Seeing the past in a new light: LED multi-spectral imaging as an interpretative aid for archaeological excavation

Archaeologists identify stratigraphic events and distinguish between material and using visual and textural contrasts. However, relying purely on the visible spectrum means that salient information may be overlooked and ultimately lost. Recent development in multispectral imaging has the potential to improve our ability to detect these contrasts.In this work we built and tested a novel, fast and inexpensive LED multispectral illumination imaging system to improve contrast between different stratigraphic interfaces and identify material for sampling for further scientific analyses. The prototype achieves this using 16 discrete LED illumination wavelengths spanning the near ultraviolet, visible and near infrared regions of the electromagnetic spectrum, with the goal of performing preliminary spectral analyses in near real time. We demonstrate the utility of this method using sample images to show that we can improve our ability to distinguish stratigraphic interfaces, identify material that the detection of fluorescent materials is achievable without the use of costly optical filtration. This will enable archaeologists to make better informed decisions in the field while excavation is ongoing.