The “fft” option in PDL::Transform::map has to do with interpolation method, and isn’t directly relevant (unfortunately). I used a subset of the radon transform in one of my papers (see the appendix; link here: https://bit.ly/38Bylg3 <https://bit.ly/38Bylg3>). That was all roll-your-own, though: I never packaged it up as a full radon transform.
If I were implementing one in the general case in PDL itself, I’d do something like a Fourier transform followed by a PDL::Transform::map to radial coordinates followed by an inverse Fourier transform. PDL::FFTW3 would be the right tool for that. There’s probably something in the GSL already, though — if so, one could just link to that. > On Mar 9, 2020, at 1:39 PM, Boyd Duffee <[email protected]> wrote: > > Hey Luis, > > From the deafening silence to your question, I'd say no. I had a quick look > around CPAN and I see nothing for Radon in PDL or Perl in general. > > Then I had a look at what a Radon Transform > <https://en.wikipedia.org/wiki/Radon_transform> actually is and it is **well > cool**! We were talking last week about the episode of House with the > bullet fragments and the MRI machine and started asking, how _do_ you get a > 3D image from a bunch of attenuations? > > As it's not far off the Fourier transform, I'd say it's possible and maybe > PDL::Transform's map <https://metacpan.org/pod/PDL::Transform#map1> function > with it's { map => 'fft' } option is a place to start hacking. I'll have > some free time in a couple of months if you want a willing novice-to-PDL > collaborator. It sounds like something that Perl should have in it's toolbox > if we want our language to be serious about Scientific Perl. I think I've > got a "tuit" around here somewhere. :) > > Saludos, > Boyd > > On Thu, Mar 5, 2020 at 4:37 AM Luis Mochan <[email protected] > <mailto:[email protected]>> wrote: > Hi, > > Is there an implementation of the Radon transform and its inverse in > PDL? Or some implementation which may be called from PDL? > > Regards, > Luis > > > > -- > > o > W. Luis Mochán, | tel:(52)(777)329-1734 /<(*) > Instituto de Ciencias Físicas, UNAM | fax:(52)(777)317-5388 `>/ /\ > Apdo. Postal 48-3, 62251 | (*)/\/ \ > Cuernavaca, Morelos, México | [email protected] > <mailto:[email protected]> /\_/\__/ > GPG: 791EB9EB, C949 3F81 6D9B 1191 9A16 C2DF 5F0A C52B 791E B9EB > > > _______________________________________________ > pdl-general mailing list > [email protected] <mailto:[email protected]> > https://lists.sourceforge.net/lists/listinfo/pdl-general > <https://lists.sourceforge.net/lists/listinfo/pdl-general> > > > -- > Boyd Duffee > Bring on a brand-new renaissance - TTH > _______________________________________________ > pdl-general mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/pdl-general
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