Hyperspectral Remote Sensing

The section remote sensing of BGR uses hyperspectral data for mineralogical, lithological and soil mapping and quantification in different scales. The major focus is on the data fusion of spectral results with information of geology, geophysics, geochemistry and mineralogy as well as the development of expert systems for synergetic exploitation of those various information. It facilitates the determination of important information for exploration and mineral resource exploitation such as spatial distributions of minerals and mineral paragenesis, hardness of rocks or detection of certain minerals. Characterization of soils and mapping of soils on regional scale, as well as monitoring of tailings and mining progress monitoring are further important fields of activity. Further applications are the detection of hydro carbons in rocks and soils as well as the support of the assessment of potential hydro carbon bearing lithologies or rock units.

figure modified after Markelowitz (http://www.markelowitz.com/Hyperspectral.html)

Hyperspectral remote sensing (Imaging Spectroscopy) acquires reflected electromagnetic radiation (e.g. reflected sun light) and the emitted radiation from a given surface by a large number of very narrow spectral channels resulting in a continuous spectrum. Such a spectrum allows the identification and quantification of the surfaces constituents by their diagnostic spectral features created by the interaction of the electromagnetic radiation with atoms and molecules of the observed material. Spectral features appear as reflectance minima, so called absorption or absorption bands, or as reflectance maxima (peaks). The position and shape as well as the intensity of the feature are mathematically described and extracted to analyze hyperspectral data with regard to the requirements.

For the spectral analytics, the following spectral wavelengths are used:

• Solar optical range (reflectance of the suns radiation) – consists of the visible light, near infrared and shortwave infrared (VNIR-SWIR; 0.4 – 2.5 µm).
• Emittance range - combines the wavelength range from the mid infrared (MIR; 3 -5 µm) and the longwave infrared (LWIR; 7 – 12 µm), also called thermal infrared (TIR).

Hyperspectral sensors are used in the laboratory, in the field and in the air. The data acquisition is carried out either punctual or along profiles with ASD, Spectral Evolution and Agilent FTIR or by imaging with the HySpex Mjolnir VS-620 camera system, operated on a drone, or AISA FENIX and AISA OWL, which are also flown on the BGR Helicopter and depending on requirements together with the geophysical sensors.

more information

Projects

• MultiMiner - Multi Source and Multi Scale Earth Observation and Novel Machine Learning for Mineral Exploration and Mine Site Monitoring
  
• HYPGEO – Neue Verfahren zur Exploration mineralischer Rohstoffe
  
• REEMAP - Hyperspectral mapping of rare earth elements
  
• Hyperspektrale Charakterisierung verschiedener Lagerstättentypen in Vorbereitung zur EnMAP Mission