RetouchPRO

RetouchPRO (http://www.retouchpro.com/forums/)
-   Software (http://www.retouchpro.com/forums/software/)
-   -   Here is FFT for 64 bit photoshop (http://www.retouchpro.com/forums/software/33084-here-fft-64-bit-photoshop.html)

Ron Chambers 10-30-2017 08:42 AM

Re: Here is FFT for 64 bit photoshop
 
Chain
Even with the not perfect programs you could try a few things if you wish. The other pieces are already in PS. Let me know and I'll walk you through a few of them. Pulling together in actions or scripts would naturally follow.
You mentioned the symmetry in the transform output. It is actually anti-symmetry (quadrant 1 being upper right) as q 2 is a mirror of 1 along the x positive axis, q4 is mirror of 1 about y positive axis and I'll let you guess about q3. The phase info is a bit more complicated. I mentioned earlier the distance between stars is inversely related to the pimples on the original image.

You can make a couple of synthetic images and try some of this stuff.

Let me know as I'm still down. Mind hasn't stopped.
RONC

Chain 10-31-2017 01:03 PM

Re: Here is FFT for 64 bit photoshop
 
If i number the quadrants from 1-4, starting top left, then top right, bottom left, bottom right, then I see that 1 and 3 are identical, and 2 and 4 are identical. Just rotated. So basically half the red channel is redundant data.

This means that when removing a "star" you only need to do half the image, then you can duplicate and rotate the work over the 2nd half of the image. But the difference between the two pairs are so small you can actually do just 1/4 of the image and mirror/rotate that.

But please, do expand on the other things you can do with this besides removing repeating patterns. :)

Ron Chambers 10-31-2017 02:39 PM

Re: Here is FFT for 64 bit photoshop
 
Quote:

Originally Posted by Chain (Post 333879)
If i number the quadrants from 1-4, starting top left, then top right, bottom left, bottom right, then I see that 1 and 3 are identical, and 2 and 4 are identical. Just rotated. So basically half the red channel is redundant data.

This means that when removing a "star" you only need to do half the image, then you can duplicate and rotate the work over the 2nd half of the image. But the difference between the two pairs are so small you can actually do just 1/4 of the image and mirror/rotate that.

But please, do expand on the other things you can do with this besides removing repeating patterns. :)

It true you only need 2 quadrants in my system 1 and 4. The FT I wrote for other work (non pc) only computed those thereby reducing costs by 2 in cpu and memory. Reason I number my quadrants like I do is that spatial frequency 0,0 is the center of the the image. Otherwise the mass of energy would be in the 4 corners.
Now to further confuse you, the original image has its 0,0 in the upper left corner. So try a test. Take your test image and rotate 5 degrees clock wise. Crop so only non-padded pixels are shown. Delete outside of crop. Forward transform and stare for a bit. Go to channels and click deactivate all but red. Stare more. Go to Layer Adjustments and do Levels. Move arrows to show the stars really well. Stare again. Have to rethink symmetry. Might be a good way to align scanned image with pimples. I'll wait on your comments. You could attach the images at different stages for us to discuss and others to understand.

Let's try interpolation next. Take your test and forward transform. Go to Canvas and double canvas size and fill color equal black. Inverse transform and your image will be twice size. You could reload test image and interpolate using Photoshop and then compare the two. Edges are off limits for now in discussions.

I'm trying to get granddaughter to bring her pc so she can run examples for further tests.

Enjoy Fourier Transforms 101 with no equations.

RONC

Chain 11-01-2017 02:34 PM

Re: Here is FFT for 64 bit photoshop
 
Yeah, edges always gets messed up when using the FT stuff. There's also always some other subtle changes to brightness/contrast in the image.

Interpolation worked. That was neat. End result was very gray and low contrast though. Brightening the outside in the red channel made a funky white pattern creep into the image. :)

Rotation of the image (or rather the patterns in the image) caused the lines of stars to rotate by the same amount.

---

I'm really busy these days so haven't played with it much. I don't really understand too much about FTs to be honest. :S

SmpdNC 11-02-2017 12:30 PM

FFT for Photoshop CC
 
My apologies if I missed earlier posts regarding this question, I scanned through the 17 pages but failed to see it specifically mentioned.

I downloaded the files and copied them over per the instructions and I still do not see them listed when I open Photoshop CC.

I appreciate your assistance.

Ron Chambers 11-02-2017 03:54 PM

Re: Here is FFT for 64 bit photoshop
 
Not sure which set you downloaded but the original should be in Filter>Fourier Transform and the set I placed for test Filter>Fourier Transform - RC.
Have a look and get back to us.
RONC

Ron Chambers 11-04-2017 08:09 PM

Re: Here is FFT for 64 bit photoshop
 
Quote:

Originally Posted by Chain (Post 333882)
Yeah, edges always gets messed up when using the FT stuff. There's also always some other subtle changes to brightness/contrast in the image.

Interpolation worked. That was neat. End result was very gray and low contrast though. Brightening the outside in the red channel made a funky white pattern creep into the image. :)

Rotation of the image (or rather the patterns in the image) caused the lines of stars to rotate by the same amount.

---

I'm really busy these days so haven't played with it much. I don't really understand too much about FTs to be honest. :S

I'll find a simple tutorial on Fourier transform and pass in on.
The particular implementation of the Fourier transform is a cause of the edge difference. I'll explain more later. It is a trade off between filter length vs edge.
The interpolation is a not correct because of the scaling bugs in this version.
The use of the Levels was to be for viewing only. The stars should be easier to find. Doing an inverse transform is a waste of time.

RONC

Ron Chambers 11-13-2017 10:07 PM

Re: Here is FFT for 64 bit photoshop
 
https://betterexplained.com/articles...ier-transform/
Rather simplified tutorial for 1D Fourier transform.

I'm working again on the program. Going slowly but I think I will load another version by the end of the week.
RONC


All times are GMT -6. The time now is 11:39 AM.

Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
SEO by vBSEO ©2011, Crawlability, Inc.
Copyright 2016 Doug Nelson. All Rights Reserved