Investigation and application of image-based geometric documentation methods in archaeology
Efficient documentation of three-dimensional objects and findings is a common task in archaeological contexts. The timely and rapid documentation of a situation is a task that has to be carried out regularly on excavations or accompanying uncovering or restoration processes. In the case of geometrically more complex findings in particular, a three-dimensional image is necessary or at least very desirable.
Special systems such as 3D scanners are expensive and usually require specially qualified personnel. They are therefore rarely available. The use of new calculation methods and processes using ‘simple’ images or image series is a promising approach to simplify this documentation work. What is important here is a high level of reliability of the processes and good integration into the existing processes.
Various projects with different tasks were selected for the investigations and tests.
During the work to uncover a block salvage in the restoration workshops of the RGZM, a total of eight different states were recorded by the restorer. The recordings were made with a single-lens reflex camera, the calculations using free software. After orienting and referencing the data, the individual states can be visualized and analyzed as point clouds. They allow the uncovering process to be tracked and measurements to be taken of the positions in the block. The simple integration of views such as ortho images or height models in the graphic documentation of the object parts is currently still part of the investigations.
The condition at the end of the excavation work on a Neolithic settlement in the Taunus was recorded with a photo association. The excavation area itself could thus be recorded well. The processing of data from the environment was less successful. Due to the location in the forest with some small, moving vegetation (e.g. leaves in the wind), problems and larger gaps arose here. It is planned to take another picture of the surrounding area with the remains of a wall in winter when the trees and bushes are free of leaves.
On an excavation of an early Upper Palaeolithic settlement site carried out by the RGZM, the method was tested in comparison to 3D laser scanning for selected sections. The relatively simple creation of elevation models and ortho images as well as the problem-free adaptation of the method to different scales and object sizes are very promising. Based on the results, the optimization and integration of the 3D recordings in the excavation processes for the upcoming work is in the foreground.