Spectral envelope refers to the edges of the spectral properties of a feature, expressed as the range of brightness in the electromagnetic spectrum, as measured by a spectrometer.
... town is 74.50% White, 11.00% African American, 1.00% Native American, 1.88% Asian, 0.00% Pacific Islander, 7.00% from other races, and 4.62% from two or more races. 14.38% ...