Photogrammetry

lundi 29 Mar 2021

Photogrammetry is a low-tech technique that can be used to create a precise 3D rendering of an artefact without having to resort to traditional molding techniques. It is of particular interest for very delicate structures that cannot be handled during the process. Objects of all sizes can be treated. The resulting 3D model can be used for the off-location study of the artefact, for establishing condition reports, for monitoring surface alterations, for creating adapted supporting structures for storage and transport as well as the recreation of missing parts.

Equally of interest is the exact rendering of the surface topography that can be viewed with or without colour, allowing a greater precision when assessing surface textures. UV and infra-red images can be integrated in a second step and superposed on the existing surface topography.

For the DOA project the aim was to carefully document the initial condition of the cartonnage case before any intervention was made. This was done in order to document possible changes during transport or handling and to permit a high resolution restitution of the complex surface for an initial condition report. For that 800 high-resolution photographs were taken from various angles by Andreas Hochuli (HKB). These were uploaded to the Metashape (Agisoft) software that reconstructed each photograph, transforming them into scaled models with approximately 120 million surface points. The result is a high-precision virtual model that can be examined from all sides and allows to zoom into areas of particular interest.

The technique will also be used at the end of the project when an adapted supporting structure will have to be made for the upper cartonnage case.

Visualisations will be uploaded soon