Rendering - Experimental Ideas & Implementations 2018

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https://diglib.eg.org/handle/10.2312/2632569

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Browsing Rendering - Experimental Ideas & Implementations 2018 by Subject "Computational photography"

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    Approximate svBRDF Estimation From Mobile Phone Video
    (The Eurographics Association, 2018) Albert, Rachel A.; Chan, Dorian Yao; Goldman, Dan B.; O'Brien, James F.; Jakob, Wenzel and Hachisuka, Toshiya
    We describe a new technique for obtaining a spatially varying BRDF (svBRDF) of a flat object using printed fiducial markers and a cell phone capable of continuous flash video. Our homography-based video frame alignment method does not require the fiducial markers to be visible in every frame, thereby enabling us to capture larger areas at a closer distance and higher resolution than in previous work. Pixels in the resulting panorama are fit with a BRDF based on a recursive subdivision algorithm, utilizing all the light and view positions obtained from the video. We show the versatility of our method by capturing a variety of materials with both one and two camera input streams and rendering our results on 3D objects under complex illumination.
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    Diffuse-Specular Separation using Binary Spherical Gradient Illumination
    (The Eurographics Association, 2018) Kampouris, Christos; Zafeiriou, Stefanos; Ghosh, Abhijeet; Jakob, Wenzel and Hachisuka, Toshiya
    We introduce a novel method for view-independent diffuse-specular separation of albedo and photometric normals without requiring polarization using binary spherical gradient illumination. The key idea is that with binary gradient illumination, a dielectric surface oriented towards the dark hemisphere exhibits pure diffuse reflectance while a surface oriented towards the bright hemisphere exhibits both diffuse and specular reflectance. We exploit this observation to formulate diffuse-specular separation based on color-space analysis of a surface's response to binary spherical gradients and their complements. The method does not impose restrictions on viewpoints and requires fewer photographs for multiview acquisition than polarized spherical gradient illumination. We further demonstrate an efficient two-shot capture using spectral multiplexing of the illumination that enables diffuse-specular separation of albedo and heuristic separation of photometric normals.