Multiband photogrammetry for multispectral 3D reconstruction of statuary

• Multi-band photogrammetry workflow for multi-spectral 3D reconstruction of ancient statuary. • Investigates original polychromy traces on ancient statuary with multi-spectral 3D imaging. • Integrated RGB, VIL, and UVL imaging captures pigment traces in 3D detail. • Non-invasive technique reveals previously hidden material details on sculptures. • Case study of the Bikini Venus statue demonstrates workflow efficacy. • Flexible workflow supports accurate digital preservation of fragile heritage artifacts. The aim of this work is to present an advancement in the technical protocol to obtain multiband 3D reconstructions of ancient statuary by photogrammetric acquisition of different input data as Visible (VIS), Ultraviolet Induced Visible Luminescence (UVL), and Visible Induced Luminescence (VIL). An acquisition workflow tailored for multiband photogrammetry was developed and tested on the Venus in a Bikini (INV 152798), belonging to MANN collection. The Bikini statue preserves rich remnants of the original polychromy, and in particular gilding on the strophyon (a sort of swimming suit) and on the sandals and pink traces on the tree trunk support and the draped cloak. The workflow, in comparison to others, is designed to generate multiband 3D reconstructions while remaining flexible and applicable in diverse operational scenarios. The final multispectral 3D model, integrated into a Web3D framework (ATON), allows for interactive visualization, facilitating both scientific research and digital dissemination. It allows to simultaneously explore morphological characteristics on the entire sculpture at high resolution, combining detailed information on those properties not visible to the naked eye, but revealed by the multiband acquisitions. The extrapolated observations relate mainly to the presence on the surface of conservative intervention, or peculiar pigments and pattern decoration that can be highlighted.