chain83's profile

88 Messages

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1.9K Points

Sat, Jun 23, 2012 5:54 PM

13

Photoshop: FFT-based pattern remover (Filter/Brush/Tool)

A filter that automatically removes/reduces repeating patterns like raster patterns or paper texture.It would be of great help for anyone who ever encounters a scanned image with a repeating pattern (typical for image restoration work or when the only source for an image is a printed copy).Before/after example (click to see gif animation): How to make such a filter: This can be done by doing a Fast Fourier Transform (FFT) to split an image into frequency components. The frequencies that make up repeating patterns will stand out and can be removed (today we do this manually with a black brush, but a filter can remove the "peaks" automatically). And inverse FFT is then performed to transform the image back. This entire process can be automated into one step; perhaps just with a slider to let the user choose how aggressively the filter removes frequencies.I posted a detailed explanation here with a short tutorial on how this is done step by step.Note that this only works on a single channel, so normally you would just bother to do this on the Luminosity component. Filtering each RGB-channel separately can also be done. I will leave that up to you Adobe... ;)

Responses

2 Messages

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102 Points

3 y ago

This reply was created from a merged topic originally titled Photoshop: How about a frequency separation tool or brush?.

I would like to see a frequency separation tool/brush. I know we can use an action to set up frequency separation but wouldn't it be smarter to have a tool that could work on an empty layer without all the extra steps? The tool would have all the adjustments of a normal brush, one form would work on texture and the next would work on color and tone. I would like to hear from a developer if this is even possible.

23 Messages

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520 Points

Uh... That's odd... These are two completely different topics. Why was this merged here?

The only thing in common is the mention of the word "frequency". :P

2 Messages

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92 Points

2 y ago

I'd like to see an FFT feature in PhotoShop as well. Having the preview on a small portion of the image would be super helpful as well when working on very high-res images. 

125 Messages

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2K Points

2 y ago

Steven,
I have a Photoshop script that allows you to run the Ft plugins.  It is located in my GitHub repository.  It has worked on both Win and MAC for versions 6 through 2019 CC of Photoshop.  Let me try to remember how you can get it and the other Ft plugins.
Be back to you soon with a link.

Still have need for MAC help in compiling these things.

RONC

125 Messages

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2K Points

2 y ago

Steven,

Have a download at:  https://www.dropbox.com/s/45mfoxdz1o899r0/RONC_Scripts_Plugins08oct2019.zip?dl=0

This includes the latest Ft plugins and scripts which execute them on Windows with Photoshop CS6 - CC2019.  Readme.txt tells how to install the various pieces.  There are other scripts included which might be of interest.

RONC