Hubert Mara (moved to Researchgate.net)

"Hundreds of thousands of ancient documents with cuneiform script are known to be in museum collections and are found on a daily basis at archaeological excavations. Analyzing these documents is essential to understand the origins of civilization, legislation and religion. This script is a handwriting and was used for several millennia in the ancient Middle East. Its name is derived from the Latin word for wedge, which is the 3D-shape left by an ancient scribe's stylus, when it was pressed into the soft surface of a clay tablet. Manually drawing and transcribing these tablets is a laborious and tedious task and assistance by an automated and computerized system is highly demanded.

The aim of this thesis is extracting these handwritten characters, i.e. 3D-shapes with high variability. The crucial steps for feature extraction from 2D-manifolds in 3D-space are reliable edge detection and segmentation. This can be achieved using integral invariant filtering, a robust technique known from signal processing and shape matching in 2D-space. In 3D-space the state-of-the-art systems roughly estimate integral invariants for determining small numbers of highly distinctive features to solve puzzles of fractured objects.

In order to precisely determine 3D-shapes of characters the pipeline known from image processing and pattern recognition is adapted for 3D-models. These models have millions of vertices, which are acquired by optical 3D-scanners. The vertices approximate manifolds with an irregular triangular mesh. Different types of integral invariant filtering in multiple scales lead to different high-dimensional feature spaces. Convolutions and combined metrics are applied to the feature spaces to determine connected components i.e. characters with sub-triangle accuracy within a manifold. Concurrently with the design of novel algorithms, the properties of the integral invariants are investigated. Understanding these properties is highly relevant for robust curvature measures and segmentation. The extraction of characters is completed with a Voronoi inspired method resulting in a minimal meaningful vector representation. This representation is an important basis for paleography. Further abstraction and normalization lead to character recognition. The embedment of the proposed methods in the novel and layered GigaMesh software framework enables a wide variety of applications. Memory efficiency and parallel processing were taken into account in the design of the configurable mesh processing pipeline. The pipeline has only one relevant parameter, which is the maximum size of the expected features.

The proposed methods were tested on hundreds of cuneiform tablets as well as on other objects including synthetic datasets. Representative results are shown and an evaluation regarding accuracy and performance of the algorithms are given. Finally observations about integral invariants in higher dimensions are shown and an outlook is given."

Due to increasing demand of archaeologists for accurate and fast documentation of ceramics, we provide an automated system for acquisition and documentation of sherds. This is done by 3D-acquistion using structured light and by estimation of the profile line using the axis of rotation. As ceramics manufactured in South America are not supposed to be manufactured on rotational plates, we conducted experiments together with the German Archaeological Institute (DAI) to apply and adapt our system on freehand manufactured Nasca ceramics. The experiments including a comparison between manual and automated drawings of profile lines were done in-situ at the excavations in Palpa, Peru. To gather a ground truth about the vessels the sherds belong to, we acquired 102 complete vessels with well-known archaeological context. The symmetry of these vessels was analyzed and experiments for automated profile estimation were used to cross-validate existing classification rules. We could show how to assist archaeological work by estimation of profile lines and additional quality features based on the symmetry of the acquired vessels. Furthermore we show how the use of 3D-scanners can be used by estimation of unwrapped surfaces and virtual restoration of decorations of the painted Nasca fine-ware (30–40% of the findings). Therefore we can show that the documentation can be done in a fraction of time compared to manual documentation. We also show how the high resolution 3D-acquisiton can be used to answer archaeological questions about ancient manufacturing techniques of ceramics.

IWR and the Heidelberg University in collaboration with the Heidelberg Academy of Sciences and Humanities are organizing the fifth conference on topics of computational and mathematical methods with applications to the humanities.

Traditionally, the conference is scheduled in autumn in 2017. The conference is planned to synch with some local satellite workshops. More details will be published on the web site:

http://scch2015.wordpress.com

The sheer computing power of modern information technology is changing the face of research not just in science, technology and mathematics, but in humanities and cultural studies too. Recent decades have seen a major shift both in attitudes and deployment of computers, which are now vital and highly effective tools in disciplines where they were once viewed as elaborate typewriters. This revealing volume details the vast array of computing applications that researchers in the humanities now have recourse to, including the dissemination of scholarly information through virtual ‘co-laboratories’, data retrieval, and the modeling of complex processes that contribute to our natural and cultural heritage. One key area covered in this book is the versatility of computers in presenting images and graphics, which is transforming the analysis of data sets and archaeological reconstructions alike.

