Photogrammetry and macro photography. The experience of the MUSINT II project in the 3D digitization of small archaeological artifacts

The MUSINT II project was created to publicize and promote Minoan glyptic, a little-known archaeological heritage. Its contents were designed to involve both specialists and the general public (adults and children). The project focuses on the 3D digitalization of seventeen very small (ca. 15 mm diameter) seals, stored in the archives of the National Archaeological Museum of Florence. The digitalization of these artifacts required both a high-quality resolution technique capable of capturing their morphology and decorative motifs and also that the resulting 3D models were appealing to the target audience. For this reason, an approach based on Structure from Motion (SfM) photogrammetry was chosen. This technology makes it possible to obtain three-dimensional reproductions from photographs made by non-dedicated devices, but the tiny-object survey required specific instruments and skills in order to be scanned in such a way as to acquire a high quality and shadow-free texture. The macro photography technique was applied together with a specific workflow to obtain high quality photogrammetric models and to save time in acquiring and processing images. With this methodology, 3D models of high metric precision mesh and maximum color fidelity textures were obtained in the Agisoft Photoscan software. This process delivers results with high level detail for low costs and minimal acquisition and processing time (ca. four hours).