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7 results on '"Ngan, Addy"'

4. Analysis of Human Faces using a Measurement-Based Skin Reflectance Model.

Author

Weyrich, Tim, Matusik, Wojciech, Pfister, Hanspeter, Bickel, Bernd, Donner, Craig, Chien Tu, McAndless, Janet, Jinho Lee, Ngan, Addy, Jensen, Henrik Wann, and Gross, Markus

Subjects
FACE, OPTICAL reflection, MODELS & modelmaking, REFLECTANCE, SCATTERING (Physics), MATHEMATICS, GEOMETRY
Abstract

We have measured 3D face geometry, skin reflectance, and subsurface scattering using custom-built devices for 149 subjects of varying age, gender, and race. We developed a novel skin reflectance model whose parameters can be estimated from measurements. The model decomposes the large amount of measured skin data into a spatially-varying analytic BRDF, a diffuse albedo map, and diffuse subsurface scattering. Our model is intuitive, physically plausible, and -- since we do not use the original measured data -- easy to edit as well. High-quality renderings come close to reproducing real photographs. The analysis of the model parameters for our sample population reveals variations according to subject age, gender, skin type, and external factors (e.g., sweat, cold, or makeup). Using our statistics, a user can edit the overall appearance of a face (e.g., changing skin type and age) or change small-scale features using texture synthesis (e.g., adding moles and freckles). We are making the collected statistics publicly available to the research community for applications in face synthesis and analysis. [ABSTRACT FROM AUTHOR]

Published
2006
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5. Acquisition and Rendering of Transparent and Refractive Objects

Author

Matusik, Wojciech, Pfister, Hanspeter, Ziegler, Remo, Ngan, Addy, and McMillan, Leonard

Abstract

This paper introduces a new image-based approach to capturing and modeling highly specular, transparent, or translucent objects. We have built a system for automatically acquiring high quality graphical models of objects that are extremely difficult to scan with traditional 3D scanners. The system consists of turntables, a set of cameras and lights, and monitors to project colored backdrops. We use multi-background matting techniques to acquire alpha and environment mattes of the object from multiple viewpoints. Using the alpha mattes we reconstruct an approximate 3D shape of the object. We use the environment mattes to compute a high-resolution surface reflectance field. We also acquire a low-resolution surface reflectance field using the overhead array of lights. Both surface reflectance fields are used to relight the objects and to place them into arbitrary environments. Our system is the first to acquire and render transparent and translucent 3D objects, such as a glass of beer, from arbitrary viewpoints under novel illumination., Engineering and Applied Sciences

Published
2002

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