LEDs let archaeologists see the past in a new light
An archaeological excavation is a little like eating a layered cake: Once you have removed a layer, you cannot put it back. The problem becomes even trickier if two layers look almost exactly the same. Researchers from Aarhus University and Moesgaard Museum in Denmark have now developed a relatively inexpensive multispectral imaging system that gives archaeologists more ways of looking at the…
Archaeologists are uncovering new ways to explore ancient sites using innovative LED multispectral imaging technology. In a breakthrough study published in the Journal of Archaeological Science, researchers from Aarhus University and Moesgaard Museum in Denmark developed a relatively inexpensive system that employs LEDs at 16 different wavelengths, ranging from near-ultraviolet to near-infrared.
Unlike traditional white light illumination, this multispectral approach allows materials to absorb and reflect light differently, highlighting variations that are invisible to the naked eye. At an Iron Age site in Denmark known as Sorte Muld, the researchers tested the prototype and discovered that the LED system revealed hidden layers and changes in the soil that would have otherwise gone unnoticed.
The system's ability to detect subtle differences in material composition is particularly useful for identifying old ground surfaces, breaks in activity, and distinguishing between seemingly separate layers of soil. By illuminating the site with ultraviolet light, the researchers also found that small bone fragments fluoresced, making them easier to distinguish from surrounding soil. This feature could help archaeologists locate valuable material for scientific analysis, such as ancient DNA and protein studies.
The LED multispectral imaging system (LEDMSI) has distinct advantages over previous hyperspectral imaging technologies, being roughly 20 times cheaper. A second-generation prototype has already been tested at Fredbjerg, where archaeologists are excavating a cemetery from the late Viking Age and early Christian period. The new version can capture images in around 30 seconds, a significant improvement over the previous five-minute process.
The researchers are now working on refining the system, aiming to process the results onsite almost immediately, either on a computer or even a field device. Additionally, they hope to incorporate machine-learning software to help archaeologists identify different materials based on their spectral signatures. While the system is not expected to replace the trained archaeological eye, it seeks to provide valuable assistance in uncovering the rich history buried beneath layers of time.
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