The papers published here are grouped into three broad categories that cover mathematical and computational methods, research developments in information systems, and a detailed portrayal of ongoing work on documenting, restoring and presenting cultural monuments including the temples in Pompeii and the Banteay Chhmar temples of the Angkorian period in present-day Cambodia. Originally presented at a research workshop in Heidelberg, Germany, they reflect the rapidly developing identity of computational humanities as an interdisciplinary field in its own right, as well as demonstrating the breadth of perspectives in this young and vibrant research area.

Tens of thousands of fragments of ceramics (called sherds for short) are found at every archaeological excavation site and have to be documented for further archaeological research. The traditional documentation is based on the profile line, which is the intersection of the sherd along the axis of symmetry in the direction of the rotational axis. Traditionally this is done by experts by manually drawing the profile line, using different tools like a Profilkamm (profile comb), flexible wires, circle-templates, etc. to estimate the axis of rotation and the profile line. The traditional drawing is error prone and time consuming, therefore a semiautomatic method using a Profilograph was introduced to increase accuracy. Since the measurement is still manually, the time for drawing was not decreased. We propose a fully automatic system for the estimation of the rotational axis and the profile line. For data-acquisition we are using acquisition methods based on the principle of structured light, which have also been compared in respect to accuracy and performance to traditional methods of documentation. Based on continuous experiments and comparisons we show a new method for estimation of the rotational axis and the profile line, which is inspired by traditional archaeological methods. The methods shown in this thesis were tested on synthetic and real data. The experiments with real data were done at the archaeological excavation in Tel Dor in Israel. The results for estimation of the profile line and the comparison between the manual drawings, the Profilograph and the 3D-acquisition by structured light are shown in this thesis. Furthermore methodological experiments of geometrical surface analysis are shown, which demonstrate the possibility of estimation of ancient manufacturing techniques of ceramics. Finally an outlook towards detection of lines and analysis of painted ceramics is given.

Motivated by the demand for robust character extraction from ancient documents with Script in 3D like cuneiform tablets, we are developing curvature based filter algorithms using integral invariants. While previous work was focused on analyzing 3D-models i. e. irregular triangular meshs in ℝ³ , we introduce a fast, efficient adaption for edge detection in raster images. It is an alternative to the Canny edge detector algorithm and other complex algorithms using first and second order derivative filters. Our approach consists of two steps using (i) zero-crossings of volume integral invariants and (ii) surface integral invari-ants to discard false positives introduced by noise. The runtime of these Dual Integral Invariants (DII) is comparable with Difference of Gaussian filtering and it is independent of the number and length of edges. An additional benefit is the constant execution time as line tracing is not necessary. As the proposed algorithm has no smoothing included it preserves smaller features than recent variants of the Canny edge detector. We use artificial data sets with and without a known amount of noise to validate the accuracy of our method in comparison with operators supplied by the OpenCV library. The equidistant spacing of raster images allows fast estimation of the integral invari-ants based on filter masks like Roberts, Scharr and Kirsch. We show the results on well-known standard test images and synthetic data.

Motivated by the demand of today's Assyriologists we develop a system for automated detection and extraction of cuneiform script, which is one of the most important sources for ancient history. Traditional means of documentation are (i) photographs and (ii) manual drawings, which are increasingly replaced by shape acquisition using 3D-scanners resulting in (iii) high-resolution 3D-models. To utilize the full potential of the acquired 3D-data, we propose a filtering algorithm on 2D-manifolds using Multi-Scale Integral Invariants (MSII) to detect characters within a high-dimensional feature space. As MSII filtering is a local method it overcomes the drawbacks of global illumination methods using virtual light sources. This filtering technique allows for rendering false-color images of the tablets without shadowing effects making the tablets already easy to read. With an additional step of the processing pipeline of our software framework emph{GigaMesh}, we can extract vector drawings. These are the basis for character recognition as well as for future paleographic analysis. The vectorized characters are stored in the XML-based emph{Scalable Vector Graphics} (SVG) format. This results in a tremendous reduction of the triangular mesh data to a meaningful spline representation of the tablets' contents.

