MAM2017: Eurographics Workshop on Material Appearance Modeling

Permanent URI for this collection

https://diglib.eg.org/handle/10.2312/2631738

Browse

Browsing MAM2017: Eurographics Workshop on Material Appearance Modeling by Subject "I.3.3 [Computer Graphics]"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Challenges in Appearance Capture and Predictive Modeling of Textile Materials
    (The Eurographics Association, 2017) Castillo, Carlos; Aliaga, Carlos; López-Moreno, Jorge; Reinhard Klein and Holly Rushmeier
    The appearance of cloth is the result of complex light interactions within the structures present in textile materials, particularly challenging due to their multi-scale nature. In addition to the inherent complexity of cloth rendering, there is a lack of connection between computer graphics techniques and manufacturing processes followed in industry. We discuss existing techniques and pose questions about which are the right paths to follow for a better synergy between CG and textile research, including (but not restricted to): defining a standard set of properties required to predict the appearance of cloth to be manufactured; developing both acquisition techniques reliable and suitable for industrial processes and other frameworks more focused on inexpensive capturing (e.g. based on single pictures, Pantone labels); finding material representations that are robust in absence of several low-level parameters; creating a standard for color depth depending on the dye type and dying technique; developing a standard to account for post-process steps (washing, chemical treatments, etc) on the mechanical and optical properties of the textiles.
  • Thumbnail Image
    Item
    Diffraction Prediction in HDR Measurements
    (The Eurographics Association, 2017) Lucat, Antoine; Hegedus, R.; Pacanowski, Romain; Reinhard Klein and Holly Rushmeier
    Modern imaging techniques have proved to be very efficient to recover a scene with high dynamic range values. However, this high dynamic range can introduce star-burst patterns around highlights arising from the diffraction of the camera aperture. The spatial extent of this effect can be very wide and alters pixels values, which, in a measurement context, are not reliable anymore. To address this problem, we introduce a novel algorithm that predicts, from a closed-form PSF, where the diffraction will affect the pixels of an HDR image, making it possible to discard them from the measurement. Our results gives better results than common deconvolution techniques and the uncertainty values (convolution kernel and noise) of the algorithm output are recovered.
  • Thumbnail Image
    Item
    Image-based Remapping of Material Appearance
    (The Eurographics Association, 2017) Sztrajman, Alejandro; Krivánek, Jaroslav; Wilkie, Alexander; Weyrich, Tim; Reinhard Klein and Holly Rushmeier
    Digital 3D content creation requires the ability to exchange assets across multiple software applications. For many 3D asset types, standard formats and interchange conventions are available. For material definitions, however, inter-application exchange is still hampered by different software packages supporting different BRDF models. To make matters worse, even if nominally identical BRDF models are supported, these often differ in their implementation, due to optimisations and safeguards in individual renderers. To facilitate appearance-preserving translation between different BRDF models whose precise implementation is not known (arguably the standard case with commercial systems), we propose a robust translation scheme which leaves BRDF evaluation to the targeted rendering system, and which expresses BRDF similarity in image space. As we will show, even naïve applications of a nonlinear fit which uses such an image space residual metric work well in some cases; however, it does suffer from instabilities for certain material parameters. We propose strategies to mitigate these instabilities and perform reliable parameter remappings between differing BRDF definitions. We report on experiences with this remapping scheme, both with respect to robustness and visual differences of the fits.