Martin SCHAICH / Dominik WESTERMANN
(ArcTron 3D, Altenthan, Germany)
Outline: Many archaeologists have found themselves struggling with the following problem: a complex archaeological record is uncovered and calls for a three dimensional documentation. But time constraints and limited budgets are the main obstacles to get a 3D model which is important for future scientific work. Photographs and 2D-drawings with some written descriptions remain the only documentation of the site and findings. Heritage preservation specialists, architectural historians and conservators are facing similar problems when trying to accomplish as-built surveying under time pressure. A 3D model would facilitate the scientific work on many levels. But how can one get a 3D scanner with just limited funds, or a 3D surveying service provider right away on the spot?
Abstract: Creating 3D models – using just a digital camera and a particular software combination
With a series of digital photographs, a precise 3D point cloud of an object can be generated. It takes just a few steps using a special software bundle with Multiview-Stereo-Tools and the software aSPECT3D. What is needed is a standard digital SLR photo camera. After documenting the object with a large number of photographs from different angles, a 3D point cloud of the object is calculated.
The 3D point cloud is then being scaled and transformed into the desired coordinate system using aSPECT3D. This 3D model can then be combined and correlated with the data from other measurement systems (e.g. simple distance measurements, total station surveys, GPS, 3D laser scanners, 3D structured light scanners, etc.). Subsequently the user creates a triangular mesh and textures the recorded objects. The user can also produce sections, orthophotos etc. With some of the modelling and analysing features of aSPECT3D.
How to manage comprehensive 3D surveying data?
aSPECT3D includes a radically redesigned postgreSQL database. It allows structuring and managing all kinds of data like geometries, textures, points, metadata. The database can be customized and modified depending on the tasks. Expandable “templates” are tailored to the particular needs for archaeological excavations, architectural heritage and restoration documents. 3D data sets, which are imported into the database, can be further divided and classified. This allows the user to organize records and metadata in the forms of PDFs, movies, text and image files, etc.
aSPECT3D is a software program that generates textured 3D models, geometry and metadata.
Combined data from different measurement systems are processed and managed in a database which can be configured individually. This opens up new possibilities to science to generate and work with 3D information at relatively low cost.
But the levels of accuracy with this technology have still their limits. Therefore we see this system as a useful extension to laserscanning methods. For achieving very high resolution levels it is necessary to use a 3D laser scanner.
“Real 3D” as-built documentation in archaeology and conservation is likely to be established as common practice in the near future.
The talk would like to explain the process of 3D documentation with aSPECT3D and will show alternative and complementary ways to modern 3D-surveying methods.