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Solution for scanned pictures on textured paper

Posted: April 5th, 2010, 12:25 pm
by Dieter Mayr
Hello

Almost everyone who needs to scan printed pictures know about the problem with textured paper, which often pronouncees its texture on the scan.
In a german forum i runned into a link which gives a surprisingly well working solution:
http://commons.wikimedia.org/wiki/Commo ... r_analysis
The neccesary Fourier Transformation is done by a photoshop plugin, the link to it is provided on the linked website.
I have tried the abouve solution, with all steps done in PWP, just for the FFT and IFFT operation i went to PS.
The Plugin runs on my old PS6.
My first try was a actual scan of a B&W-Image:
20696267-1.JPG
20696267-1.JPG (31.9 KiB) Viewed 3996 times
The file was FFT-ed in PS and importet in PWP, then the contrast was enhanced and the bright spots marked in a mask and then using Composite on the original FFT-ed with the Maskand pure Black as overlay:
20696267_fft-1-1.JPG
20696267_fft-1-1.JPG (39.05 KiB) Viewed 3996 times
Then back to PS and IFFT-ed the file give the surprisingly good result:
20696267_1-1.JPG
20696267_1-1.JPG (28.49 KiB) Viewed 3996 times
This method could, to my opinion, be useful to some, so maybe it would be possible one day to implement the FFT and IFFT functions directly to PWP to safe the way around to PS.

Re: Solution for scanned pictures on textured paper

Posted: April 5th, 2010, 12:33 pm
by Dieter Mayr
I also gave the image posted in the above link:
Separation in cannels was done in PWP, converting from 8 bit B&W to 24 bit color, FFT done again in PS, Masking done in PWP as above, IFFT in PS and finally reassembling the channels in PWP.
Before:
Rosa_Gold_Glow_2_with_interference.jpg
Rosa_Gold_Glow_2_with_interference.jpg (48.27 KiB) Viewed 3997 times
After processing:
Rosa_Gold_Glow_2_with_interference_G_1-2-1.JPG
Rosa_Gold_Glow_2_with_interference_G_1-2-1.JPG (43.76 KiB) Viewed 3989 times
Since the image is quiet small so the bright spots are quiet hard to locate, so the result can be improved with a bigger image.

Re: Solution for scanned pictures on textured paper

Posted: April 6th, 2010, 11:43 am
by tomczak
For those wishing to try how useful FFT may be in image processing, you may want to try MeeSoft's Image Analyzer - a freeware.

http://meesoft.logicnet.dk/

Re: Solution for scanned pictures on textured paper

Posted: April 6th, 2010, 5:13 pm
by MikeG
Thanks for the link - interesting site.

Mike.

Re: Solution for scanned pictures on textured paper

Posted: April 7th, 2010, 5:23 am
by MikeG
Here's a link for anyone wishing to know a bit more about Image Analyser:

http://www.retouchpro.com/forums/softwa ... lyzer.html

Mike.