[Insight-users] FFT Confusion

[Matt McCormick]

David Doria <daviddoria at ...> writes:

> 
> Thanks Matt. Maybe you could explain this in the documentation of the
> class (right now it is basically empty)? (and explain the choice of
> the name of the class too - i.e. why not just VnlFFTImageFilter? ).

Yes, the FFT classes are in need of documentation.  Please give this a look to
see if it makes sense: http://review.source.kitware.com/#change,775

> 
> Also, should I just use UnaryFunctorImageFilter to compute the complex
> conjugate of the resulting image? I'm surprised not to find a
> ConjugateImageFilter or similar. For a normalized correlation of
> images A and B in the frequency domain, I believe you are supposed to
> do
> 
> FFT(A) * conj(FFT(B))
> 

Gaetan's class should work well there, although you may want to use an adaptor
in that situation.

Best,
Matt