TY - CHAP A1 - Arlt, Tobias A1 - Lindow, Norbert A1 - Baum, Daniel A1 - Hilger, Andre A1 - Mahnke, Ingo A1 - Hege, Hans-Christian A1 - Lepper, Verena A1 - Siopi, Tzulia A1 - Mahnke, Heinz.Eberhard T1 - Virtual Access to Hidden Texts – Study of Ancient Papyri T2 - Eighth Joint BER II and BESSY II User Meeting, Dec 7-9, 2016, Berlin, Germany N2 - When physical unfolding/unrolling of papyri is not possible or too dangerous for preserving the precious object, tomographic approaches may be the ap- propriate alternative. Requirements are the resolution and the contrast to distinguish writing and substrate. The steps to be performed are the following: (1) Select the object of interest (archaeological arguments, cultural back- ground of the object, etc.). (2) Find the proper physical procedure, especially with respect to contrast, take the tomographic data, e.g. by absorption x-ray tomography. (3) Apply mathematical unfolding transformations to the tomographic data, in order to obtain a 2d-planar reconstruction of text. Y1 - 2016 ER - TY - JOUR A1 - Baum, Daniel A1 - Lindow, Norbert A1 - Hege, Hans-Christian A1 - Lepper, Verena A1 - Siopi, Tzulia A1 - Kutz, Frank A1 - Mahlow, Kristin A1 - Mahnke, Heinz-Eberhard T1 - Revealing hidden text in rolled and folded papyri JF - Applied Physics A N2 - 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. Y1 - 2017 U6 - https://doi.org/10.1007/s00339-017-0808-6 VL - 123 IS - 3 SP - 171 ER - TY - GEN A1 - Baum, Daniel A1 - Lindow, Norbert A1 - Hege, Hans-Christian A1 - Lepper, Verena A1 - Siopi, Tzulia A1 - Kutz, Frank A1 - Mahlow, Kristin A1 - Mahnke, Heinz-Eberhard T1 - Revealing hidden text in rolled and folded papyri N2 - 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. T3 - ZIB-Report - 17-02 KW - unfolding, papyri, computed tomography Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-61826 SN - 1438-0064 ER - TY - JOUR A1 - Mahnke, Heinz-Eberhard A1 - Arlt, Tobias A1 - Baum, Daniel A1 - Hege, Hans-Christian A1 - Herter, Felix A1 - Lindow, Norbert A1 - Manke, Ingo A1 - Siopi, Tzulia A1 - Menei, Eve A1 - Etienne, Marc A1 - Lepper, Verena T1 - Virtual unfolding of folded papyri JF - Journal of Cultural Heritage N2 - The historical importance of ancient manuscripts is unique since they provide information about the heritage of ancient cultures. Often texts are hidden in rolled or folded documents. Due to recent impro- vements in sensitivity and resolution, spectacular disclosures of rolled hidden texts were possible by X-ray tomography. However, revealing text on folded manuscripts is even more challenging. Manual unfolding is often too risky in view of the fragile condition of fragments, as it can lead to the total loss of the document. X-ray tomography allows for virtual unfolding and enables non-destructive access to hid- den texts. We have recently demonstrated the procedure and tested unfolding algorithms on a mockup sample. Here, we present results on unfolding ancient papyrus packages from the papyrus collection of the Musée du Louvre, among them objects folded along approximately orthogonal folding lines. In one of the packages, the first identification of a word was achieved, the Coptic word for “Lord”. Y1 - 2020 U6 - https://doi.org/10.1016/j.culher.2019.07.007 VL - 41 SP - 264 EP - 269 PB - Elsevier ER - TY - GEN A1 - Mahnke, Heinz-Eberhard A1 - Arlt, Tobias A1 - Baum, Daniel A1 - Hege, Hans-Christian A1 - Herter, Felix A1 - Lindow, Norbert A1 - Manke, Ingo A1 - Siopi, Tzulia A1 - Menei, Eve A1 - Etienne, Marc A1 - Lepper, Verena T1 - Virtual unfolding of folded papyri N2 - The historical importance of ancient manuscripts is unique since they provide information about the heritage of ancient cultures. Often texts are hidden in rolled or folded documents. Due to recent impro- vements in sensitivity and resolution, spectacular disclosures of rolled hidden texts were possible by X-ray tomography. However, revealing text on folded manuscripts is even more challenging. Manual unfolding is often too risky in view of the fragile condition of fragments, as it can lead to the total loss of the document. X-ray tomography allows for virtual unfolding and enables non-destructive access to hid- den texts. We have recently demonstrated the procedure and tested unfolding algorithms on a mockup sample. Here, we present results on unfolding ancient papyrus packages from the papyrus collection of the Musée du Louvre, among them objects folded along approximately orthogonal folding lines. In one of the packages, the first identification of a word