View Full Version : FFT Madness Part II


cheg
02-17-2005, 11:32 AM
Hi again

Since I'm obviously too dense to get the whole concept, does anyone have a link to a website which takes you by the hand an leads you itty-bitty step by itty-bitty step through the process? I have but one more day to optimize this photo of one of my work colleague's father who passed away. All I got was a newspaper, so the scan is, well, pixelated as one would expect. I've read the tutes in this forum, I've posted my woes, but there seems to be little tidbits of info missing for me to complete this task succesfully.

Yesterday I posted this
" Ok, found it but...
In Rô's FFT tutorial , he says to make the image grayscale and duplicate the layer. Once that's done, Alex Chirokov's filters are still greyed out. They only appear when I convert the psd file to RGB. What am I doing wrong in this case? Does the image have to be in another format? Jpg? Tiff?"
but no one answered, so I'm hoping there's an in depth tutorial on this filtering process.


Cheers

Alex

kiska
02-17-2005, 11:35 AM
Alex, i wish I could help, but I haven't figured out the !@#$%FFT either.
Sorry.

Swampy
02-17-2005, 11:47 AM
Alex

Your scanner software should be able to be set to print from newsprint and allow for descreening as you scan. I've gotten some crediblel results by playing with the scan software's settings.

cheg
02-17-2005, 11:55 AM
Alex

Your scanner software should be able to be set to print from newsprint and allow for descreening as you scan. I've gotten some crediblel results by playing with the scan software's settings.

I guess I should have mentioned that I had used the descreening function with the scanner software... I want to correct the image at the Photoshop level.

Thanks tho!

MBChamberlain
02-17-2005, 12:04 PM
OK....You need to desaturate the image, not convert it to greyscale. Because the FFT function creates three channels it needs three channels to work with.

1) Duplicate the whole image (right click the bar and select duplicate)
2) Choose Image>Adjustments>Desaturate
3) Run the FFT filter
4) Convert from RGB to HSB
5) On the green channel clone out the stars (not the one in the middle) using lighten as the blend mode (the heal brush set to normal works well too)
6) On the blue channel clone out the stars (not the one in the middle) using darken as the blend mode (or heal)
7) Convert from HSB to RGB
8) Run the IFFT filter
9) If the original was a color image with a pattern you can copy your new image back to the original and set the blend mode to luminosity

If you are doing a news paper scan, you might try scanning it in CMYK, copy each channel to its own file, and run FFT on each, then recombine them.

cheg
02-17-2005, 01:05 PM
You da Man!

Thanks....you provided that one little thing that made all the difference in the world!

Cheers

Alex

T Paul
02-17-2005, 01:18 PM
Love to see a happy ending!

~T

MBChamberlain
02-17-2005, 02:41 PM
glad to help

jonk
02-18-2005, 03:13 PM
Has anyone tried using the FFT filter with Photoshop CS? I keep getting an error when running the FFT filter, and I think the problem is because it was written for PS 7.0.

Jon

vinniesworld
02-18-2005, 04:38 PM
No problem here with CS, it works fine for me.

Caitlin
04-02-2005, 06:19 AM
I've studied a number of posts about this FFT malarky now, but still can't get it to work!

I have a photo with fairly pronounced paper texture, and it sounds like FFT is the thing to use. I've already had a go at the picture with Neat Image, but I did loose a fair amount of detail in the process (and went a bit overboard with unsharp mask to compensate)

If FFT is going to give me a better result I want to give it a go!

I used an RGB image as instructed (though the image is B&W), but when I use the FFT filter in PS7 my R,G,B channels just go completely black!

What am I doing wrong??

I haven't attached a copy of the whole photo as the pattern is too distorted by compression. But I have attached the 'fixed' version, and a sample of the before and after.

ps. I tried the scan it twice at 180degrees thing too without any success. Maybe I'm just having a 'not too bright' day. :dizzy:

Duv
04-02-2005, 09:28 AM
Hi Caitlin

I'm not sure what I did in the past but I had exactly the same thing happen to me. With your image in RGB mode, just run it through the filter. You should be fine. Perhaps with a little experimentation you can get better results than mine.

Dave