Spectral imaging of medieval artifacts: collection, calibration, and analysis

Multispectral and hyperspectral imagery have been used in the remote sensing community for over 30 years, with advances in both instrumentation and analysis algorithms producing significant improvements in capabilities and the breadth of applications. These systems have largely been deployed on manned aircraft and satellites, and now are commonly operated on small Unmanned Aerial Vehicles (UAVs). Recently, with the miniaturization of these systems (and corresponding decrease in cost), they are being deployed in laboratory settings for a wide range of sensing problems. Here, we use both multispectral (MSI) and hyperspectral imaging (HSI) to shed light on cultural heritage artifacts - manuscripts, artwork, maps, and other objects of historical and cultural significance. Multispectral imaging systems are generally used for more qualitative work - particularly enhancing features on artifacts, such as faded or erased text, that are not visible to the naked eye. On the other hand, HSI systems produce data that can be more quantitatively exploited, extracting information about the chemistry of pigments, inks, substrates, and other materials used in the creation of the objects. This information helps historians to understand the object's codicology, knowledge of how the object was made and potentially modified. Here, I will present a brief overview of the systems being used, as well as show some results for both MSI and HSI systems on medieval maps and manuscripts imaged at Durham University, the Bodleian Library (Univ. of Oxford), as well as other institutions around the world.