Hyperspectral analysis is a measurement process that relies on the identification and visual representation of reflected radiation from a broad range of the electromagnetic spectrum. This range of reflected light includes otherwise invisible wavelength groups, such as infrared and ultraviolet radiation. The basis of hyperspectral analysis is the physical characteristic of all materials to reflect light from these spectrum ranges in a very specific, measurable manner. These unique electromagnetic signatures are read by hyperspectral sensors and visually depicted on a display or read out. These read outs or images are structured as layered three-dimensional "cubes" that allow very accurate compositional analysis of the scanned material.
Every material reflects visible light in a unique, identifiable way. The manner in which this reflected light is seen or collected gives all objects their specific colors and surface textures. It is not just visible light that is reflected in a specific fashion, though. Light from areas of the electromagnetic spectrum that are invisible to the human eye are also reflected in very specific ways by different materials. Reflected light from these spectrum slices, particularly ultraviolet and infrared light, may be read by specialist sensors and stacked or layered to create wonderfully graphic and accurate representations of the composition of materials.
These hyperspectral sensors and the unique three-dimensional images they create are at the heart of hyperspectral analysis. The hyperspectral "signatures" for most materials are known, and this allows analysts to accurately identify the exact material make up of any scanned material. The technology makes light work of pursuits such as mineral exploration, which was previously arduous and time consuming. Hyperspectral sensors mounted in aircraft can create incredibly detailed multi-dimensional models of large tracts of land in a short period. These models consist of layers representing a specific reflected wavelength and providing a broad selection of material identification.
The technology has many uses outside the obvious geology and mineralogy applications. For example, the agricultural industry can benefit from hyperspectral analysis, as the images generated can indicate nutrient and water levels in crop stands. The presence of disease causing animal proteins in livestock feeds can also be detected using hyperspectral imaging. In this way, the imaging assists in avoiding conditions such as mad cow disease.
The military and law enforcement arenas also see considerable use of hyperspectral analysis. Hyperspectral images can help investigators identify recently excavated graves or buried artifacts, for instance. The same functionality allows for the identification of subterranean emplacements in military applications as well. Hyperspectral imaging also allows military personal to track troop movements and differentiate between camouflage paint and living vegetation. This technology also been used extensively in humanitarian projects to identify old minefields and weapons caches.
