Hyperspectral Imaging Techniques for the Study, Conservation and Management of Rock Art

Abstract

Featured Application: This work presents several hyperspectral techniques that can provide a scientific and non-destructive method for the study, conservation and management of rock art. Tasks such as recognition of coloring matter, formal recognition of the figures, superposition of forms and documentation of the state of conservation can be solved efficiently with hyperspectral imaging.Abstract: Paleolithic rock art is one of the most important cultural phenomena in the history of mankind. It was made by making incisions and/or applying natural pigments mixed with water or organic elements on a rock surface, which for millennia has been subjected to different factors of natural and anthropogenic alteration that have caused its deterioration and/or disappearance. The present paper shows a methodology that employs hyperspectral technology in the range of visible light and the near infrared spectrum, providing a scientific and non-destructive way to study, conserve and manage such a valuable cultural heritage. Recognition of coloring matter, formal recognition of the figures, superposition of forms and documentation of the state of conservation are relevant topics in rock art, and hyperspectral imaging technology is an efficient way to study them. The aim is to establish a method of creating pigment cartography and enhancing the visualization of rock art panels. Illumination sources, spectroradiometry measurements and camera adjustments must be taken into account to generate accurate results that later will be pre-processed to derive reflectance data, and then pigment analysis and enhanced visualization methods are applied. This methodology has allowed us to obtain 76% more figures than using traditional techniques throughout the case study area.The deteriorating factors can act in an isolated or combined way on this cultural heritage and its support, and include dirt, impacts, flaking, disintegration, washing, glazes, coatings, etc.The conservation of industrial, technical and cultural heritage requires a deep understanding of the significance and complexity of a place. Good conservation of our heritage is based on informed decisions, and good documentation ensures that knowledge of heritage places will be passed on to future generations.This work analyses, develops and implements a methodology to generate information not visible to the naked eye due to dirt, washing, glazes and coatings. This information not only improves the visualization of the panels, but also helps us to understand how they were created and sheds light on the stratigraphy or sequence of the execution of different motifs.The methodology is applicable to any rock art panels, and any cultural or industrial heritage objects in general, that need to be studied or controlled in time. The method has been tested on a panel that has been studied since the beginning of the 20th century, which presents a series of complex cases to solve such as superposition of paints, calcite glazes, pigment-sketch combination, etc.Traditional rock art documentation s...

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