@Google, Mountain View

Shuang Zhao ()

E-mail :

Short Bio

Shuang took internship in Internet Graphics Group, Microsoft Research Asia from August 2006 to April 2008. He worked with Xin Tong, Jiaping Wang, Stephen Lin and John Snyder in research projects on BRDF and translucent materials. His work focused on appearance modeling, realistic rendering, real-time rendering and global illumination.

Shuang received his B.Eng. degree from Department of Computer Science & Engineering at Shanghai Jiao Tong University (SJTU) in July 2007. In the Bachelor stage, he was a member of the SJTU team competing in the 2005 ACM International Collegiate Programming Contest (ACM-ICPC) World Finals. His team won the World Champions in the contest.

Publications

Modeling Anisotropic Surface Reflectance with Example-Based Microfacet Synthesis

Jiaping Wang, Shuang Zhao, Xin Tong, John Snyder, Baining Guo

      We present a new technique for the visual modeling of spatiallyvarying anisotropic reflectance using data captured from a single view. Reflectance is represented using a microfacet-based BRDF which tabulates the facets' normal distribution (NDF) as a function of surface location. Data from a single view provides a 2D slice of the 4D BRDF at each surface point from which we fit a partial NDF. The fitted NDF is partial because the single view direction coupled with the set of light directions covers only a portion of the "half-angle" hemisphere. We complete the NDF at each point by applying a novel variant of texture synthesis using similar, overlapping partial NDFs from other points. Our similarity measure allows azimuthal rotation of partial NDFs, under the assumption that reflectance is spatially redundant but the local frame may be arbitrarily oriented. Our system includes a simple acquisition device that collects images over a 2D set of light directions by scanning a linear array of LEDs over a flat sample. Results demonstrate that our approach preserves spatial and directional BRDF details and generates a visually compelling match to measured materials.

ACM SIGGRAPH 2008 (to appear)      [ project ] [ paper ]
 


 
Modeling and Rendering Heterogeneous Translucent Materials using Diffusion Equation

Jiaping Wang, Shuang Zhao, Xin Tong, Stephen Lin, Zhouchen Lin, Yue Dong, Baining Guo, Heung-Yeung Shum

      In this paper, we propose techniques for modeling and rendering of heterogeneous translucent materials that enable acquisition from measured samples, interactive editing of material attributes, and real-time rendering. The materials are assumed to be optically dense such that multiple scattering can be approximated by a diffusion process described by the diffusion equation. For modeling heterogeneous materials, we present an algorithm for acquiring material properties from appearance measurements by solving an inverse diffusion problem. Our modeling algorithm incorporates a regularizer to handle the ill-conditioned inverse problem, an adjoint method to dramatically reduce the computational cost, and a hierarchical GPU implementation for further speedup. To display an object with known material properties, we present an algorithm that performs rendering by solving the diffusion equation with the boundary condition defined by the given illumination environment. This algorithm is centered around object representation by a polygrid, a grid with regular connectivity and an irregular shape, which facilitates the solution of the diffusion equation in arbitrary volumes. Because of the regular connectivity, our rendering algorithm can be implemented on the GPU for real-time performance. We demonstrate our techniques by capturing materials from physical samples and performing real-time rendering and editing with these materials.

ACM Transactions on Graphics, Volume 27, Issue 1 (March 2008)      [ project ] [ paper ]

Selected Honors

ACM International Collegiate Programming Contest

The 2006 ACM International Collegiate Programming Contest - World Finals
    5th Place, Silver Medal, Asia Champions (as an assistant coach)

The 2005 ACM International Collegiate Programming Contest - World Finals
    World Champions, Gold Medal, Asia Champions

The 2004 ACM Asia Programming Contest - Ehime
    Champions

The 2004 ACM Asia Programming Contest - Taipei
    Champions

The 2003 ACM Asia Programming Contest - Beijing
    Champions

Miscellaneous

My Bachelor's thesis (in Simplified Chinese)

My talk slides on Dynamic Programming Algorithm (The talk was given at Microsoft Research Asia in 2005)

My photo album (taken with my Canon 400d camera)

My blog (in Simplified Chinese) and facebook