Cool! If the PDL high-level implementation isn’t zippy enough, I’d be happy to give some pointers on PP-izing it.
> On Mar 9, 2020, at 1:59 PM, Luis Mochan <[email protected]> wrote: > > Well, I found a nice fast algorithm for a direct and an inverse Radon (almost) > Transform and I think it lends itself for a nice implementation in > PDL. > > Press, William H. “Discrete Radon Transform Has an Exact, Fast Inverse > and Generalizes to Operations Other than Sums along Lines.” > Proceedings of the National Academy of Sciences 103, no. 51 (December > 19, 2006): 19249–54. https://doi.org/10.1073/pnas.0609228103. > > I'll post my solution here if I succeed. > > Thanks and regards, > Luis > > > On Mon, Mar 09, 2020 at 01:51:01PM -0600, Craig DeForest wrote: >> 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 >> > > >> _______________________________________________ >> pdl-general mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/pdl-general > > > -- > > 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] /\_/\__/ > GPG: 791EB9EB, C949 3F81 6D9B 1191 9A16 C2DF 5F0A C52B 791E B9EB > > > _______________________________________________ > pdl-general mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/pdl-general > _______________________________________________ pdl-general mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/pdl-general
