Textured 3D measurements of Celtic small bronze sculptures in the context of the special exhibition "The Imagery of the Celts"
In the course of this special exhibition “The World of Images of the Celts”, small Celtic sculptures made of bronze were recorded using high-precision optical 3D measurement technology in combination with high-resolution RGB color images. The background to the measurement activity is that this data can continue to be exhibited as a 3D print or virtual model at the locations of the special exhibition after the end of the renovation work in the area of the Archaeological State Collection.
In the Hallstatt period (“Early Celtic Period”), which was rather hostile to images, living beings were only represented in a highly stylized way, if at all. Geometric patterns with straight lines predominate in art. This changed with the beginning of the La Tène period in the 5th century BC. BC north of the Alps fundamentally. Based on suggestions from the Mediterranean and the Middle East, an independent Celtic art style with new content is created. Ornaments are now based on floral motifs and the stroke of a compass, humans and animals form fantastic hybrids, sculptures are becoming increasingly more realistic and individual.
The renovation of the Archaeological State Collection, which is expected to last until the end of 2020, offers the rare opportunity to present all the finds on this topic that have been shown in the Munich permanent exhibition at other locations. The planned special exhibition includes a total of around one hundred “masterpieces” with depictions of people, animals and symbols. Ceramics, jewellery, everyday objects, coins and figurative art from the late Hallstatt period to the beginning of the Roman period will be on display under the working title “The pictorial world of the Celts”. (Source: Dr M Will)
In the course of this special exhibition, i3mainz recorded small Celtic bronze sculptures using high-precision optical 3D measurement technology in combination with high-resolution RGB color images. The background to the measurement activity was the desire to continue showing the scanned artefacts as 3D prints or virtual models at the locations of the special exhibition after the completion of the renovation work in the Archaeological State Collection.
The three-dimensional digitization of the finds was carried out with a structured light scanner (ATOS Triple Scan), as it is very flexible with regard to the required 3D resolutions and works in a high accuracy range. 3D data alone is not sufficient for such a type of evaluation, as it does not provide the complete range of information about the object to ensure complete coverage of the visible spectrum. For this reason, a photogrammetric multi-image association was also created, which, in addition to the 3D data, also provides detailed color information. The challenge of the 3D and color capture lay in the dimensions (3cm³ - 12cm³) and surface quality (dark, shiny) of the individual objects. The selected 3D resolution of the measuring system was 50 µm with a measuring volume of 170 mm³. The spatial resolution of the image group for texturing the 3D data was around 30 µm and is therefore somewhat higher resolution than the 3D data.
Based on the measurements, high-resolution and textured 3D models were derived from 14 objects, which can be used in different ways. On the one hand they are to be used for the planned media or museum preparation and on the other hand it is planned to present physical 3D copies as exhibits in cooperating museums. A web-based application for providing the data is also conceivable here, although discussions are still ongoing with the State Archaeological Collection.