GCH 2019 - Eurographics Workshop on Graphics and Cultural Heritage

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https://diglib.eg.org/handle/10.2312/2632818

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Browsing GCH 2019 - Eurographics Workshop on Graphics and Cultural Heritage by Subject "Hardware"

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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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    Lens Calibration for Focus Shift Correction in Close-Range Multispectral Imaging
    (The Eurographics Association, 2019) Brenner, Simon; Sablatnig, Robert; Rizvic, Selma and Rodriguez Echavarria, Karina
    Multispectral imaging has become a popular tool to reveal properties and structures in cultural heritage objects that are hidden to the human observer. One of the inherent problems of multispectral imaging applications is chromatic aberration. Due to an extended spectral range, the effect appears more pronounced than in conventional photography in the visible spectrum. This paper is concerned with longitudinal chromatic aberrations, i.e. shifts of the focal plane along the principal axis of the camera, as they are hard to correct in post-processing and should be avoided during acquisition. To this end, a calibration scheme to measure the wavelength- and distance-dependent focal shift behavior of a given camera/lens system is proposed, which allows for a mechanical compensation at acquisition time. The approach is demonstrated on a multispectral imaging system for historical manuscript analysis. We show that the application of this compensation approach enables the acquisition of in-focus images in non-visible wavelengths using a lens optimized for the visible spectrum only.