New ways to extract archaeological information from hyperspectral pixels

Airborne remote sensing for archaeology is the discipline that encompasses the study of archaeological remains using data collected from an airborne platform by means of digital or film-based aerial photography, airborne laser scanning, hyperspectral imaging etc. So far, airborne hyperspectral scanning or – more accurately – airborne imaging spectroscopy (AIS) has occupied only a very small niche in the field of archaeological remote sensing: besides reasons of cost, the common archaeologically-insufficient ground-sampling distance can be considered the main limiting factor. Moreover, the technical processing of these data sets with a high level of potential redundancy needs specialized software. Typically, calculation of band ratios and a principal component analysis are applied. As a result, the few practical applications of archaeological AIS have not been entirely convincing so far. The aim of this paper is to present new approaches for analysing archaeological AIS data. The imagery under study has a ground-sampling distance of 40 cm and covers the Roman town of Carnuntum (Austria). Using two algorithms embedded in a specifically developed MATLAB® toolbox, it will be shown how the extracted archaeological information can be enhanced from high-resolution hyperspectral images. A comparison with simultaneously acquired vertical photographs will indicate the specific advantages of high-resolution AIS data and the gain one can obtain when exploiting its potential using any of the newly presented methods.