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Image based 3D Reconstruction in Cultural Heritage Preservation
Alessandro Cefalu, Mohammed Abdel-Wahab, Michael Peter, Konrad Wenzel and Dieter Fritsch
Institute for Photogrammetry, University of Stuttgart, Geschwister-Scholl-Straße 24D, Stuttgart, Germany
Keywords: 3D Reconstruction, Structure-from-Motion, Dense Image Matching, Cultural Heritage.
Abstract: Documentation of the current state of an object is often the first crucial step in cultural heritage
preservation. Especially for large scale objects as buildings this task becomes complex and time consuming.
Hence, there is a growing interest in new, more efficient techniques, which ease the process and reduce the
financial impact of surveying actions. In case of façade restoration, experts need to map damages and plan
the corresponding measures, before the actual restoration can take place. Here, two-dimensional CAD
drawings, depicting each single stone, serve as a basis. Traditionally these plans are derived from classical
surveying. Often a photogrammetric approach is chosen to reduce the efforts on site. But still image
processing, including image registration and point measurements, is carried out punctually and manually.
Since about three years, our institute supports the introduction of modern image processing tool chains to
the application field of heritage preservation. Recently we participated in the restoration of the tower
facades of the St. Martin dome in Rottenburg/Neckar, Germany. We combined laser scans, terrestrial
imagery and images captured from a UAV platform, incorporating structure-from-motion, dense image
matching, point cloud registration and production of orthographic projections, from which the CAD
drawings could be derived.
1 INTRODUCTION
Cultural heritage preservation has come to more
attention in the last years, as there is a growing
awareness of the need to maintain monuments and
other artefacts for future generations. As an initial
step most preservation actions include a
documentation of the current state of the object of
interest. In case of façade restoration actions,
standard surveying methods are usually chosen to
observe the façade’s geometric appearance. Enough
points need to be measured to allow a mapping of
each single stone and other details important for the
restoration task. From these measurements 2D CAD
drawings are derived, which again enable civil or
structural engineers and architects to map damages,
plan corresponding counter measures and estimate
costs.
Tachymetry as a classical surveying method
provides very accurate but only punctual
measurements which need to be triggered manually.
Thus laser scanning is often preferred due to its’
high measurement density and fast acquisition rate.
Photogrammetry also provides fast on-site
acquisition. When used in a modern, highly
automated manner, incorporating techniques as
structure-from-motion and dense image matching, it
can provide results comparable to laser scanning to a
much lower price of hardware.
Certainly, it has the drawback of being a
triangulating measurement technique and thus a
point in space must be observed from more than one
station, but a camera station can be changed without
much effort. In fact the camera can be mounted on a
moving platform as a crane or a hoisting platform
and reach areas of a building which are not
accessible from the ground. Due to its’ relatively
low weight it can also be carried by small UAVs,
improving the approach’s flexibility even more.
Since both, laser scanning and dense image
matching, observe arbitrary points in space with a
high density, producing orthographic projections
(orthophotos) of the data seems an adequate basis
for the final CAD drawings.
Our institute promotes the introduction of
modern image processing strategies into the branch
of heritage preservation through practical application
of internal and external developments since more
than three years. Within the presented project, which
aims at the restoration of the facades of the St.
Martin dome in Rottenburg am Neckar, Germany,
we took over the task of status-quo-documentation.
201
Cefalu A., Abdel-Wahab M., Peter M., Wenzel K. and Fritsch D..
Image based 3D Reconstruction in Cultural Heritage Preservation.
DOI: 10.5220/0004475302010205
In Proceedings of the 10th International Conference on Informatics in Control, Automation and Robotics (ICINCO-2013), pages 201-205
ISBN: 978-989-8565-70-9
Copyright
c
2013 SCITEPRESS (Science and Technology Publications, Lda.)