Praca Dyplomowa - Photogrammetry and Remote Sensing - AGH

SUMMARY
Sculptures and other artifacts are exposed to damages and it is hard to avoid them. For
cultural heritage preservation new replicas of these objects should be done. For this purpose
the best solution is to use non-touching methods, like photogrammetry and three-dimensional
scanning, which will not do any harm to the object. Then 3D digital model may be used and
by applying of 3D printers the real copy may be done
The purpose of the report was to investigate methods on making detailed digital models on
example of a sculpture from Nidaros Cathedral. The goal was to get as accurate – detailed
model as possible. There is comparison on photogrammetric, 3D scanning methods and
available 3D modelling tools.
To make a very detailed digital model of round, complex, and small objects – very big point
cloud is needed. The point cloud has to be accurate with high resolution. To make such a
point cloud from images any software needs a lot of time for computation. Also, computation
of big amount of points in the data from scanning takes a lot of time. This is not because of
low PC, but because of software limitations. Some scanners are able to make more dense
point cloud with better accuracy than others. With higher resolution and better accuracy
scanners become smaller, and also distance range is decreasing. Though, for small object
smaller distance is required. Photogrammetry may produce also very good results, if only the
material is non-reflective/shiny, or glass.
In the project photogrammetric software has been used, such as PhotoModeler Scanner and
Topcon ImageMaster, where both are able to create 3D surface from photographs, taken by
non-metric camera. Both softwares provide camera calibration. The results at the end were
quite good, but the sculpture is quite shiny and reflects the light, and this situation is not
required for image matching and creating 3D points. Therefore, the model results with a lot of
noise. Also, the time needed for DSM creating was very long and this part still needs some
improvement. Free software from Autodesk – Project Photofly 2.0 was also tested. The
application creates mesh and may be used by non-experienced users. Nevertheless, the results
are not so accurate or the resolution is lower, it still may be used in most common situations.
From laser scanning, Konica Minolta VI-910 was used for data acquisition, but also very
interesting handheld small scanner from Artec was used. Both are created for small range
distances; nevertheless Artec seems to be better for smaller objects. It has better accuracy and
higher resolution. In both cases, softwares recommended by the companies were used for
modelling. Geomagic software was also used for post processing afterwards. Polygon Editing
Tool from Konica Minolta seemed not working properly with new Windows 7 x64 bits, but
Artec was even able to use most of the processors cores for computations.
The best model was achieved by applying small structured scanner from Artec with 0,5mm of
resolution and accuracy up to 0,1mm. The model created using Artec software works good,
but in the author‟s opinion Geomagic software works better, where smoothing may be done in
the respect to curves.
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