Browsing by Author "Ciortan, Irina"

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    Aging Prediction of Cultural Heritage Samples Based on Surface Microgeometry
    (The Eurographics Association, 2018) Ciortan, Irina Mihaela; Marchioro, Giacomo; Daffara, Claudia; Pintus, Ruggero; Gobbetti, Enrico; Giachetti, Andrea; Sablatnig, Robert and Wimmer, Michael
    A critical and challenging aspect for the study of Cultural Heritage (CH) assets is related to the characterization of the materials that compose them and to the variation of these materials with time. In this paper, we exploit a realistic dataset of artificially aged metallic samples treated with different coatings commonly used for artworks' protection in order to evaluate different approaches to extract material features from high-resolution depth maps. In particular, we estimated, on microprofilometric surface acquisitions of the samples, performed at different aging steps, standard roughness descriptors used in materials science as well as classical and recent image texture descriptors. We analyzed the ability of the features to discriminate different aging steps and performed supervised classification tests showing the feasibility of a texture-based aging analysis and the effectiveness of coatings in reducing the surfaces' change with time.
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    The Scream (ca. 1910) through the Years: from Photographic Documentation to Spatio-Temporal Modelling
    (The Eurographics Association, 2023) Ciortan, Irina; Trumpy, Giorgio; Sandu, Irina; Bjørngård, Halvor; Bucciero, Alberto; Fanini, Bruno; Graf, Holger; Pescarin, Sofia; Rizvic, Selma
    The Scream (ca. 1910) is one of Edvard Munch's representations of the well-known scene of a man awestruck by the beauty and colors of the sunset over the fjord, painted in oil and tempera on cardboard. Given the age of the artwork, it is expected that its appearance has significantly changed since its creation to the current state. Previous studies found that the yellow and dark red hues that depict the sky are especially sensitive to moisture and light exposure, respectively. In addition, several film photographs were taken of the painting between 1970 and 2003. In this work, we aim to use these photographs in an attempt to model the changes that the artwork withstood, and reconstruct its past appearance. We perform color correction of the photographs, by comparing the unfaded values in the films against reference values in the current version of the painting. To define the reference values, we use the existing knowledge on the highly sensitive areas and other damages that occured to the painting. Finally, we obtain a color transformation function that facilitates the digital rejuvenation of the painting appearance.
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    State-of-the-art in Multi-Light Image Collections for Surface Visualization and Analysis
    (The Eurographics Association and John Wiley & Sons Ltd., 2019) Pintus, Ruggero; Dulecha, Tinsae Gebrechristos; Ciortan, Irina Mihaela; Gobbetti, Enrico; Giachetti, Andrea; Laramee, Robert S. and Oeltze, Steffen and Sedlmair, Michael
    Multi-Light Image Collections (MLICs), i.e., stacks of photos of a scene acquired with a fixed viewpoint and a varying surface illumination, provide large amounts of visual and geometric information. In this survey, we provide an up-to-date integrative view of MLICs as a mean to gain insight on objects through the analysis and visualization of the acquired data. After a general overview of MLICs capturing and storage, we focus on the main approaches to produce representations usable for visualization and analysis. In this context, we first discuss methods for direct exploration of the raw data. We then summarize approaches that strive to emphasize shape and material details by fusing all acquisitions in a single enhanced image. Subsequently, we focus on approaches that produce relightable images through intermediate representations. This can be done both by fitting various analytic forms of the light transform function, or by locally estimating the parameters of physically plausible models of shape and reflectance and using them for visualization and analysis. We finally review techniques that improve object understanding by using illustrative approaches to enhance relightable models, or by extracting features and derived maps. We also review how these methods are applied in several, main application domains, and what are the available tools to perform MLIC visualization and analysis. We finally point out relevant research issues, analyze research trends, and offer guidelines for practical applications.