The extraction of significant structures in arbitrary high-dimensional data sets is a challenging task. Moreover, classifying data points as noise in order to reduce a data set bears special relevance for many application domains. Standard methods such as clustering serve to reduce problem complexity by providing the user with classes of similar entities. However, they usually do not highlight relations between different entities and require a stopping criterion, e.g. the number of clusters to be detected. In this paper, we present a visualization pipeline based on recent advancements in algebraic topology. More precisely, we employ methods from persistent homology that enable topological data analysis on high-dimensional data sets. Our pipeline inherently copes with noisy data and data sets of arbitrary dimensions. It extracts central structures of a data set in a hierarchical manner by using a persistence-based filtering algorithm that is theoretically well-founded. We furthermore introduce persistence rings, a novel visualization technique for a class of topological features-the persistence intervals-of large data sets. Persistence rings provide a unique topological signature of a data set, which helps in recognizing similarities. In addition, we provide interactive visualization techniques that assist the user in evaluating the parameter space of our method in order to extract relevant structures. We describe and evaluate our analysis pipeline by means of two very distinct classes of data sets: First, a class of synthetic data sets containing topological objects is employed to highlight the interaction capabilities of our method. Second, in order to affirm the utility of our technique, we analyse a class of high-dimensional real-world data sets arising from current research in cultural heritage.

Motivated by the challenging questions of todayssinologists we are developing an automated system for processingof ancient Chinese inscriptions (sutras). As these inscriptions arenot accessible due to location or damage our input data are noisyimages of paper showing the texture of stones together with theinscriptions transfered by charcoal or pencil. Due to the vastamount and large sizes of the images we adopted highly paral-lelized – and therefore high-performance – anisotropic filteringusing standard computer hardware. Additionally characters arelocalized/segmented for further processing by Optical CharacterRecognition. Real results for ancient Chinese inscriptions, whichare mimicking non-standardized handwritings are shown.

Zu Beginn soll eine kurze Beschreibung und ein his-torischer Überblick über die Ereignisse gegeben wer-den, die zur Sprengung des Krautturmes, heute regel-mäßig als "Gesprengter Turm" des Heidelberger Schlosses bezeichnet, geführt haben (Abb. 1).

Abstract: This paper provides an overview regarding the application of the Semantic Web oriented technologies we have developed as part of the EPOCH and AMA projects for Cultural Heritage Digital Libraries. We wanted to enhance interoperability among diverse archives and to make disperse digital information available through the web in a standard format. Our toolset includes an application for mapping existing archive schemas to ontology schemas (AMA Mapping Tool), a tool to recursively markup unstructured text documents ( ...

Motivated by the requirements of today’s archaeologists we are developing a system for the documentation of daily finds of excavations using 3D acquisition. The most widespread finds are fragments of ceramics called sherds. We have shown in previous work the acquisition and documentation of these sherds using 3D scanners based on the principle of structured light. The traditional documentation of sherds is based on the extraction of the profile line, which is a horizontal intersection through the orientated sherd. Our system automatically estimates the profile line by use of computerized methods inspired by traditional archaeological work. Based on the methods used for estimation of the profile line, we demonstrate a method for determination of ancient manufacturing techniques, which is important to determine the technological advancement of an ancient culture. As ceramics were generally manufactured on rotational plates, the profile line is theoretically identical for a complete (symmetric) vessel. Due to the manufacturing technique the symmetry is broken and therefore we can determine it by estimating the variances of the shape of the profile line. For the proposed method we use complete vessels, because sherds of excavations of living places have been dumped and re-used as filling material for floors and walls. Therefore sherds virtually never reassemble a complete vessel and therefore no real ground truth is known. As archaeologists are also excavating burial places where individual unbroken ceramics or complete sets of sherds are found, our method can be applied on, but is not limited to, individual vessels. Results for traditionally manufactured new vessels and ancient vessels acquired during our field trip to the excavations in the valley of Palpa, Peru are given and the applicability of the method in archaeology is shown.

