Projects

We have built a multispectral LED sphere (light stage) consisting of 168 RGB and color temperature controllable white LED lamps, respectively. The LED sphere has a 2.5 meter diameter steel structure, and employs off-the-shelf programmable LED lamps.

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.

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.

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.

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.

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.

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 />

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.

We propose a practical method to measure spectral skin reflectance as well as a spectral BSSRDF model spanning a wide spectral range from 300nm to 1000nm. We employ a practical capture setup consisting of desktop monitors to illuminate human faces in the visible domain to estimate five parameters of spectral chromophore concentrations including melanin, hemoglobin, and β carotene concentration, melanin blend-type fraction, and epidermal hemoglobin fraction.

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.