43-Issue 2

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https://diglib.eg.org/handle/10.2312/3606944

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Browsing 43-Issue 2 by Subject "Appearance and texture representations"

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    Navigating the Manifold of Translucent Appearance
    (The Eurographics Association and John Wiley & Sons Ltd., 2024) Lanza, Dario; Masia, Belen; Jarabo, Adrian; Bermano, Amit H.; Kalogerakis, Evangelos
    We present a perceptually-motivated manifold for translucent appearance, designed for intuitive editing of translucent materials by navigating through the manifold. Classic tools for editing translucent appearance, based on the use of sliders to tune a number of parameters, are challenging for non-expert users: These parameters have a highly non-linear effect on appearance, and exhibit complex interplay and similarity relations between them. Instead, we pose editing as a navigation task in a low-dimensional space of appearances, which abstracts the user from the underlying optical parameters. To achieve this, we build a low-dimensional continuous manifold of translucent appearance that correlates with how humans perceive this type of materials. We first analyze the correlation of different distance metrics in image space with human perception. We select the best-performing metric to build a low-dimensional manifold, which can be used to navigate the space of translucent appearance. To evaluate the validity of our proposed manifold within its intended application scenario, we build an editing interface that leverages the manifold, and relies on image navigation plus a fine-tuning step to edit appearance. We compare our intuitive interface to a traditional, slider-based one in a user study, demonstrating its effectiveness and superior performance when editing translucent objects.
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    ShellNeRF: Learning a Controllable High-resolution Model of the Eye and Periocular Region
    (The Eurographics Association and John Wiley & Sons Ltd., 2024) Li, Gengyan; Sarkar, Kripasindhu; Meka, Abhimitra; Buehler, Marcel; Mueller, Franziska; Gotardo, Paulo; Hilliges, Otmar; Beeler, Thabo; Bermano, Amit H.; Kalogerakis, Evangelos
    Eye gaze and expressions are crucial non-verbal signals in face-to-face communication. Visual effects and telepresence demand significant improvements in personalized tracking, animation, and synthesis of the eye region to achieve true immersion. Morphable face models, in combination with coordinate-based neural volumetric representations, show promise in solving the difficult problem of reconstructing intricate geometry (eyelashes) and synthesizing photorealistic appearance variations (wrinkles and specularities) of eye performances. We propose a novel hybrid representation - ShellNeRF - that builds a discretized volume around a 3DMM face mesh using concentric surfaces to model the deformable 'periocular' region. We define a canonical space using the UV layout of the shells that constrains the space of dense correspondence search. Combined with an explicit eyeball mesh for modeling corneal light-transport, our model allows for animatable photorealistic 3D synthesis of the whole eye region. Using multi-view video input, we demonstrate significant improvements over state-of-the-art in expression re-enactment and transfer for high-resolution close-up views of the eye region.