31-Issue 4

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https://diglib.eg.org/handle/10.2312/173

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Browsing 31-Issue 4 by Subject "Applications"

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    Artistic Illumination Transfer for Portraits
    (The Eurographics Association and Blackwell Publishing Ltd., 2012) Chen, Xiaowu; Jin, Xin; Zhao, Qinping; Wu, Hongyu; Fredo Durand and Diego Gutierrez
    Relighting a portrait in a single image is still a challenging problem, particularly when only a single artistic reference photograph or painting is provided. In this paper, we propose an artistic illumination transfer system for portraits based on a database of portrait images (photographs and paintings) associated with hand-drawn illumination templates (276) by artists. Users can select a reference portrait image in the database, and the corresponding illumination template is transferred to an input portrait using image warping. Users can also provide reference portrait images those are not in the database. Based on the Face Illumination Descriptor (FID), the system selects from the database the reference image with the closest illumination to that of the user-provided reference image and adjusts the corresponding illumination template to match the contrast of the user-provided reference image. Experiments on not only paintings but also photographs, paper-cuts and sketches demonstrate that convincing illumination transferred results can be rendered by our system.
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    Example-Based Fractured Appearance
    (The Eurographics Association and Blackwell Publishing Ltd., 2012) Glondu, Loeiz; Muguercia, Lien; Marchal, Maud; Bosch, Carles; Rushmeier, Holly; Dumont, Georges; Drettakis, George; Fredo Durand and Diego Gutierrez
    A common weathering effect is the appearance of cracks due to material fractures. Previous exemplar-based aging and weathering methods have either reused images or sought to replicate observed patterns exactly. We introduce a new approach to exemplar-based modeling that creates weathered patterns on synthetic objects by matching the statistics of fracture patterns in a photograph. We present a user study to determine which statistics are correlated to visual similarity and how they are perceived by the user. We then describe a revised physically-based fracture model capable of producing a wide range of crack patterns at interactive rates. We demonstrate how a Bayesian optimization method can determine the parameters of this model so it can produce a pattern with the same key statistics as an exemplar. Finally, we present results using our approach and various exemplars to produce a variety of fracture effects in synthetic renderings of complex environments. The speed of the fracture simulation allows interactive previews of the fractured results and its application on large scale environments.
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    Matting and Compositing for Fresnel Reflection on Wavy Surfaces
    (The Eurographics Association and Blackwell Publishing Ltd., 2012) Endo, Yuki; Kanamori, Yoshihiro; Fukui, Yukio; Mitani, Jun; Fredo Durand and Diego Gutierrez
    This paper introduces a framework that can extract an alpha matte from a single image with Fresnel reflection, and that can composite other objects with the image such that plausible reflections are included. Our method handles reflections in a plane with small undulations, for example, a water surface with waves or a glossy tabletop. During the matting stage, our method first estimates the transmission color, which is assumed to be uniform, and then calculates a reflection image and alpha matte based on user markups. However, accurate extraction of the matte becomes challenging when a plane has small undulations because these create perturbations in the matte. We therefore propose a filter that can refine the matte effectively. In the compositing stage, the reflection of a composited object is synthesized by ray tracing in real time. We demonstrate the effectiveness of our method through comparisons with ground-truth data and results using natural images as inputs.