Der Krautturm des Heidelberger Schlosses, heute als „Gesprengter Turm“ bekannt, wurde 1693 im Zuge des Pfälzer Erbfolgekriegs gesprengt. Der massive Rundturm aus rotem Sandstein, der eine Mauerstärke bis zu 6,50 m besitzt, wurde dabei teilweise zerstört, wobei sich ein riesiges abgesprengtes Mauerstück heute noch eindrucksvoll gegen den Turm legt. Es schien lohnenswert zu sein, mit einem Laserscanner ein maßstabsgetreues Modell des Turms aufzunehmen, um zu testen, inwiefern es möglich ist, diesen Turm virtuell wieder zusammenzusetzen. Zu diesem Zweck wurde der Turm in drei Tagen rundum von verschiedenen Standpunkten aus gescannt. Das Projekt war eine Kooperation von Doktoranden der Fachbereiche Wissenschaftliches Rechnen, Physische Geografie und Europäische Kunstgeschichte der Universität Heidelberg und resultierte aus dem Interesse der Beteiligten, Anwendungen und Möglichkeiten der jeweils anderen Fachbereiche kennenzulernen.

A common part of the documentation of archaeological finds is the drawing of so-called rollouts. Rollouts provide a complete and continuous depiction of graphical elements on the surface of rotation-symmetric objects and are especially useful for the iconographic interpretation of figurative vase painting.

In the past, rollouts were created either by manual drawing or photographically. We propose a new method to generate rollouts in which the tedious process of manual drawing or the disadvantage of having to decide on a specific projection in advance of any photographical process is replaced by the acquisition of a digital coloured surface model using a structured-light 3D scanner. This model is then used to generate high-quality rollouts with arbitrary projection parameters.

To handle curved vessel profiles, we divide the vessel's surface into multiple segments. Each segment is then approximated with a frustum which serves as a developable auxiliary surface. In the rollout generation process, the vessel's surface is projected onto a frustum's mantle, which is then developed into the image plane. The shape of each frustum is selected in such a way that projection distortions are minimized, but interrelated graphical features like figural friezes are still unrolled in one piece. To control distortion effects in rollouts of non-developable surfaces, we investigated the use of cartographic methods.

A first implementation of our method generates true-to-scale rollouts from meshes provided as PLY files and writes them to a raster image file. Our program uses off-screen OpenGL in combination with tiled rendering to generate high-resolution images which are suited for professional printing. Exemplary results from the Austrian Corpus Vasorum Antiquorum (CVA) project of the Kunsthistorisches Museum Wien (KHM - Museum of Art History in Vienna) and the Universalmuseum Joanneum Graz (UMJ) are shown.

Motivated by the requirements of archaeologists we are developing an automated system for acquisition, documentation and management of daily finds of excavations. These daily finds can be separated into large objects like remainders of architecture and small objects of ancient daily life - like ceramics and coins. Ceramics especially are found in numbers of tens of thousands on virtually every excavation, because ceramics have been in use for thousands of years. Until the present day these finds are documented by manual drawings. There is a similar situation in the case of coins, where manual drawings are often used to abstract them from photographs. Therefore we propose an automated acquisition and documentation system based on digital cameras and structured light for small findings. For ceramics we provide further processing to estimate horizontal cross-sections (profile-lines) for printed documentation, as it is done by manual drawing. For this a proper orientation of the acquired 3D-model is required and automatically estimated based on the assumption that ceramics were made on rotational plates (wheels).

We are aware that ceramics might not always have been manufactured on rotational plates, because the wheel was not invented everywhere as for the example in the Americas. Even though ceramics from such areas appear to be rotational symmetric, we developed a method based on shape and symmetry analysis to determine the manufacturing techniques of ceramics. This helps to answer another archaeological question regarding the technological advance of an ancient culture.

Results for accuracy and performance are shown on real data from recent interdisciplinary projects together with archaeologists from Austria, Germany, Israel and Peru. Furthermore we present preliminary results of the integration of coin classification in our documentation system. Additionally we are currently adapting the London Charter to ensure the intellectual integrity, reliability, transparency, documentation, standards, sustainability and accessibility of the information gathered by 3D-acquisition. Finally a summary and an outlook is given.

