Prev: Angle Recovery in Fourier Mellin Image Registration
Next: How to make isosurface() work with uint8 data
From: Rene on 26 May 2010 09:42
Is it possible to specify arbitrary bin locations using the FFT function? So, I don't want the bin locations to be determined by by sampling rate and number of FFT bins, but instead I want to be able to specify specific bin locations that aren't evenly or regularly spaced. Thanks, Rene Allard.
From: Walter Roberson on 26 May 2010 10:24
Rene wrote:
> Is it possible to specify arbitrary bin locations using the FFT
> function? So, I don't want the bin locations to be determined by by
> sampling rate and number of FFT bins, but instead I want to be able to
> specify specific bin locations that aren't evenly or regularly spaced.

No, the fft() function is only for uniform data. You would need nfft, a
non-uniform fft. There have been some references to it lately. There is
a free compatible package for Linux that should in theory work on other
systems, but at least one person had non-trivial difficulties getting it
to compile and install in Windows.
From: Md Sahidullah on 2 Jun 2010 07:40
NUFFT i.e. Non Uniform FFT is an interesting idea proposed by S. Bagchi and SK. Mitra .
(Ref.THE NONUNIFORM DISCRETE FOURIER TRANSFORM AND ITS SIGNAL PROCESSING APPLICATIONS
Author: SK Mitra & S. Bagchi Publisher: Kluwer)
for code you may use http://www.eecs.umich.edu/~fessler/irt/fessler.tgz with MATLAB. You can set your own FFT bins there.

Thanks & Regards
Sahidullah

Walter Roberson <roberson(a)hushmail.com> wrote in message <EaaLn.17953$h57.8103(a)newsfe22.iad>...
> Rene wrote:
> > Is it possible to specify arbitrary bin locations using the FFT
> > function? So, I don't want the bin locations to be determined by by
> > sampling rate and number of FFT bins, but instead I want to be able to
> > specify specific bin locations that aren't evenly or regularly spaced.
>
> No, the fft() function is only for uniform data. You would need nfft, a
> non-uniform fft. There have been some references to it lately. There is
> a free compatible package for Linux that should in theory work on other
> systems, but at least one person had non-trivial difficulties getting it
> to compile and install in Windows.
 | 
Pages: 1
Prev: Angle Recovery in Fourier Mellin Image Registration
Next: How to make isosurface() work with uint8 data