EXPLOITING 3D MULTISPECTRAL TEXTURE FOR A BETTER FEATURE IDENTIFICATION FOR CULTURAL HERITAGE

Abstract. 3D photogrammetric reconstruction and spectral imaging have already proven useful and are being used on a daily basis for studying cultural heritage. Dense Image Matching allows to create a virtual replica of the object that can be used for morphometric studies, for monitoring and conservation purposes, virtual access, reduced handling of fragile objects and share objects with a broad audience. 2D spectral imaging is used in the field of cultural heritage conservation to analyse the condition of an object, map a previous restoration, detect a change in composition, reveal sub-drawings, improve details, etc. A 2D image representation of a three-dimensional object is a limited field of view and lead frequently to a lack of information, especially for artifacts with complex geometries. The combination of both techniques is the next step toward a more complete and more objective record of an object, but it can also be a tool to improve the identification of details presents on artifacts. This study focuses on a methodology aiming to combine photogrammetry and spectral imagery acquired from a modified DSLR camera. Two case studies acquired with multispectral reconstruction techniques are analysed. They are used to demonstrate the advantages and disadvantages of the developed methodology. The obtained results show that spectral imaging reconstruction is highly related to used wavelengths. Infrared and ultraviolet fluorescence can enhance features identification of the objects that are not or less visible in classic white light photogrammetry. Combining 3D reconstruction and multispectral imagery can facilitate the readings and the understanding of the object. It can help conservator and researchers to better understand the objects and how to preserve them.