# Re: Discrete Fourier Transform (DFT) viewer and/or file format

*Date*: Mon, 13 Nov 2017 10:31:27 +0100*From*: <tomas@xxxxxxxxxx>*Subject*: Re: Discrete Fourier Transform (DFT) viewer and/or file format

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Sun, Nov 12, 2017 at 07:45:13PM -0800, Dan Hitt wrote: > I have some DFTs that i wish to inspect. (Apparently DFT is a common > acronym, but here i mean Discrete Fourier Transform. And properly > speaking it doesn't make sense to inspect a transform, but only to > inspect transformed data, but i'm speaking colloquially.) Uh, oh. To answer that without getting lost in Hilbert Space means consulting my (rusty) crystal ball :-) Now more seriously: what do you mean by "inspecting" a DFT? A DFT is just a trick to approximate a Fourier transform on an (approximate) function. Are you talking about one dimensional functions (e.g. a function of time) or two (three, etc.) dimensional functions? Their transforms are, correspondingly, one, two (and so on) dimensional functions, so the visualization techniques vary, depending on dimensionality and on the conventions current in the field (engineering, social sciences, maths, whatever). I'd recommend looking into some of the many (excellent) scientific packages having a visualization components, each one of which has a teeming community willing to help you. For three examples off the top of my head (all three packaged in Debian): GNU Octave https://www.gnu.org/software/octave/ NumPy http://www.numpy.org/ GNU R https://www.r-project.org/ The last one is touted as "statistical package", but let me tell you: all three are not only capable of visualizing (the result of) a discrete DFT, but all three can calculate one for you :-) Now if you are trying to visualize the result of a DFT on an image (a special two dimensional case, where you think of the discrete elements as of pixels), then perhaps a graphical package (e.g. The Gimp) is your friend. Also packaged in Debian. For more of those "scientific computing" packages, browsing this https://wiki.debian.org/DebianScience might be of interest (or just drop "Debian scientific computing" into your favourite search engine, which hopefully ain't Google). Enjoy - -- tomás -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iEYEARECAAYFAloJZm8ACgkQBcgs9XrR2kYEmwCdHEeR7zsVXPrNIxSORJEupCmG DnoAn01e7MOZnNVs4aIchkrsu6Fh6ASi =qyUp -----END PGP SIGNATURE-----

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