This is mincfft it uses FFTW to do all the heavy lifting

Comments and changes to: a.janke@gmail.com

A simple example would be as such for a 3D FFT of a 3D minc volume

   mincfft -3D in.mnc out.mnc

In this case out.mnc would be a 4D minc file with a vector_dimension for
real + imaginary. Most people would instead want a magnitude or phase image.
Do this as such:

   mincfft -3D in.mnc out.mnc -phase phase.mnc -magnitude mag.mnc

This will result in two additional 3D minc files, phase.mnc and mag.mnc

You can also do 2D and 1D FFT's:

   mincfft -2D in.mnc out.mnc -magnitude mag.mnc
   mincfft -1D in.mnc out.mnc -magnitude mag.mnc

Note that the dimensions that FFT'd are the fastest varying, so a typical ZYX
ordered volume a 2D FFT will perform a 2D FFT of the X+Y dimensions for each
Z slice in a volume. A 1D FFT will perform a 1D FFT of each X column in a ZYX
volume.

If you want to FFT any other dimension you will need to use the -dimorder
argument. So in order to perform a 2D FFT of the Z+X dimensions for each Y slice
do this:

   mincfft -2D -dimorder yspace,xspace,zspace in.mnc out.mnc -magnitude mag.mnc

Note that the resulting volumes will have the dimension order as specfied when
the FFT is performed. If you would like to reorder the output MINC volume in
a different order to the FFT you will need to use mincreshape -dimorder ...
after mincfft.