In the area of archaeology surveying, documentation, classification, archivation and reconstruction of pottery, which is often found as thousands of fragments-so called sherds-at excavations is of major concern since statistics about social, cultural and technological status of a population can be made out of this information. Therefore we are developing an acquisition, classification and reconstruction system that is inspired by the archaeological methods.

Archaeology is at a point where it can benefit greatly from the application of computer vision methods, and in turn provides a large number of new, challenging and interesting conceptual problems and data for computer science. This is true in particular in the study of ceramics - the most abundant and widespread of all archaeological finds. The traditional way of documenting archaeological sherds is to draw the profile line, which is the intersection of a sherd along the axis of symmetry. A profilograph is a mechanical device, which can directly acquire and transfer a profile line by pin-pointing the profile on a sherd to a computer. We developed a fully automated vision system, which is able to compute the profile line out of the acquired 3D model of the fragment. In this paper we want to give a thorough comparison between the traditional manual approach, the profilograph and our system and present an improvement of the robustness of our approach by finding circular rills on the fragments. Practical experiments have been undertaken at the excavation Tel Dor in Israel.

Many artefacts, such as wheel-produced ceramics, are intended to be axially symmetric. Therefore, the boundaries of their intersections by planes that are perpendicular to the axis of rotation should he perfect circles (we shall use the term "horizontal sections" for these sections). However, these ideally symmetric objects may suffer deformations when still on the wheel, or during the diying and firing stages. As a result, the afore-mentioned sections will deviate from perfect circles. In traditional archaeological publications which rely on band drawn single profiles, this information is completely lost - the drawn profile can only represent an average profile. The introduction of accurate mea.iuring devices such as 3D scanning cameras (Leymarie et.al., 2001: Rardan et al. 2001: Sablalnig & Menard 1996) has made 3D representations of pottery available. Using these data, it is nowpossible to deduce the deformations of wheel-produced pottery. A systematic study of these deformations may reveal the technological flaws that induced them, and might possibly be used to characterize workshops methods and production patterns. Our goal here is to provide a simple and convenient method to describe and quantify deformations of ceramics. The combination of an objective and accurate method together with high resolution 3D reconstructions is the key of this research. This enables us to zoom-in into the morphology of the vessels and deduce archaeologically meaningful insights.

The London Charter (www.londoncharter.org) aims to define the basic objectives and principles of the use of 3d visualisation methods in relation to intellectual integrity, reliability, transparency, documentation, standards, sustainability and access. The Charter seeks to enhance the rigour with which 3d visualisation methods and outcomes are used and evaluated in the research and communication of cultural heritage, thereby promoting understanding of such methods and outcomes and enabling them to contribute more fully and authoritatively to this domain. Our paper will discuss two projects having as a main outcome a 3D product (in one case a 3D reconstruction of an architectonic feature and the other one a 3D model of cultural heritage artefacts) and how these are related to the principles of the London Charter. The outcomes of this discussion are exemplary templates to guide future users of the Charter, while future work is aiming towards a codification for the use of the Charter.

Abstract Thousands of fragments of ceramics (called sherds for short) are found at archaeological excavation sites. Till today archaeologists have drawn and classified them manually. This method is very time consuming and classification depends on the experiences of the archaeologists. So we developed a system for classification based on 3D-models of the sherds acquired by a 3D-scanner using structured light. The 3D-model is properly orientated by estimating the rotational axis based on a Hough-inspired method. ...

Abstract. We propose a rotational symmetry evaluation method that is used to determine the manufacturing technique of rotationally symmetric pottery like vessels. With the help of scanned 3D data of the surface of the vessel the symme-try is determined which is used to derive ...

@inproceedings{TUW-140552, author = {Mara, Hubert and Hecht, Niels}, title = {3D-Acquisition and Analysis of freehand manufactured NASCA Ceramics}, booktitle = {Proc. of Computer Applications in Archaeology {\&}{\#}65533; Digital Discovery (CAA'06)}, year = {2006}, note = {zur ...

