{HEAD ~ A window} is applied to the spectral image data along {TAIL ~ the λ dimension}, to select a subset of the spectral image data corresponding to a range of wavelengths 
{ HEAD ~ A window } is applied to the spectral image data along { TAIL ~ the λ dimension } , to select a subset of the spectral image data corresponding to a range of wavelengths
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH