bandbank -- isotropic image spectral decomposition and filtering

Tristan Ursell
Bandpass filter bank
Jan 2017
Im2=bandbank(Im1,dF,NF)
Im2=bandbank(Im1,dF,NF,beta)
Im2=bandbank(Im1,[band_vec],beta)

Im1 = input image (single channel)
dF = stepsize in radial frequency space
NF = number of filters applied
NF=1 means no filter
NF=2 means low pass and high pass about dF
NF>2 bandpass filters in steps of dF

Im2 = spectrally decomposed output images from Im1

The optional parameter 'beta' sets the sharpness of the frequency cutoff
between the bands, higher numbers are sharper cutoffs -- smoother cutoffs
reduce ringing, but have mixed fequency regions with other bands. The
default value is beta=0.5.

The decomposed images have the property that 'sum(Im2,3)=Im1' (to a good approximation).