Hyperspectral Imagery: A New Technique for Targeting and Intelligence

Because all materials reflect, absorb, or emit photons in ways characteristic of their molecular makeup, a high-resolution trace of the intensity of the transmitted, reflected, emitted, or luminesced radiation versus wavelength forms a graphical record unique to a given material. The laboratory use of spectral measurements to identify minerals, pigments, and organic and inorganic compounds is an established and reliable technique and, the reasoning goes, if such could be done from air or space, it would give remote sensing a similar capability. Unfortunately, the useful absorption bands are narrow, 10 nm or less, and cannot be recorded with broad band systems such as Landsat. With the advent of the Airborne Visible Infrared Imaging Spectrometer AVIRIS and similar systems, the narrow band capability entered the remote sensing domain. AVIRIS is a true spectrometer, collecting reflected solar energy 0.4-2.5 micra in about 220 channels, or images, each in a spectral bandwidth of about 9.6 nm. This type of narrow band information is called hyperspectral. Hyperspectral Imagery, Remote Sensing, Landsat, Intelligence.