MAM2015: Eurographics Workshop on Material Appearance Modeling: Issues and Acquisition

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https://diglib.eg.org/handle/10.2312/13212

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Browsing MAM2015: Eurographics Workshop on Material Appearance Modeling: Issues and Acquisition by Subject "Reflectance"

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    Geometric Accuracy Analysis of Stationary BTF Gonioreflectometers
    (The Eurographics Association, 2015) Havran, V.; Reinhard Klein and Holly Rushmeier
    The accurate BTF data representation requires specialized measurement gantries, some of them designed as gonireflectometers. These consist of an illumination source and a camera mounted on two robotic arms, one degree of freedom possibly achieved by rotation stage which a measured sample is mounted on. While there are several variations of the gonioreflectometer gantry, the principle of all remains the same, positioning directly the illumination and detector on a hemispherical surface over a sample. We analyze the positioning error of such gonioreflectometers. The input parameters are the required spatial resolution of a BTF sample and the distance between the camera used as a detector and the BTF sample. Our analysis confirms that the requirements for mechatronic actuators for the positioning of the sample and arms are very high and near the limit of state of the art technology.
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    Linear Models for Material BTFs and Possible Applications
    (The Eurographics Association, 2015) Brok, D. den; Weinmann, M.; Klein, R.; Reinhard Klein and Holly Rushmeier
    Due to the richness of real-world materials, arguably one of the biggest challenges in rendering is to come up with models that describe their appearance well. The image-based bidirectional texture function (BTF) is known to be able to model many effects that are hard or impossible to reproduce with analytical reflectance models. This advantage comes at the price of demanding storage and acquisition requirements. In previous work, we have demonstrated that these requirements can be lifted to some extent by means of data-driven linear models. We give a more in-depth overview on our research on such models and summarize the applications we investigated so far, followed by an outlook on what might yet be achievable.
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    Quality Assurance Based on Descriptive and Parsimonious Appearance Models
    (The Eurographics Association, 2015) Nielsen, J. B.; Eiriksson, E. R.; Kristensen, R. L.; Wilm, J.; Frisvad, J. R.; Conradsen, K.; Aanæs, H.; Reinhard Klein and Holly Rushmeier
    In this positional paper, we discuss the potential benefits of using appearance models in additive manufacturing, metal casting, wind turbine blade production, and 3D content acquisition. Current state of the art in acquisition and rendering of appearance cannot easily be used for quality assurance in these areas. The common denominator is the need for descriptive and parsimonious appearance models. By 'parsimonious' we mean with few parameters so that a model is useful both for fast acquisition, robust fitting, and fast rendering of appearance. The word 'descriptive' refers to the fact that a model should represent the main features of the acquired appearance data. The solution we propose is to reduce the degrees of freedom by greater use of multivariate statistics.