Fourier transform upsample/shift?

[Adam]

Benchmark tests created:
https://github.com/keflavich/image_registration/blob/master/examples/benchmarks_zoom.py
https://github.com/keflavich/image_registration/blob/master/examples/benchmarks_shift.py

They ought to be more extensive, but give the general results:
-fourier-based shifting is a little faster (maybe 50%), but follows
the same power-law
-fourier-based upsampling is marginally slower, but my test results so
far are questionable because of machine variability

Of course, with fftw3, one can increase the number of processes used
for the fft, which may speed things up.

On Sat, Dec 22, 2012 at 8:31 PM, Stéfan van der Walt <stefan at sun.ac.za> wrote:
> On Sat, Dec 22, 2012 at 5:24 PM, Adam Ginsburg <keflavich at gmail.com> wrote:
>> Reasonable idea.  I think they are faster for at least some cases, but they
>> also behave a little differently than other interpolation techniques.  So
>> put them all in a "fourier_interpolation.py" file, then put them somewhere
>> in transforms?
>
> Yes, I think some benchmarks would be interesting.  Otherwise, we may
> want to add sinc interpolation to ndimage and see if that yields the
> same results.
>
> Thanks!
> Stéfan
>
> --
>
>

-- 
Adam