was achieved, the Coptic word for “Lord”. T3 - ZIB-Report - 19-44 Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-74338 SN - 1438-0064 ER - TY - GEN A1 - Baum, Daniel A1 - Herter, Felix A1 - Lepper, Verena T1 - Jerash Silver Scroll: Virtually Unfolded Volume T2 - figshare N2 - A new virtual unfolding technique was applied to a silver scroll excavated in Jerash, Jordan, in 2014. As result of the unfolding, 17 lines of writing are clearly visible in the unfolded volumetric data that is published here. Y1 - 2020 U6 - https://doi.org/10.6084/m9.figshare.12145236 ER - TY - JOUR A1 - Klenert, Nicolas A1 - Lepper, Verena A1 - Baum, Daniel T1 - A Local Iterative Approach for the Extraction of 2D Manifolds from Strongly Curved and Folded Thin-Layer Structures JF - IEEE Transactions on Visualization and Computer Graphics N2 - Ridge surfaces represent important features for the analysis of 3-dimensional (3D) datasets in diverse applications and are often derived from varying underlying data including flow fields, geological fault data, and point data, but they can also be present in the original scalar images acquired using a plethora of imaging techniques. Our work is motivated by the analysis of image data acquired using micro-computed tomography (μCT) of ancient, rolled and folded thin-layer structures such as papyrus, parchment, and paper as well as silver and lead sheets. From these documents we know that they are 2-dimensional (2D) in nature. Hence, we are particularly interested in reconstructing 2D manifolds that approximate the document’s structure. The image data from which we want to reconstruct the 2D manifolds are often very noisy and represent folded, densely-layered structures with many artifacts, such as ruptures or layer splitting and merging. Previous ridge-surface extraction methods fail to extract the desired 2D manifold for such challenging data. We have therefore developed a novel method to extract 2D manifolds. The proposed method uses a local fast marching scheme in combination with a separation of the region covered by fast marching into two sub-regions. The 2D manifold of interest is then extracted as the surface separating the two sub-regions. The local scheme can be applied for both automatic propagation as well as interactive analysis. We demonstrate the applicability and robustness of our method on both artificial data as well as real-world data including folded silver and papyrus sheets. Y1 - 2023 U6 - https://doi.org/10.1109/TVCG.2023.3327403 ER - TY - JOUR A1 - Herter, Felix A1 - Hege, Hans-Christian A1 - Hadwiger, Markus A1 - Lepper, Verena A1 - Baum, Daniel T1 - Thin-Volume Visualization on Curved Domains JF - Computer Graphics Forum N2 - Thin, curved structures occur in many volumetric datasets. Their analysis using classical volume rendering is difficult because parts of such structures can bend away or hide behind occluding elements. This problem cannot be fully compensated by effective navigation alone, because structure-adapted navigation in the volume is cumbersome and only parts of the structure are visible in each view. We solve this problem by rendering a spatially transformed view into the volume so that an unobscured visualization of the entire curved structure is obtained. As a result, simple and intuitive navigation becomes possible. The domain of the spatial transform is defined by a triangle mesh that is topologically equivalent to an open disc and that approximates the structure of interest. The rendering is based on ray-casting in which the rays traverse the original curved sub-volume. In order to carve out volumes of varying thickness, the lengths of the rays as well as the position of the mesh vertices can be easily modified in a view-controlled manner by interactive painting. We describe a prototypical implementation and demonstrate the interactive visual inspection of complex structures from digital humanities, biology, medicine, and materials science. Displaying the structure as a whole enables simple inspection of interesting substructures in their original spatial context. Overall, we show that transformed views utilizing ray-casting-based volume rendering supported by guiding surface meshes and supplemented by local, interactive modifications of ray lengths and vertex positions, represent a simple but versatile approach to effectively visualize thin, curved structures in volumetric data. Y1 - 2021 U6 - https://doi.org/10.1111/cgf.14296 VL - 40 IS - 3 SP - 147 EP - 157 PB - Wiley-Blackwell Publishing Ltd. CY - United Kingdom ER -