Improved surveillance technologies in support of security
This 'hyperspectral' sensor is able to detect not just visible light but infrared as well. The idea of hyperspectral sensing is not, however, merely to 'see' in the usual sense of optical telescopes and infrared nightscopes. This kind of detection - currently used on spy satellites and other surveillance systems - works differently. It is based on the same principles as the spectrometry used in astronomy and other scientific fields - that some classes of objects and substances will emit a unique set of wavelengths when stimulated by energy. In this case, everything on the surface below the satellite is stimulated by sunlight to emit its unique spectral fingerprint. If the computer crunching through all wavelengths is powerful enough, it is possible to identify points on the surface below where substances or objects of interest are to be found, and supply map coordinates for these. Some researchers focus on individual steps in the processing chain, such as atmospheric correction, precision geometric processing and subpixel analysis techniques. The Hawkeye partners developed tools that facilitate hyperspectral data exploitation by covering the entire end-to-end processing chain from sensor data to end-user products. These new tools integrate a range of algorithms into a common framework to detect and map forest changes, disturbed soil and targets of military concern. Fundamentally, the procedure is divided into two sequential steps: a processing and an exploitation step. The first step includes the conversion of raw sensor data into accurate map of emissivities on the ground. This allows physically meaningful quantities to be associated with a latitude, longitude and height on the Earth's surface. The subsequent step takes this measurement set as input and transforms it into more useful information. What sort of substances and objects the Hawkeye system is able to pick out of the area spanned? It is expected to pierce overhead camouflage that could deceive optical or thermal sensing; that it would be able to spot buried bombs, disturbed earth, concealed adits and other remnants of war. Moreover, automatic detection of specific materials would introduce a novel approach to environmental monitoring. Possible applications include detection of oil slicks in the sea after a shipwreck or the detection of gaseous pollutants in the event of an industrial accident. All this would seem to indicate that satellites with hyperspectral sensors are set to become a significant new player in the surveillance world, not only for security purposes but to boost environmental protection initiatives.
