Fast Fourier Transform (FFT)

[mustang]

Anyone have experience w/FFT? Does it work w/PSE?

[Ellen]

I don't but am curious about it. Try here.
http://www.retouchpro.com/forums/search.php?searchid=424657
It makes my head spin and I don't know how much translates to Elements

[Daviskw]

Hi there

HERE (http://meesoft.logicnet.dk/) is a free stand-alone program that does the job as good as any on the net... at least that I have used.

It will remove paper texture better than most.

Butch

[Daviskw]

Below is an example of Image Analizer removing paper texture. Look particularly between the hair and face.

I am just talking about the pattern not the color. It does a very good job with minimal blurring.

Butch


http://www.pixentral.com/hosted/1s7uHQZOHRVncJV5GfCkoFdLgJmbY70_thumb.jpg (http://www.pixentral.com/show.php?picture=1s7uHQZOHRVncJV5GfCkoFdLgJmbY70)

[Daviskw]

Open Image Analyzer and under Filters in the main menu you will find the "Frequency domain filter"

It takes it a few minutes to load depending on the size and resolution of your picture but the filter window will appear as below.

All you do is pick a pen size and blacken the center of each star. Just be sure not to touch the main star in the upper center.

All there is to it.

Butch


http://www.pixentral.com/hosted/1Ly4P4MDkZd0E6Jwx80Xzqu1kVTwI1_thumb.jpg (http://www.pixentral.com/show.php?picture=1Ly4P4MDkZd0E6Jwx80Xzqu1kVTwI1)

[mustang]

Thanks for the info. Have downloaded Image Analyzer & will give it a try. I had already downloaded a couple of FFT files but there was a dirth of info on how to use them. One said to "split channel to HSL or HSV". Have no idea what that means. I guess it's something you can do in the full version of Photoshop. I found some other instructions using the red channel. I was a able to select channels thanks to Graffi's Handy Actions but I'm still not cetain I'm operating the FFT function correctly. I was able to see some improvement but not a lot and it really affected the contrast and brightness but that was easy to correct in PSE adjustment layers. I ran the photo through Neat Image (NI) and that improved the photo and it was better than using just NI. This is not surprizing since NI is designed as a noise reducer and not a texture reducer.

I would think that other folks would be interested in the FFT process since I have seen questions on the forum about correcting print texture when working on photo restoration. I would really like to see the folks that produce PSE Techniques tackle this issue and describe what can be done with PSE. Again, thanks for the info!

[Daviskw]

Hi Mustang

I'm afraid most freeware programs don't come with a lot of help....Image Analyzer is no exception... that is why I posted the little example.

No channel work with this stand alone and it works!

Let me know how you get along with it... no expert but I get good results...at least with paper texture. There is also a routine that helps regain focus...I have not had a lot of luck with that.

Many other filters with the program but I prefer other procedures and do not use them so I would be little help with those.

Butch

[mustang]

Program didn't work well for me. I'm not sure it is working properly. I only get the lower half for the FFT window (i.e., the center of the central star is at the top margin of the page). In the other FFT programs I have the center of the central star is in the middle of the FFT window. How does it display for you?

FYI. I did finally get a good photo through a multi step process. First, just by chance, I discovered a slight improvment when the photo was scanned upside down. I was trying the technique of combining two scans done 180 degrees to each other. The combined photo was not as good as the upside down scan by itself. I used the FFT I downloaded from RetouchPro.com on upside down scan and got a little more improvement. Ran that result through Neat Image and experimented with some of the adjustments in the advanced mode and decided the auto mode was as good as I could get it. Also, I discovered that using the sharpening provision in Neat Image was superior to using either PSE high pass or USM. Neat Image sharpened the eyes w/o re-introducing paper texture. Sorry I can't post before and after photos - I don't know how to do it.

[mustang]

I don't but am curious about it. Try here.
http://www.retouchpro.com/forums/search.php?searchid=424657
It makes my head spin and I don't know how much translates to Elements

The one you found is the one I used. It has the best instructions. Look in their Tutorial archives for, "Using the FFT filter to remove photographic paper texture". However, to use the FFT program you will need a PSE plug-in that will allow you to select the red channel. I used Graffi's Handy Actions which has a channel selection option. I used the FFT proces in PSE 5. It works as a plug-in to PSE and works with .psd files. I don't know if it will work with earlyer versions.

Frankly, I don't know how well FFT works. I have only used it on only one photo and the reduction in paper texture was quite small. But with a different paper texture, scanner, etc. the result might be more dramatic. At anyrate it doesn't cost much to experiment. And you might want to try Image Analyzer too. The instructions, except for those related to channels, for the Retouch Pro program are applicable to the Image Analizer. This is a stand alone program and does not work with .psd files. It uses .jpg, .tiff, .gif file formats. See also Daviskw's instructions.

[Daviskw]

Hi there

Why don't you post an example picture and i will run it thru and see if we are doing it differently. With paper texture I usually get excellent results.

Butch

[mustang]

I haven't figured out how to attach a photo. It looks like you really have to reduce the size (97 KB for a .jpg) and I'm not sure of what value it would be at that point.

[Daviskw]

Hi Mustang

150 KB is plenty to display enough detail

Below is a full comparison...before and after over /under each other.

Notice the repetitive pattern of the paper texture in the top…. Notice to the right the frequency domain screen before the points and stars are blackened.

Now look at the bottom example…. The texture is mostly gone… look at the Frequency domain filter dialog and see which spots and stars I blackened.

If we are talking about the same thing you can see the effect of the filter.

Butch

Click on picture below
http://www.pixentral.com/hosted/1fxwoWOgPCCWJhJSQ3JEtRUVZuOVjB_thumb.jpg (http://www.pixentral.com/show.php?picture=1fxwoWOgPCCWJhJSQ3JEtRUVZuOVjB)