Abstract Thousands of fragments of ceramics (called sherds for short) are found at archaeological excavation sites. One of these excavations sites is Tel Dor in Israel. The excavators in Dor use hand drawings and a profilograph for documen tation of sherds. Both techniques acquire a cross-section of the sherd, the so called profile line, which is used for classification and statistical analysis about the ancient population of Dor. As proposed in previous work we are developing a fully automated system for documentation of sherds by ...

[Zurück]. @article{TUW-139942, author = {Mara, Hubert and Sablatnig, Robert}, title = {3D-Vision Applied in Archaeology}, journal = {Forum Archaeologiae}, year = {2005}, volume = {http://farch.net}, note = {eingeladen} } Erstellt aus der Publikationsdatenbank der Technischen Universität Wien.

Abstract: Every archaeological excavation is confronted with a vast number of ceramic fragments. The documentation, administration and scientific processing of these fragments presents a temporal, personnel and financial problem. Scientific evaluation in archaeological practice often suffers due to extensive amounts of time required for the documentation and administration of ceramic finds.

Abstract Thousands of fragments of ceramics (called sherds for short) are found at every archaeological excavation site and have to be documented for further archaeological research. The traditional documentation is based on the profile, which is the intersection of the sherd along the axis of symmetry in the direction of the rotational axis. Traditionally this is done by experts using different tools like a profile comb to get this profile.

Cuneiform tablets are one of oldest textual artifacts comparable in extent to texts written in Latin or ancient Greek. Since those tablets were used in all of the ancient Near East for over three thousand years [Sod94], many interesting research questions can be answered regarding the development of religion, politics, science, trade and climate change [Kan13]. These tablets were formed from clay and written on by impressing a rectangular stylus [Bor10], require novel methods different from methods used for flat objects i.e. ink on paper.

The digitization of cuneiform tablets and the development of respective databases, started in the same spirit as the Open Data Initiative, has already been initiated by the Cuneiform Database Library Initiative [GWLU05]. At that point, usually, photos and images taken by flatbed scanners are used which are cheap and fast to create. This technique creates blurred and/or shadowed areas if the tablet is damaged or crooked, which is the case for most tablets. Therefore, modern 3D measuring instruments are employed in Jena, Würzburg [CMFW14] and in Heidelberg, Germany [MKJB10] to create highly exact digital replicas used to create appropriate visualizations.

Since the data basis does not consist of regular grids i.e. two dimensional bitmap images as used in the Digital Humanities, new methods for extraction of characters from the geometry of 3D models are required. For that reason, Integral Invariant Filters are applied using a multi-scale approach to extract distinct elements of a cuneiform character in vector representation [MK13]. The Gigamesh Software Framework exports these to the SVG file format. Software packages able to edit SVG files are employed in assyriology and for documentation of archaeological excavations. Therefore, it is already ensured that drawings computed from 3D models are compatible to drawings created by hand.

The representation as vectors as well as the complex 2D layout of cuneiform characters precludes the usage of common OCR methods that require characters to be represented as bitmaps [AGFV14] and/or to be sequentially ordered [RRF13]. The analysis of cuneiform characters requires the transformation of the SVG data into a simplified but mathematically usable representation as mathematical graphs of edges and vertices. Cuneiform characters are mostly identified by the placement of their wedges, a property exploitable by decomposing a graph into disconnected components corresponding to the wedges of a character. Furthermore the complete graphs are also being used to apply methods from the field of graph similarity, methods like graph kernels and spectral embedding [BR10]. The latter approach is especially advantageous if a complex pictorial character cannot be decomposed into sub-structures of features but still has to be compared to another character.

In summary, this work presents methods in the fields of geometry and pattern recognition free of lexicographic and linguistic assumptions. Hence, new approaches are created in which OCR for handwriting can be integrated, exceeding the sole application of cuneiform characters, which are handwritten in 3D. By steadily increasing our data basis for script in 3D the consequential next step will be the integration of machine learning methods. A direct application on epitpahs of medieval Europe is already part of respective online databases [Krö12]. Future application domains are e.g. Roman and Greek inscriptions or Linear B.

