Browsing by Author "Ritz, Martin"

Now showing 1 - 3 of 3
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    Automated Classification of Crests on Pottery Sherds Using Pattern Recognition on 2D Images
    (The Eurographics Association, 2022) Ritz, Martin; Santos, Pedro; Fellner, Dieter W.; Ponchio, Federico; Pintus, Ruggero
    Manual classification of artefacts is a labor intensive process. Based on 2D images and 3D scans of - for example - ceramic shards, we developed a pattern recognition algorithm which automatically extracts relief features for each newly recorded object and tries to automate the classification process. Based on characteristics found, previously unknown objects are automatically corelated to already classified objects of a collection exhibiting the greatest similarity. As a result, classes of artefacts form iteratively, which ultimately also corresponds to the overall goal which is the automated classification of entire collections. The greatest challenge in developing our software approach was the heterogeneity of reliefs, and in particular the fact that current machine learning approaches were out of question due to the very limited number of objects per class. This led to the implementation of an analytical approach that is capable of performing a classification based on very few artefacts.
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    End-to-end Color 3D Reproduction of Cultural Heritage Artifacts: Roseninsel Replicas
    (The Eurographics Association, 2019) Domajnko, Matevz; Tanksale, Tejas; Tausch, Reimar; Ritz, Martin; Knuth, Martin; Santos, Pedro; Fellner, Dieter W.; Rizvic, Selma and Rodriguez Echavarria, Karina
    Planning exhibitions of cultural artifacts is always challenging. Artifacts can be very sensitive to the environment and therefore their display can be risky. One way to circumvent this is to build replicas of these artifacts. Here, 3D digitization and reproduction, either physical via 3D printing or virtual, using computer graphics, can be the method of choice. For this use case we present a workflow, from photogrammetric acquisition in challenging environments to representation of the acquired 3D models in different ways, such as online visualization and color 3D printed replicas. This work can also be seen as a first step towards establishing a workflow for full color end-to-end reproduction of artifacts. Our workflow was applied on cultural artifacts found around the ''Roseninsel'' (Rose Island), an island in Lake Starnberg (Bavaria), in collaboration with the Bavarian State Archaeological Collection in Munich. We demonstrate the results of the end-to-end reproduction workflow leading to virtual replicas (online 3D visualization, virtual and augmented reality) and physical replicas (3D printed objects). In addition, we discuss potential optimizations and briefly present an improved state-of-the-art 3D digitization system for fully autonomous acquisition of geometry and colors of cultural heritage objects.
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    Lossless Compression of Multi-View Cultural Heritage Image Data
    (The Eurographics Association, 2019) von Buelow, Max; Guthe, Stefan; Ritz, Martin; Santos, Pedro; Fellner, Dieter W.; Rizvic, Selma and Rodriguez Echavarria, Karina
    Photometric multi-view 3D geometry reconstruction and material capture are important techniques for cultural heritage digitalization. Capturing images of artifacts with high resolution and high dynamic range and the possibility to store them losslessly enables future proof application of this data. As the images tend to consume immense amounts of storage, compression is essential for long time archiving. In this paper, we present a lossless image compression approach for multi-view and material reconstruction datasets with a strong focus on data created from cultural heritage digitalization. Our approach achieves compression rates of 2:1 compared against an uncompressed representation and 1.24:1 when compared against Gzip.