|
In Poland there are some technical instructions that determine rules of creating architectonic documentation. For example, a kind of information about a real object condition and other data necessary for further design works, etc. Very often, on the basis of photogrammetric products (like orthophoto) vectorial sketches are created. As we know, this process is very time-consuming, especially when the historic building has a lot of detail. The main problem here is generating a correct 3D model of the structure. Research has been conducted on the Saint Anna Church in Warsaw. The work was divided into two stages: measurements of the nave vaulting and the church façade. When working with the barrel vaulting, the primary image transformation was conducted using the DLT (Direct Linear Transformation ) method. A second approach was based on terratriangulation of image stereopairs and creating a Digital Surface Model by means of two methods: one based on oriented stereopairs and the other by using a point cloud acquired with a laser scanner. Orthoimages were then generated using both models. The church façade was measured in a similar way, using the Digital Surface Model obtained with both methods. On the basis of our research we can say that practically there is no possibility to automatically generate accurate and correct 3D models of historic buildings (because of their complex shapes and dimensions). Semi-automatic methods require more time. Using 3D models from terrestrial laser scanning data (point clouds) enables significant time efficiency and generation of correct orthophotos.
|