Browsing by Author "Jarabo, Adrián"

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    CEIG 2019: Frontmatter
    (Eurographics Association, 2019) Casas, Dan; Jarabo, Adrián; Casas, Dan and Jarabo, Adrián
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    Computing the Bidirectional Scattering of a Microstructure Using Scalar Diffraction Theory and Path Tracing
    (The Eurographics Association and John Wiley & Sons Ltd., 2020) Falster, Viggo; Jarabo, Adrián; Frisvad, Jeppe Revall; Eisemann, Elmar and Jacobson, Alec and Zhang, Fang-Lue
    Most models for bidirectional surface scattering by arbitrary explicitly defined microgeometry are either based on geometric optics and include multiple scattering but no diffraction effects or based on wave optics and include diffraction but no multiple scattering effects. The few exceptions to this tendency are based on rigorous solution of Maxwell's equations and are computationally intractable for surface microgeometries that are tens or hundreds of microns wide. We set up a measurement equation for combining results from single scattering scalar diffraction theory with multiple scattering geometric optics using Monte Carlo integration. Since we consider an arbitrary surface microgeometry, our method enables us to compute expected bidirectional scattering of the metasurfaces with increasingly smaller details seen more and more often in production. In addition, we can take a measured microstructure as input and, for example, compute the difference in bidirectional scattering between a desired surface and a produced surface. In effect, our model can account for both diffraction colors due to wavelength-sized features in the microgeometry and brightening due to multiple scattering. We include scalar diffraction for refraction, and we verify that our model is reasonable by comparing with the rigorous solution for a microsurface with half ellipsoids.
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    A Learned Radiance-Field Representation for Complex Luminaires
    (The Eurographics Association, 2022) Condor, Jorge; Jarabo, Adrián; Ghosh, Abhijeet; Wei, Li-Yi
    We propose an efficient method for rendering complex luminaires using a high quality octree-based representation of the luminaire emission. Complex luminaires are a particularly challenging problem in rendering, due to their caustic light paths inside the luminaire. We reduce the geometric complexity of luminaires by using a simple proxy geometry, and encode the visuallycomplex emitted light field by using a neural radiance field. We tackle the multiple challenges of using NeRFs for representing luminaires, including their high dynamic range, high-frequency content and null-emission areas, by proposing a specialized loss function. For rendering, we distill our luminaires' NeRF into a plenoctree, which we can be easily integrated into traditional rendering systems. Our approach allows for speed-ups of up to 2 orders of magnitude in scenes containing complex luminaires introducing minimal error.
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    Plenoptic Light Transport
    (2015-11-27) Jarabo, Adrián
    In this thesis we focus on the multidimensional nature of light transport as described by the plenoptic function, and in particular in the angular and temporal domains. While traditional imaging has been limited to bidimensional images, the emerging field of Computational Imaging has made increasingly available more complex multidimensional visual data, disambiguating additional domains of the plenoptic function. However, this higher dimensionality requires changing the way that visual information is processed, manipulated, visualized or synthesized. In this thesis we present contributions on these topics, addressing the challenges of adapting and rethinking them to handle higher-dimensional visual information. Specifically, within the angular domain we focus on light field editing, studying interaction paradigms and user workflows when interacting with light fields, and on spatio-angular filtering of complex appearances modeled with BTFs, studying how filtering affects appearance perception. On the other hand, in the temporal domain we focus on transient light transport, where the speed of light cannot longer be considered infinite, including contributions on capture and data processing, light transport simulation and visualization of time-resolved data.