We propose a very low-cost inverse optimization method that does not rely on data-driven priors, to obtain high-quality diffuse and specular, albedo and normal maps in the setting of multi-view unknown lighting. We introduce compact neural networks that learn the shading of a given scene by efficiently finding correlations in the appearance across the face.
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Projects
On-site Example-based Material Appearance Acquisition
We present a novel example-based material appearance modeling method suitable for rapid digital content creation by digital artists. Instead of conventional appearance capture methods which also require either knowing or acquiring the shape of an exemplar, we propose a method that simply requires a photograph of a homogeneous material exemplar with arbitrary unknown shape under known environmental illumination.
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Polarization imaging reflectometry in the wild
We present a novel approach for on-site acquisition of surface reflectance for planar, spatially-varying samples in uncontrolled outdoor environments. We exploit the naturally occurring linear polarization of incident illumination and employ polarization imaging from two near orthogonal views close to the Brewster angle of incidence for reflectance estimation.
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Polarization-imaging Surface Reflectometry using Near-field Display
We present a practical method for measurement of spatially varying isotropic surface reflectance of planar samples using a combination of single-view polarization imaging and near-field display illumination. Our approach enables high-quality renderings of planar surfaces while reducing measurements to a near-optimal number for the estimated SVBRDF parameters.
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Practical acquisition and rendering of diffraction effects in surface reflectance
We propose two novel contributions for measurement based rendering of diffraction effects in surface reflectance of planar homogeneous diffractive materials. Firstly for commonly manufactured materials, we propose a practical data-driven rendering technique and a measurement approach to efficiently render complex diffraction effects in real-time. Our measurement step simply involves photographing a planar diffractive sample illuminated with an LED flash and a spectral filter. Secondly, for sharp specular samples, we propose a novel method for practical measurement of the underlying diffraction grating using out-of-focus “bokeh” photography of the specular highlight.
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Practical Acquisition of Shape and Plausible Appearance of Reflective and Translucent Objects
We present a practical method for acquisition of shape and plausible appearance of reflective and translucent objects for realistic rendering and relighting applications. Our approach captures high quality photometric normals as well as transmission vectors for plausible rendering, furthermore, we present a neural rendering approach that enables high quality 3D plausible rendering and geometry reconstruction of reflective and translucent objects.<br />
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Practical acquisition of translucent liquids using polarized transmission imaging
We present a practical method to acquire optical properties of translucent liquids for realistic rendering using polarized transmission imaging of light through a liquid volume in a transparent container.
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Practical Measurement and Reconstruction of Spectral Skin Reflectance
We present two practical methods for measurement of spectral skin reflectance suited for live subjects, and drive a spectral BSSRDF model with appropriate complexity to match skin appearance in photographs, including human faces. Our primary measurement method employs illuminating a subject with two complementary uniform spectral illumination conditions using a multispectral LED sphere to estimate spatially varying parameters of chromophore concentrations in skin. We also demonstrate how to adapt practical skin patch measurements using a hand-held dermatological skin measurement device for skin appearance reconstruction and rendering.
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Real-time rendering of realistic surface diffraction with low rank factorisation
We propose a novel approach for real-time rendering of diffraction effects in surface reflectance in arbitrary environments. Such renderings are usually extremely expensive as they require the computation of a convolution at real-time framerates. In the case of diffraction, the diffraction lobes usually have high frequency details that can only be captured with high resolution convolution kernels which make calculations even more expensive. Our method uses a low rank factorisation of the diffraction lookup table to approximate a 2D convolution kernel by two simpler low rank kernels which allow the computation of the convolution at real-time framerates using two rendering passes. We show realistic renderings in arbitrary environments and achieve a performance from 50 to 100 FPS making possible to use such a technique in real-time applications such as video games and VR.
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Rerendering Landscape Photographs
We present a practical approach for realistic rerendering of landscape photographs. We extract a view dependent depth map from single input landscape images by examining global and local pixel color distributions and demonstrate applications of depth dependent rendering such as novel viewpoints, digital refocusing and dehazing. We also present a simple approach to relight the input landscape photograph under novel sky illumination.
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