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Re: FFT OF A NON RECTANGULAR IMAGE [message #63169 is a reply to message #63071]

Tue, 28 October 2008 14:21

pgrigis
Messages: 436
Registered: September 2007

Senior Member

R.G. Stockwell wrote:
> <pgrigis@gmail.com> wrote in message
> news:3cb784b7-dfed-4c87-a2ab-d775d1edec0e@f40g2000pri.google groups.com...
>> Maybe you could do a (slow) FT instead of FFT?
>>
>> Ciao,
>>
>> Paolo
>
>
> Not directly. DFT and FFT are the same, the difference is in how the
> calculation is done.

What I meant was, for every frequency vector (kx,ky),
evaluate the Furier transform F(kx,ky) by computing
the integral of the input function (or table of values)
multiplied by the Fourier basis function of kx,ky over
the elliptical domain....
On second thought, this would be extremly slow...

Ciao,
Paolo

>
>
> One could simply do a series of one dimensional FFTs on the data (each of
> differing length,
> and just combine them into a couple of image. i.e. just look at an image of
> kx spectra,
> then a different image of ky spectra.
>
> Also, one can write the 2D FT as a series of 1D ffts, and perhaps that
> approach
> would get what the OP wants (if that is what you are talking about).
>
>
> Cheers,
> bob

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[Message index]

		Re: FFT OF A NON RECTANGULAR IMAGE By: R.G. Stockwell on Tue, 28 October 2008 14:07
		Re: FFT OF A NON RECTANGULAR IMAGE By: pgrigis on Tue, 28 October 2008 13:15
		Re: FFT OF A NON RECTANGULAR IMAGE By: R.G. Stockwell on Tue, 28 October 2008 11:58
		Re: FFT OF A NON RECTANGULAR IMAGE By: pgrigis on Tue, 28 October 2008 14:21

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