Bibliography

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[Bor10] R. Borger. Mesopotamisches Zeichenlexikon, volume 305 of Alter Orient und Altes Testament – Veröffentlichungen zur Kultur und Geschichte des Alten Orients und des Alten Testaments (AOAT). Ugarit-Verlag, 2. edition, 2010.
[BR10] H. Bunke, K. Riesen, Recent advances in graph-based pattern recognition with applications in document analysis, Journal of Pattern Recognition, pp. 1057-1067, Elsevier, 2010.
[CMFW14] M. Cammarosano, G. G.W. Müller, D. Fisseler and F. Weichert. Schriftmetrologie des Keils: Dreidimensionale Analyse von Keileindrücken und Handschriften, Die Welt des Orients, Ausgabe: 44.1, 2014.
[GWLU05] B. Groneberg, F. Weiershäuser, T. Linnemann, and D. Ullrich. Jahrbuch der Max-Planck-Gesellschaft, chapter Digitale Keilschriftbibliothek Lexikalischer Listen aus Assur. Gesellschaft für wissenschaftliche Datenverarbeitung mbH , Göttingen, Germany, 2005.
[Kan13] D. Kaniewski, E. Van Campo, J. Guiot, S. Le Burel, T. Otto and C. Baeteman. Environmental Roots of the Late Bronze Age Crisis. PLoS ONE 8(8), 2013.
[Krö12] S. Krömker, Kombinierte 3D-Datenaufbereitung von Schriftfeldern und Gelände des mittelalterlichen Jüdischen Friedhofs ‚Heiliger Sand’, in: Die SchUM‐Gemeinden Speyer-Worms-Mainz. Auf dem Weg zum Welterbe. Band zur Internationalen Tagung  der Generaldirektion Kulturelles Erbe Rheinland‐Pfalz , angenommen, Mainz, Deutschland, 2012.
[MK13] H. Mara and S. Krömker. Vectorization of 3D-Characters by Integral Invariant Filtering of High-Resolution Triangular Meshes. Proc. of 12. Int. Conference on Document Analysis and Recognition (ICDAR/IAPR), pp. 62–66, Washington, DC, USA, 2013.
[MKJB10] H. Mara, S. Krömker, S. Jakob and B. Breuckmann. GigaMesh and Gilgamesh - 3D Multiscale Integral Invariant Cuneiform Character Extraction. Proc. VAST Int. Symposium on Virtual Reality, Archaeology and Cultural Heritage, pp. 131-138, Palais du Louvre, Paris, France, 2010.
[RRF13] L. Rothacker, M. Rusinol, G.A. Fink, Bag-of-Features HMMs for segmentation-free word spotting in handwritten documents, Proc. of 12th International Conference on Document Analysis and Recognition, pp. 1305-1309, Washington, DC, USA, 2013.
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Motivated by cultural heritage, industry, medicine we are developing 3D-scanners and post-processing systems for rapid and precise documentation of surfaces with curvature. By constantly increasing resolution and accuracy of our system we can enable the documentation of small deviations of even flat surfaces – like frescos. This enables documentation of important features for restoration like small fractures or topology of paintstrokes for scientific research. The 3D-documentation can be done in-situ, radiation-free and contact-free using a structured (coded) light-source and a digital camera. Using light for documentation of colourful painted surface lead to the integration of colour-filtering techniques to ”see thru” the first layer(s) of paint. This approach, typically known from photography, is used to reveal under- drawings of paintings. While photographs suffer from lens distortion lacking a precise scale, we can provide the height of paint-layers in µm in a properly calibrated scale. This method has already been successful tested on synthetic data and medieval paintings and statues, which cover not all painting techniques known to art historians. Therefore we conducted experiments in Pompei to determine the capabilities of our system for fresco paintings. Results shown in this report cover traditional close-range 3D-acquisition for larger fields of view (m2) and multi-spectral 3D-acquisition for paint layers having a field of view of ~600cm2. Regarding performance – having a tremendous amount of frescos – we could show that 3D-acquisition can be done in ~15 minutes per m2. Multi-spectral 3D-acquisition can be applied in a similar fast manner by using expert-knowledge to narrow down the areas of interest.

Usual reconstructions algorithms for ill-posed problems cannot be used effectively for the inverse medium Scattering Problem. This has several reasons, like the non-linearity structure of the problem or the complex-valued data. in this talk i will discuss the performance of several reconstruction algorithms adapted to the setting at hand.