The digital anastylosis and the semantic segmentation: the case of the Magna Graecia masks in the Mediterranean area

Fifty years of archaeological activities carried out in the Aeolian Islands have made it possible to bring to light the most complete collection of theatrical masks of the ancient world, an important testimony of the material culture of the theatrical world, during the Classical era. The theatrical masks, preserved at the ‘L. Bernabò Brea’ of Lipari, may be schematized, from a morphological point of view, in three distinct degrees: ‘whole masks’, whole fragments and ‘mute’ fragments. The digital reconstruction and anastylosis workflow follow the same breakdown of these three degrees of status: they have been developed through an inverted pyramid trend, in a scalar and hierarchical way. The universality of the method makes it repeatable and universally applicable to other archaeological finds belonging to a proto-industrial and serial artisan production.
The research aims to define a series of methodologies and techniques to be adopted for the direct survey of archaeological artefacts in fragments and for the definition of a reconstruction and digital anastylosis protocol, with the aim to restore a new memory to the so-called ‘mute’ finds. In order to clarify the genealogical and filiation relationships between the masks, a geometric grid of conspicuous points was identified on each digital model which allowed to rearrange the finds on the basis of their dimensional relationships and to advance, at the same time, a parallel hypothesis of segmentation and semantic annotation, it experimenting the most modern and innovative semantic annotation practices for the Cultural Heritage, in order to improve the understanding, the cataloging and enhancement of the historical data.

Versioning Virtual Reconstruction Hypotheses: Revealing Counterfactual Trajectories of the Fallen Voussoirs of Notre-Dame de Paris using Reasoning and 2D/3D Visualization

Virtual reconstruction should move beyond merely presenting 3D models by documenting the scientific context and reasoning underlying the reconstruction process. For instance, the collapsed arch in the nave of Notre-Dame de Paris serves as a case study to make explicit the reconstruction argumentation encapsulated in relation to the spatial configuration of the arch and the voussoirs. The experiment is twofold: (1) setting up of the 3D dataset where the hypotheses are modeled as versions using logic programming, and (2) evaluating the scientific narrative of reconstruction through both a custom 2D-3D visualization and competency questions on the enriched 3D data. Formalization, reasoning, and visualization are combined to explore the nonlinear scientific hypotheses and narrative of the reconstruction. The results explicitly show both the factual information on the physical and digital objects, as well as the counterfactual propositions allowing the reasoning at play in the reconstruction. The hypotheses are visualized as counterfactual trajectories creating an open dynamic visualization that makes possible the spatialized querying of conflicting interpretations and embedded memory in place.