6182
eng
reportzib
0
--
2017-01-25
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Revealing hidden text in rolled and folded papyri
Ancient Egyptian papyri are often folded, rolled up or kept as small packages, sometimes even sealed. Physically unrolling or unfolding these packages might severely damage them. We demonstrate a way to get access to the hidden script without physical unfolding by employing computed tomography and mathematical algorithms for virtual unrolling and unfolding. Our algorithmic approaches are combined with manual interaction. This provides the necessary flexibility to enable the unfolding of even complicated and partly damaged papyrus packages. In addition, it allows us to cope with challenges posed by the structure of ancient papyrus, which is rather irregular, compared to other writing substrates like metallic foils or parchment. Unfolding of packages is done in two stages. In the first stage, we virtually invert the physical folding process step by step until the partially unfolded package is topologically equivalent to a scroll or a papyrus sheet folded only along one fold line. To minimize distortions at this stage, we apply the method of moving least squares. In the second stage, the papyrus is simply flattened, which requires the definition of a medial surface. We have applied our software framework to several papyri. In this work, we present the results of applying our approaches to mockup papyri that were either rolled or folded along perpendicular fold lines. In the case of the folded papyrus, our approach represents the first attempt to address the unfolding of such complicated folds.
1438-0064
urn:nbn:de:0297-zib-61826
10.1007/s00339-017-0808-6
Appeared in: Applied Physics A 123 (2017) pp. 171
Daniel Baum
Daniel Baum
Norbert Lindow
Hans-Christian Hege
Verena Lepper
Tzulia Siopi
Frank Kutz
Kristin Mahlow
Heinz-Eberhard Mahnke
ZIB-Report
17-02
eng
uncontrolled
unfolding, papyri, computed tomography
Computer Applications
INTERDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY
COMPUTER SCIENCE (For papers involving machine computations and programs in a specific mathematical area, see Section -04 in that area)
Visual Data Analysis
Baum, Daniel
Hege, Hans-Christian
Lindow, Norbert
no-project
https://opus4.kobv.de/opus4-zib/files/6182/ZR-17-02.pdf
6179
2017
2017
eng
171
3
123
article
0
2017-02-17
2017-02-17
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Revealing hidden text in rolled and folded papyri
Ancient Egyptian papyri are often folded, rolled up or kept as small packages, sometimes even sealed. Physically unrolling or unfolding these packages might severely damage them. We demonstrate a way to get access to the hidden script without physical unfolding by employing computed tomography and mathematical algorithms for virtual unrolling and unfolding. Our algorithmic approaches are combined with manual interaction. This provides the necessary flexibility to enable the unfolding of even complicated and partly damaged papyrus packages. In addition, it allows us to cope with challenges posed by the structure of ancient papyrus, which is rather irregular, compared to other writing substrates like metallic foils or parchment. Unfolding of packages is done in two stages. In the first stage, we virtually invert the physical folding process step by step until the partially unfolded package is topologically equivalent to a scroll or a papyrus sheet folded only along one fold line. To minimize distortions at this stage, we apply the method of moving least squares. In the second stage, the papyrus is simply flattened, which requires the definition of a medial surface. We have applied our software framework to several papyri. In this work, we present the results of applying our approaches to mockup papyri that were either rolled or folded along perpendicular fold lines. In the case of the folded papyrus, our approach represents the first attempt to address the unfolding of such complicated folds.
Applied Physics A
10.1007/s00339-017-0808-6
yes
urn:nbn:de:0297-zib-61826
Daniel Baum
Daniel Baum
Norbert Lindow
Hans-Christian Hege
Verena Lepper
Tzulia Siopi
Frank Kutz
Kristin Mahlow
Heinz-Eberhard Mahnke
Visual Data Analysis
Visual Data Analysis in Science and Engineering
Image Analysis in Biology and Materials Science
Baum, Daniel
Hege, Hans-Christian
Lindow, Norbert
PAPYRUS
Zuse Institute Berlin (ZIB)
6416
2014
eng
conferenceobject
0
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The Potential of Surface-based Geometric Morphometrics for Evolutionary Studies: An Example using Dwarf Snakes (Eirenis)
Geometric morphometrics plays an important role in evolutionary studies. The state-of-the-art in this field are landmark-based methods. Since the landmarks usually need to be placed manually, only a limited number of landmarks are generally used to represent the shape of an anatomical structure. As a result, shape characteristics that cannot be properly represented by small sets of landmarks are disregarded.
In this study, we present a method that is free of this limitation. The method takes into account the whole shape of an anatomical structure, which is represented as a surface, hence the term ‘surface-based morphometrics’. Correspondence between two surfaces is established by defining a partitioning of the surfaces into homologous surface patches. The first step for the generation of a surface partitioning is to place landmarks on the surface. Subsequently, the landmarks are connected by curves lying on the surface. The curves, called ‘surface paths’, might either follow specific anatomical features or they can be geodesics, that is, shortest paths on the surface. One important requirement, however, is that the resulting surface path networks are topologically equivalent across all surfaces. Once the surface path networks have been defined, the surfaces are decomposed into patches according to the path networks.
This approach has several advantages. One of them is that we can discretize the surface by as many points as desired. Thus, even fine shape details can be resolved if this is of interest for the study. Since a point discretization is used, another advantage is that well-established analysis methods for landmark-based morphometrics can be utilized. Finally, the shapes can be easily morphed into one another, thereby greatly supporting the understanding of shape changes across all considered specimens.
To show the potential of the described method for evolutionary studies of biological specimens, we applied the method to the para-basisphenoid complex of the snake genus Eirenis. By using this anatomical structure as example, we present all the steps that are necessary for surface-based morphometrics, including the segmentation of the para-basisphenoid complex from micro-CT data sets. We also show some first results using statistical analysis as well as classification methods based on the presented technique.
Abstract in DigitalSpecimen 2014
no
Daniel Baum
Daniel Baum
Kristin Mahlow
Hans Lamecker
Stefan Zachow
Johannes Müller
Hans-Christian Hege
Visual Data Analysis
Baum, Daniel
Hege, Hans-Christian
Lamecker, Hans
Zachow, Stefan
SNAKE-BONES