[Insight-users] ifft

Jesse C Cronce croncejc at mrctr.upmc.edu
Wed Oct 12 17:33:20 EDT 2005


Thanks Carlos, that helped a lot.

I did that, and what the FFTW outputs is a lot closer to what I really
want than the VnlFFT was outputting. However, the FFTW inverse fourier
transform returns an image that is scaled - if I pass in an image that
is 128 x 512 (complex floats), the output image is 128 x 1022. 

According to the documentation on the FFTW website, what I want is an
image that has been normalized (which is apparently what matlab does).
Does ITK provide an easy way to do this ? Or is it a simple matter of
moving the pixels around to get the correct image ? Any suggestions
would be greatly appreciated.

Thanks,
JCC

On Wed, 2005-10-12 at 08:52 -0300, Carlos Santos wrote:
> Hi,
> 
> There are some reports of problems with the VnlFFT classes, the
> suggested solution is using FFTW (http://fftw.org/) instead.
> See:
> http://www.itk.org/pipermail/insight-users/2005-July/013900.html
> for a more thorough discussion.
> 
> Hope this helps,
> Carlos
> 
> On 10/11/05, Jesse C Cronce <croncejc at mrctr.upmc.edu> wrote:
> > All,
> >
> >     Does anyone know if there is an equivalent call to the Matlab call
> > ifft2 in ITK ?
> >
> > When I compare values computed by ifft2 in matlab on an identical matrix
> > that I put through the itkVnlFFTComplexConjugateToRealImageFilter the
> > pixel values are extremely different.
> >
> > Thanks,
> > JCC
> >
> > _______________________________________________
> > Insight-users mailing list
> > Insight-users at itk.org
> > http://www.itk.org/mailman/listinfo/insight-users
> >



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