A mobile Augmented Reality system integrating 3D model and radiance scaling to enhance epigraphical inscriptions

Samanta GREGGIO | Giuseppe SALEMI
(University of Padua, Department of Cultural Heritage, Padua, Italy)

Keywords: Augmented Reality, 3D Digital Model, Epigraphical Inscriptions, Radiance Scaling

Abstract:
Traditional survey techniques are, very often, “not enough” to analyse and valorize epigraphical finds when bad state of preservation, incision on irregular surface, dimension and shape, arrangement in museum are important factors that must be taken in account.
The innovative approach exploit widespread of mobile devices and it integrates 3D textured models and more techniques of scientific visualization in Augmented Reality systems. The main goal is the study of epigraphical inscriptions and dissemination of the semantic value, through virtual connections among artefacts, also preserved in different museum and institutions.
The test cases are 5 epigraphical inscriptions, on 3 boundary stones, dated from the 2nd century BC to the 1st century BC. They marked the border between Padova and Este (Italy) by putting the Euganean thermal area in Padova territory that takes advantage of natural resources.
The 3D textured models are derived by image based technique (Structure From Motion) and they provide accurate visualization. Then, other procedures are tested to select and group faces of 3D model that have the same morphological trend, like lambertian radiance scaling which highlights geometric detail by shading the concavities on the surface and enables to recognize heavily damaged letters. Finally, an interactive Augmented Reality system, running on mobile devices and using 2D markerless tracking, allows to load more digital contents on standard published images, like 3D textured models, rendering and video-rendering of radiance scaling. The system is also able to group epigraphical inscriptions according to chronology and palaeographic techniques.
The results give new scientific instrument to analyse epigraphical inscriptions, sharing data and collaborations among researchers located in different places, besides they enable to disseminate with intuitive and educative technologies the semantic value of artefacts, through augmentation of scientific and non-scientific publications and also in different contexts of valorization, like museum or open air installation.