Ercolano. Documentare e studiare siti archeologici storici: Il contributo delle tecnologie digitali

n the last few years, the use of 3D reality-based techniques in Cultural Heritage has grown significantly. Laser scanner and aerial or close-range photogrammetry have become the new tools for many experts and professionals in the field of documentation and restoration. As it is fundamental to integrate old and new datasets, a common topographical framework is frequently required to guarantee the perfect fusion of data originating from different sensors or acquired in different periods. Integrating the scans with high-resolution images allows to document and evaluate the state of art and conservation of archaeological structures quickly. New methods and approaches are tested to check the reliability and accuracy of the 3D objects, particularly if these digital replicas are the final product of the alignment of separate data-acquisition campaigns (4D). The paper deals with the implementation of a network for the Insula III of Herculaneum, an area greater than 4.000 sqm, since 2005 main case-study of the second research projet of the University of Bologna in Vesuvian region, the Domus Herculanensis Rationes (DHER). The topographical grid, obtained through the alignment and roto-translation of over than 300 scans, has been used to geo-reference and scale the high-resolution images taken during a parallel photogrammetric campaign of the painted and decorated walls of the Insula, in the framework of the Atlante degli Apparati Decorativi di Ercolano, a complete photogrammetric and graphic catalogue of the wall paintings and decorated floors of Herculaneum. The contribution deals with the workflow making the documentary basis of a research on decorations in context (as part of a research in household archaeology, insula based) and mainly on the tests carried out to evaluate the accuracy of the network.