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