EGWR: Eurographics Workshop on Rendering

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https://diglib.eg.org/handle/10.2312/378

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Browsing EGWR: Eurographics Workshop on Rendering by Subject "Applications"

Now showing 1 - 5 of 5
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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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    Automatic Cinemagraph Portraits
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Bai, Jiamin; Agarwala, Aseem; Agrawala, Maneesh; Ramamoorthi, Ravi; Nicolas Holzschuch and Szymon Rusinkiewicz
    Cinemagraphs are a popular new type of visual media that lie in-between photos and video; some parts of the frame are animated and loop seamlessly, while other parts of the frame remain completely still. Cinemagraphs are especially effective for portraits because they capture the nuances of our dynamic facial expressions. We present a completely automatic algorithm for generating portrait cinemagraphs from a short video captured with a hand-held camera. Our algorithm uses a combination of face tracking and point tracking to segment face motions into two classes: gross, large-scale motions that should be removed from the video, and dynamic facial expressions that should be preserved. This segmentation informs a spatially-varying warp that removes the large-scale motion, and a graph-cut segmentation of the frame into dynamic and still regions that preserves the finer-scale facial expression motions. We demonstrate the success of our method with a variety of results and a comparison to previous work.
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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.
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    Radiometric Transfer: Example-based Radiometric Linearization of Photographs
    (The Eurographics Association and John Wiley & Sons Ltd., 2015) Li, Han; Peers, Pieter; Jaakko Lehtinen and Derek Nowrouzezahrai
    We present an example-based approach for radiometrically linearizing photographs that takes as input a radiometrically linear exemplar image and a target regular uncalibrated image of the same scene, possibly from a different viewpoint and/or under different lighting. The output of our method is a radiometrically linearized version of the target image. Modeling the change in appearance of a small image patch seen from a different viewpoint and/or under different lighting as a linear 1D subspace, allows us to recast radiometric transfer in a form similar to classic radiometric calibration from exposure stacks. The resulting radiometric transfer method is lightweight and easy to implement. We demonstrate the accuracy and validity of our method on a variety of scenes.