Computer Graphics with Photoshop

Author

Halftone Removal

Tom Kinter

2005-06-08, 7:14 pm

Greetings,

I am wondering if there is a plug-in avaliable to do halftone removal. If there aren't are there some good photoshop techniques. I do have some luck with multiple resizing steps but I would like something more robust. Sice the patterns are so regular and
obvious, I know that Fourier techniques would work but I'd like to see an automated method.

Thanks for your time!

Tom
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Tom Kinter tmk@mayo.edu 507-284-4981
Mayo Foundation Rochester MN 55905 USA
http://www.mayo.edu/ultrasound
Tom's Place http://www.tkinter.smig.net
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Photo-Plugins

2005-06-08, 7:16 pm

Tom Kinter wrote:
> Greetings,
>
> I am wondering if there is a plug-in avaliable to do halftone removal. If there aren't are there some good photoshop techniques. I do have some luck with multiple resizing steps but I would like something more robust. Sice the patterns are so regular an
d obvious, I know that Fourier techniques would work but I'd like to see an automated method.
>
> Thanks for your time!
>
> Tom
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Tom Kinter tmk@mayo.edu 507-284-4981
> Mayo Foundation Rochester MN 55905 USA
> http://www.mayo.edu/ultrasound
> Tom's Place http://www.tkinter.smig.net
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
>
I wrote this recently:
It's going to sound greek to you because it is actually written in greek
http://www.dpgr.gr/index.php?page=FourierPS
But if you check out the links and the pictures, I'm sure you'll get the
point.
Mr Chirokov's FFT plugins are available at
http://plasma.mem.drexel.edu/chirokov/archive.htm#FFT

An (awfull) translation of the article in english can be obtained here:
http://babelfish.altavista.com/

An alternative approach is to apply multiple passes with NeatImage, a
noise reduction application, also available as a Photoshop plugin.

Thomas Kinter

2005-06-13, 5:45 pm

I tend to do things the old-fashioned way:

first, scan at as high a resolution as possible - at minimum, double the size you need the picture (the higher the better).

second, use the smart-blur tool to blend the half-tone dots (an even older technique is to do a gaussian blur set at 1.5 pixels).

third, resize the picture to the lower resolution at which you will use it. this usually does a decent job - the final resizing sharpens up the edges.

best regards,

Tom Kinter (T.S. Kinter)

RSD99

2005-06-13, 11:15 pm

Fourier methods actually work quite well ... you might take a look at some
of the Reindeer Graphics Image Processing tutorials and plugins.

http://www.reindeergraphics.com/

http://www.reindeergraphics.com/tutorial/index.shtml

The exact procedure for halftone removal is described at
http://www.reindeergraphics.com/tut.../fourier13.html

"Tom Kinter" <tmk@mayo.edu> wrote in message
news:d873a8$da5$1@tribune.mayo.edu...
> Greetings,
>
> I am wondering if there is a plug-in avaliable to do halftone removal. If
there aren't are there some good photoshop techniques. I do have some luck
with multiple resizing steps but I would like something more robust. Sice
the patterns are so regular and obvious, I know that Fourier techniques
would work but I'd like to see an automated method.
>
> Thanks for your time!
>
> Tom
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Tom Kinter tmk@mayo.edu 507-284-4981
> Mayo Foundation Rochester MN 55905 USA
> http://www.mayo.edu/ultrasound
> Tom's Place http://www.tkinter.smig.net
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
>

RSD99

2005-06-13, 11:15 pm

Also see
http://www.retouchpro.com/forums/sh...=3&pp=15&highli
ght=fft

Page down to the last posting ... 'Summary' by Cameraken.

"RSD99" <rsdwla.NOSPAM@gte.net> wrote in message
news:nvore.7024$9a1.6049@trnddc01...
> Fourier methods actually work quite well ... you might take a look at
some
> of the Reindeer Graphics Image Processing tutorials and plugins.
>
> http://www.reindeergraphics.com/
>
> http://www.reindeergraphics.com/tutorial/index.shtml
>
> The exact procedure for halftone removal is described at
> http://www.reindeergraphics.com/tut.../fourier13.html
>
>
>
>
>
> "Tom Kinter" <tmk@mayo.edu> wrote in message
> news:d873a8$da5$1@tribune.mayo.edu...
If[color=darkred]
> there aren't are there some good photoshop techniques. I do have some
luck
> with multiple resizing steps but I would like something more robust. Sice
> the patterns are so regular and obvious, I know that Fourier techniques
> would work but I'd like to see an automated method.
>
>