, discoloration) gone, eyes and trim lines still sharp, but hair is slightly blurry and a few small spots have very faint lines leftover from the pattern noise. | ![]() |
1: before (shown here again for easier before/after image comparison) | ![]() |