Photogrammetry of Mural Reliefs: 3D Digitization of Heritage

The digitization of mural reliefs represents one of the most rewarding challenges in digital archaeology. Unlike standalone objects, a relief requires capturing subtle variations in depth on a flat surface. This article details the technical workflow for obtaining high-fidelity three-dimensional models, from photographic capture in the field to the generation of optimized meshes for conservation, virtual restoration, and interactive dissemination.

Technical Workflow: Capture, Processing, and Texturing 🛠️

The process begins with a controlled photographic capture session. A DSLR camera with a fixed 50mm lens is recommended to avoid distortions. Lighting should be cross and diffuse to minimize harsh shadows that hide bas-relief details. Photographs are taken with 80% overlap between shots, both horizontally and vertically. Reconstruction software, such as Metashape or RealityCapture, processes these images through pixel correlation. The result is a dense point cloud that is transformed into a polygonal mesh. Final texturing requires projecting the original images onto the mesh, correcting exposure for a uniform finish that faithfully reflects the original polychromy of the mural.

Applications in Conservation and Interactive Dissemination 🌍

An accurate 3D model allows restorers to measure micro-cracks and plan interventions without touching the physical piece. For dissemination, these digitized reliefs are integrated into virtual reality environments, allowing the public to observe details from angles impossible during an in-person visit. The democratization of access to heritage, where a fragile relief can be explored by thousands of people without risk of deterioration, fully justifies the technical investment in this workflow.

What controlled lighting techniques allow for more precise capture of micro-reliefs on worn mural surfaces without damaging the heritage?

(PS: and remember: if you can't find a bone, you can always model it yourself)