Multiple Optical Sensor Fusion for Mineral Mapping of Core Samples

Sensors (Basel). 2020 Jul 5;20(13):3766. doi: 10.3390/s20133766.


Geological objects are characterized by a high complexity inherent to a strong compositional variability at all scales and usually unclear class boundaries. Therefore, dedicated processing schemes are required for the analysis of such data for mineralogical mapping. On the other hand, the variety of optical sensing technology reveals different data attributes and therefore multi-sensor approaches are adapted to solve such complicated mapping problems. In this paper, we devise an adapted multi-optical sensor fusion (MOSFus) workflow which takes the geological characteristics into account. The proposed processing chain exhaustively covers all relevant stages, including data acquisition, preprocessing, feature fusion, and mineralogical mapping. The concept includes (i) a spatial feature extraction based on morphological profiles on RGB data with high spatial resolution, (ii) a specific noise reduction applied on the hyperspectral data that assumes mixed sparse and Gaussian contamination, and (iii) a subsequent dimensionality reduction using a sparse and smooth low rank analysis. The feature extraction approach allows one to fuse heterogeneous data at variable resolutions, scales, and spectral ranges and improve classification substantially. The last step of the approach, an SVM classifier, is robust to unbalanced and sparse training sets and is particularly efficient with complex imaging data. We evaluate the performance of the procedure with two different multi-optical sensor datasets. The results demonstrate the superiority of this dedicated approach over common strategies.

Keywords: data fusion; dimensionality reduction; feature extraction; hyperspectral; hyperspectral mixed sparse and Gaussian noise reduction (HyMiNoR); mineral exploration; multi-sensor data; optical sensor; orthogonal total variation component analysis (OTVCA); sparse and smooth low-rank analysis (SSLRA); spectral imaging; support vector machine (SVM).