By Dr. Michaela Frei

Head of the Remote Sensing Working Group at the Federal Institute of Geoscience and Natural Resources (BGR), Germany

GSAf seminar series

Date: 30 April 2021

14:00 (GMT)

15:00 Nigeria time, 16:00 South Africa time

Online Seminar (Google Meet)



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Dr. Michaela Frei is Head of the Remote Sensing Working Group at the Federal Institute of Geoscience and Natural Resources (BGR), Germany. She received her doctorate at the Ludwig-Maximilians- University, Munich, Germany. After teaching and research experiences in Germany, China and South Arica in the fields of Geoscientific Remote Sensing and GIS Dr. Michaela Frei joined BGR in 2014. Main research interests are synergies of optical and radar remote sensing and remote sensing based applications. She is reviewer of the Journal of African Earth Sciences, International Society for Photogrammetry and Remote Sensing etc.. Dr. Frei and her working group are members of the German Copernicus Expert Group and Copernicus related advisory boards of the European commission for the further development of the Copernicus Mission including the upcoming Hyperspectral Spaceborne Sensor Sentinel CHIME. The Remote Sensing Working Group at BGR currently implemented the first German Ground Motion Service (BBD). Dr. Frei is leading initiator for the initiative and development of an European Ground Motion Service, and member of the EGMS Advisory Board. Multiscale Applications to Exploration Concepts in Geological Hyperspectral Remote Sensing

Authors: Dr. Michaela Frei and Dr. Martin Schodlok

Worldwide exploration concepts including multispectral and hyperspectral remote sensing are recently being re- evaluated, enhanced or developed, to reduce costs and increase efficiency in raw materials prospection, and exploitation processes. Therefore, multiscale hyperspectral data from laboratory, airborne and space are investigated, and data processing and validation chains are automatized and validated by mineralogical and geochemical data.

Airborne, in situ outcrop, laboratory and drill core image data covering the visible, near infrared shortwave infrared wavelength range (VNIR-SWIR, 0.4 – 2.5 μm) and long wave infrared wavelength range (LWIR, 7.7 – 12.5 μm) were acquired at different scales with a spatial resolution varying from 25 μm, to several meters per pixel. The selection and performance of geometric,  atmospheric and radiometric correction algorithms are assessed. Spectral analysis based on multispectral feature extraction methods are applied to VNIR, SWIR and LWIR hyperspectral data. In case of ambiguous results, a combination of diagnostic spectral features derived from the full wavelength range is applied. Geochemical data (μEDXRF and LIBS ) e.g. of selected areas are used for validation. Finally, the influence of spatial resolution on the separability of the mineral phases is investigated.

Examples of polymetallic massive sulphide complexes, SEDEX deposits, REE deposits will be presented. All results are discussed in context of geology. The accuracy of mineral maps is assessed by validation data.