MOD
gerry.m 6:17pm, 29 July 2007
Four months ago Harry Limey referred to a Fourier transform technique for removal of repeating patterns.
www.flickr.com/groups/90604013@N00/discuss/72157600010402...
"I used the Fourier transform technique described here, supposed to be specifically designed for this type of moire effect!
retouchpro.com/tutorials/?m=show&id=185
There is another far more complicated method that can be tried using the three coloured channels, but I had difficulty with that!!"

I went hunting for, and found the Photoshop plug-in written by Alexandre V. Chirokov. At this time the plug-in, Fourier Transform Plug-in by A.V. Chirokov, is a freeware download at www.4N6site.com.

The following is a comparison showing a photo of myself from 1959 with the repaired copy. As was common, it was printed on a patterned paper. The mag view shows the pattern. You can also see it looking at the full size images.
Gerry 1959 school photo repair compare
Gerry 1959 school photo repair mag compare
The plug-in is easy to use. I don't happen to use it with Photoshop at this time. Right now I use Corel Photopaint and the plug-in worked fine.

You apply the plug-in to an RGB color image. The output is the image below.
Gerry 1958 FFT repair 1
At this point you separate the image into the RGB color channels. You now work with the red channel which has amplitude information. For my photo the red channel looked as shown.
Gerry 1958 FFT RGB split red repair 2
You then use a cloning tool to remove all bright points outside the center one. For my photo that image follows. This was a fast removal. I see I missed a few bright dots in the cloning process for this example. :>)
Gerry 1958 FFT RGB split red repair 3
Once done you just recombine the RGB channels. The resulting image looks very similar to what you started with. At this point you apply the reverse plug-in to get your image back, and the pattern is gone, but image detail is maintained. I'm very impressed. It really does work.

The final photo had only two small defects repaired after the plug-in (I couldn't resist). The mag view above shows a minimal residual of the pattern along the hair-background line. There is a slight banding at the top of the photo which is easily correctable. I did not correct for this example however.
Gerry 1959 school photo repair

I recommend this plug-in. It's impressive in its function and very easy to use.
--Gerry
admin
Robert Silverwood 11 years ago
Gerry, that is very impressive. I'm off to look at this right away. To remove this type of pattern is tedious at best and nearly impossible when it's over another pattern in the image (such as the checked shirt).
MOD
gerry.m Posted 11 years ago. Edited by gerry.m (moderator) 11 years ago
One thing to keep in mind is that this deals with amplitude only so the output is black and white. I saw one example where the color was "put back" after. I don't understand that aspect of the process yet.

The original comment by Harry gave a reference which used a color image as an example. Since I don't use Photoshop currently, I didn't understand how to put the color back in. Take a look at that example also.
retouchpro.com/tutorials/?m=show&id=185
--Gerry
admin
Robert Silverwood 11 years ago
Gerry, this is an extraordinary plugin (especially for a freebie)

I 'jumped straight in at the deep end' by trying it out on this photo which I remembered seeing in this group a few months ago. The problem comes from it being scanned from a magazine type publication rather than the texture of the paper, so it could be useful for that as well.

The larger view or the enlargement is needed to see the before and after clearly.

Don't worry about the colour technique, it's very simple. On this example, all the colour comes from the original patterned image - not from me 'painting' it in.

As usual, I used my old faithful Paint Shop Pro which handles the 8bf plugins just fine.

Moire pattern problem

Moire pattern problem closeup
pollyhyper 11 years ago
Wow, I'm really anxious to try this. I have a photo I've been holding off on working (because it was driving me nuts) that's printed on this lovely, old textured paper. Lovely, that is, until you try to scan it in!
Thanks so much!
MOD
gerry.m 11 years ago
Robert,
Could you give me a little more detail on putting the color back in. It's not clicking for me?
--Gerry
admin
Robert Silverwood 11 years ago
Sure Gerry,
It's similar to my two layer method of colouring vintage photos. On the top layer put the freshly made b&w image from the FFT process. On the bottom layer place a colour copy of the original photo. Set the blend mode of the top (b&w) layer to "Luminance". Select the bottom (colour) layer and apply a slight blur to "smudge out" the pattern but leave the colour in patches. The original tutorial suggested a Median filter for this but I got better results in PSP using a Gaussian blur - adjust the amount until the pattern just disappears. That's about it really, just merge the two layers or export a merged copy if you want to keep the layers in your working file.

Hope that helps, just ask again if it's still not 'clicking'
magpie-moon 11 years ago
Robert, this is an awesome correction! I'm amazed at how much better it's turned out. This is greatly appreciated since I wasn't able to get the book back to try scanning again.

