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Removing a Line Screen
Posted: Sat Aug 01, 2009 10:38 am
by Brian Pugh
Hi,
I have an old photograph from a Flickr site that has a line screen
Is there any way in XnView that I can remove the screen, or
is there a plugin that can do the job?
Thanks,
Brian
Re: Removing a Line Screen
Posted: Mon Aug 03, 2009 9:55 am
by xnview
Crop?
Re: Removing a Line Screen
Posted: Mon Aug 03, 2009 6:12 pm
by Brian Pugh
Thanks, Pierre,
Sorry, due to my first post, I think we've got the wires crossed (well I have!)
Before continuous tone images, a line screen was put on an image for it
to print. A newspaper would probably use an 85 lpi screen, maybe 100.
High quality printing (magazines, etc) would probably use something like
150 or more
The more dots, the better quality. More dots close together would result
in an area of the image being darker than a few dots
Does that help?
Brian
Re: Removing a Line Screen
Posted: Mon Aug 03, 2009 7:30 pm
by XnTriq
Re: Removing a Line Screen
Posted: Wed Aug 05, 2009 9:32 am
by Brian Pugh
XnTriq,
Many thanks for your reply and suggestions - quite a bit to go at there!
The Photoshop solution seems easy enough - I'll give it a go tonight
Thanks again,
Brian
Re: Removing a Line Screen
Posted: Wed Aug 05, 2009 10:51 am
by rra
You might want to take a look at the program "image analyzer" from Michael Vinther
http://meesoft.logicnet.dk
It is free and it contains (next to lots of other filters) also an option to
edit an image in the fourier plane.
Stripes and regular spaced dots can easily be seen and interactively removed in this plane,
then return back to the normal plane to view the effect, save, et voila !!
I use it frequenlty to remove all sorts of screening of scanned foto-images.
René
Re: Removing a Line Screen
Posted: Thu Aug 06, 2009 8:10 am
by Brian Pugh
Rene,
Downloaded Image Analyzer, but couldn't see how to edit an
image using the Fourier plane. Any suggestions as to how
to do this?
Thanks for your interest, anyway
Brian
Re: Removing a Line Screen
Posted: Thu Aug 06, 2009 9:14 am
by rra
Downloaded Image Analyzer, but couldn't see how to edit an
image using the Fourier plane. Any suggestions as to how
to do this?
I admit it is a little bit hidden between other options:
go to:
/Operations/Filters/Frequency domain filter
You need a fast computer for this kind of operations !!
There are also limitations using grayscale images when using other filters.
Good luck,
René
Re: Removing a Line Screen
Posted: Thu Aug 06, 2009 11:06 am
by Brian Pugh
Rene,
OK, saw that, but didn't know what it was!
Thanks again
Re: Removing a Line Screen
Posted: Thu Aug 06, 2009 9:45 pm
by XnTriq
Re: Removing a Line Screen
Posted: Fri Aug 07, 2009 6:20 am
by rra
great links you gave there XnTriq,
the plugin also seems to be a lot faster.
I noticed the plugins only work with RBG images,
so one has to convert it first to RBG and afterwards back to grey.
Now if Xnview had some basic editing (in this case: erasing) features
we wouldn't have to divert to Photoshop at all
René
Re: Removing a Line Screen
Posted: Fri Aug 07, 2009 8:15 pm
by XnTriq
Re: Removing a Line Screen
Posted: Sat Aug 08, 2009 11:24 am
by rra
Well actualy,
I like best the one I came up with myself: the MIcheal Vinther's implementation.
With this FFT one can seen the different spacial frequencies much clearer, and if one returns back to the original plane (iFFT), the image still is colored.
With the implementation of Chirokov the image returns grayscale, one has to use some techniques to add the colored layer back.
Disadvantage of the Michael Vinthers implementation is ofcourse the fact that you have to use hist "mage analyser" program to do the filtering,
a plugin is easier to use. .
By the way: 3 of your links (2,3 and 4) seem to be dead ?
René
Re: Removing a Line Screen
Posted: Sun Aug 09, 2009 10:30 pm
by XnTriq
rra wrote:By the way: 3 of your links (2,3 and 4) seem to be dead ?
I just double-checked the downloads with Firefox, Internet Explorer (browser caches cleared), and also LeechFTP.
Code: Select all
http://www.alexchirokov.narod.ru/archive/Light_AdobeFilter_Release_15JAN_2004.zip
http://web.archive.org/web/20051102154559/http://www.pages.drexel.edu/~avc25/archive/FFT_Adobe_Filter_8Apr_2005.zip
http://web.archive.org/web/20051102153400/http://www.pages.drexel.edu/~avc25/archive/FFT_RGB_PlugIns_13April_2005.zip
No problems
rra wrote:With this FFT one can seen the different spacial frequencies much clearer, and if one returns back to the original plane (iFFT), the image still is colored.
I must be missing something obvious here
How do I preserve the color information in Image Analyzer?
- v1.30 (2008)
- Operations » Transformations » Fourier transform
- Operations » Transformations » Inverse Fourier transform
- v1.22.3 (2005)
- Image » Make map » Fourier transform
- Map » Inverse Fourier transform
————————————————————————————————————————————————>8
ADP Tools: DenoiseMyImage
DenoiseMyImage is a freeware/shareware that can remove digital noise from your photos.
DenoiseMyImage employs modified NonLocalMeans algorithm (from Buades, Coll, Morel), that is state-of-art in removing digital noise from photos. Our algoritm is more than 50 times faster original one and preserves its advantages. Neither waveletet denoising (i.e. BayesShrink) nor anisotropic diffusion have same or better results.
Re: Removing a Line Screen
Posted: Mon Aug 10, 2009 6:02 am
by rra
You have to use another option, the one I mentioned in a previous message:
/Operations/Filters/Frequency domain filter.
You edit with a brush-eraser with selectable size, once done, hit OK ; that's all there is to it .
I am not sure about older versions, but this one is available for version 1.30 .
By the way: links 3 & 4 are still dead, link2 does seem to work, strange indeed .
René