Digitisation of cultural heritage
Chapter 2: Merging sensors for the best results
Merging sensors for the best results
While collecting the data, the most modern technologies and sensors were used. The laser scan data was collected with the Leica ScanStation P20. The Aibotix Aibot X6 UAV was used to digitise big buildings and areas, as well as hard-to-reach areas, like steeples, roofs and facades.
With the TLS, digital pictures of objects and buildings with a high metrical accuracy can be captured in the shortest time.
A challenge of the production of 3D models from TLS data, though, is that in spite of the high point density, small details of the architectural elements cannot be shown according to the demands when the distance is great between the laser scanner and the object.
To reach the demanded detail, TLS and photogrammetric data are brought together in later steps. To obtain the detail needed in the project and to digitise far-away objects, TLS data needed to be combined with photogrammetry.
The advantages with photogrammetry are the accessible degree in details and the realistic reproduction of the colours.
On the other hand, a disadvantage from the photogrammetry is that the model can be distorted or deformed during the reconstruction.
In this project, two different methods of photogrammetry were used:
- Robotic imaging with a tripod - the camera is mounted on a programmable robotics panorama tripod.
- Handheld image – the camera is used without a tripod
The best results are reached from a combination of both photogrammetric methods.