I'm going to get that plugin and try it on another photo of Marina at age 5 that was on a textured paper and gives a different kind of pattern when scanned.

Thanks so much for remembering and for doing this.

-- Marina's Mom
manitou2121 11 years ago
I always used a black brush on the dots because of this post on ReouchPro by the FFT expert jcr6 of ReindeerGraphics.com:
I must really strongly urge using a black brush with solid black in the middle of it instead of gray and especially instead of cloning. Otherwise a small amount of the pattern will remain.

However, your results on these images seem better than mine, so I will try the clone brush on darken mode.

jcr6 had another tip worth considering:
1) If you increase the canvas size, filling with gray, by at least 100 pixels on both dimensions before doing the FFT (and doing a new crop afterwards) you can solve the "ringing at the edges" of your image. The provides some padding and cuts in half the amplitude of the step from the top to the bottom. It would be even better to fill that in with the Average of the image, but 128 gray is sufficient.
(By 128, he means 50%.)
Marc Lambrechts 11 years ago
Thanks Gerry for sharing this technique with us.

I have a few of these photos that I did not scanned as I did not like the result. I tried the technique quickly on a sample, it worked well!

Time to get these old pictures out and start scanning ...
Marc Lambrechts 11 years ago
No time lost and I used this 1974 family picture for a full resolution trial.

Before........................................................................ After

1974 jan met leeuw - before and after FFT clean-up - detail

The full picture - check at original size :

1974 jan met leeuw - before and after FFT clean-up

Very 1974 colors by the way ;-)
Rob Gillespie Posted 11 years ago. Edited by Rob Gillespie (member) 11 years ago
This is the best plugin I've seen. Phenomenal stuff. I put the colour back in by following the above advice, except that I didn't need to 'paint' anything out. I simply put the original colour image in a layer underneath the b&w fixed version, changed the mode the luminosity and everything looked fine.
prickly control [deleted] 11 years ago
Wow! I didn't even know there was such a thing! Awesome.
Chris Hernandez 10 years ago
so does this plugin really NOT WORK on a mac? I use it on XP and it works fine, although my photoshop is only utilizing 1.6GB of ram out of my 4GB, and it crashes on large images. Has anybody tried this on a Mac?
admin
ericdege 10 years ago
I haven't seen a free Mac version of the Fourier Transform Technique Plug-in ..Reindeer Graphics does offer it as part of their Image Processing Toolkit however ..Version 5 and later are Mac OS compatible and cost about $249 (US)
..A discussion on one of the Adobe Forums (from September/October 2008) suggests that there isn't a Mac version other than the one from Reindeer Graphics
Mishu97 7 years ago
Hi,

I am having some trouble getting the plugin to show up in CS5 (64-bit). Is this only a 32-bit plugin?

Am I out of luck here?

Thanks,
unimatrix001 Posted 7 years ago. Edited by unimatrix001 (member) 7 years ago
There is a small program called image j that is written in java and runs on any platform. it is a stand alone program. it can be downloaded from here. There are both 32 and 64 bit versions of the program.

rsbweb.nih.gov/ij/download.html

The Fourier Transform plugin, i have use a couple of times but find sometimes it doesnt work and is hard to set up in the photoshop arena
I did find an action that removes most of the work down to the removal of the pattern. it has instructions in the action to let you know what to do and how to fix things ... This i use all the time and seems to run very well. the action can be downloaded from this site. there is one there that they say is new but not sure how new it is ...

www.skeller.ch/ps/fft_action.php
from what i can see download the fft action not the new one. download the filters and place them in the cs5 plugin folder,. tried the new action but couldnt find the filters for them. there is also an fft brush you can download.
4N6site 6 years ago
Excellent demonstrations of the Fourier transform plug-in, and great results. I'd like to use some of them for the 4N6site.com website.
Currently the website is aimed at forensic scientists but the plug-ins are at least as useful in photo restoration and retouching: removal of stains, ink, discolorations (color deconvolution plug-in), perspective and warping (warping plug-in), and of course the repeating patterns (Fourier transform plug-in). I'd like the website to be aimed more at photorestoration so I messaged some posters to ask for their permission to use some of these examples.
The Fourier transform is Win only and works with 32 bit plug-in hosts. That means it works in 32 bit Photoshop regardless of whether your Windows is 32 or 64 bits.
I would like to post an example of color deconvolution e.g. to remove ballpoint ink lines from a photograph, but it is more fun if someone actually has a problem with such lines or any stains on a photo and wants me to give it a shot...
Same for silvering/mirroring, let me know if you have such an image and I will work on it!
Mishu97 6 years ago
Thanks for mentioning the ImageJ unimatrix001....it solved my problem! :)
Groups Beta