Band-pass frequencies

[dzenanz]

Reduce high frequencies to reduce noise, and low frequencies to reduce influence of uneven illumination. Do it in Fourier space. Possibly ignore the highest frequencies entirely by cropping.

[thewtex]

Related:

https://github.com/InsightSoftwareConsortium/ITK/blob/master/Modules/Filtering/ImageFrequency/include/itkFrequencyBandImageFilter.h

https://github.com/KitwareMedical/ITKUltrasound/blob/master/include/itkButterworthBandpass1DFilterFunction.h

[dzenanz]

A fancier band-pass filtering (e.g. Butterworth) should be enabled when this is merged: InsightSoftwareConsortium/ITK#149