GAMES Webinar 2022 – 234期(可微渲染与散射理论) |Lifan Wu(NVIDIA)，Yu Guo(Tencent America)
【GAMES Webinar 2022-234期】(渲染专题-可微渲染与散射理论)
报告题目：Differentiable Time-Gated Rendering
The continued advancements of time-of-flight imaging devices have enabled new imaging pipelines with numerous applications. Consequently, several forward rendering techniques capable of accurately and efficiently simulating these devices have been introduced. However, general-purpose differentiable rendering techniques that estimate derivatives of time-of-flight images are still lacking. In this paper, we introduce a new theory of differentiable time-gated rendering that enjoys the generality of differentiating with respect to arbitrary scene parameters. Our theory also allows the design of advanced Monte Carlo estimators capable of handling cameras with near-delta or discontinuous time gates. We validate our theory by comparing derivatives generated with our technique and finite differences. Further, we demonstrate the usefulness of our technique using a few proof-of-concept inverse-rendering examples that simulate several time-of-flight imaging scenarios.
Lifan Wu is a research scientist at NVIDIA. He received his Ph.D. degree from University of California San Diego in 2020, advised by Prof. Ravi Ramamoorthi. He was awarded the 2019 NVIDIA Graduate Fellowship. Before his Ph.D. study, he obtained his bachelor’s degree from Tsinghua University in 2015.
His research focus is on physically based rendering, aiming at efficient modeling and simulation of complex visual appearance. He also works on differentiable light transport and inverse rendering problems.
报告嘉宾：Yu Guo(Tencent America)
报告题目：Beyond Mie Theory: Systematic Computation of Bulk Scattering Parameters based on Microphysical Wave Optics
Light scattering in participating media and translucent materials is typically modeled using the radiative transfer theory. Under the assumption of independent scattering between particles, it utilizes several bulk scattering parameters to statistically characterize light-matter interactions at the macroscale. To calculate these parameters based on microscale material properties, the Lorenz-Mie theory has been considered the gold standard. In this paper, we present a generalized framework capable of systematically and rigorously computing bulk scattering parameters beyond the far-field assumption of Lorenz-Mie theory. Our technique accounts for microscale wave-optics effects such as diffraction and interference as well as interactions between nearby particles. Our framework is general, can be plugged in any renderer supporting Lorenz-Mie scattering, and allows arbitrary packing rates and particles correlation; we demonstrate this generality by computing bulk scattering parameters for a wide range of materials, including anisotropic and correlated media.
Yu Guo is a research scientist at Tencent America. He received his Ph.D. from University of California, Irvine in 2021, advised by Prof. Shuang Zhao. He works mainly in physics-based rendering with a focus on modeling and simulating how light interacts with complex materials and its inverse problem.
徐昆，清华大学计算机系长聘副教授、博导，国家优秀青年基金获得者。研究兴趣包括计算机图形学，真实感绘制和智能媒体计算。在ACM SIGGRAPH, ACM Transactions on Graphics, IEEE Transactions on Visualization and Computer Graphics, IEEE Transactions on Image Processing等重要会议期刊发表论文30余篇。担任国际期刊The Visual Computer编委 (2019年至今)、Computers & Graphics编委（2020年至今），国际会议Pacific Graphics程序委员会共同主席（2015年）。获国家自然科学奖二等奖一项（排名4），国家科技进步奖二等奖一项（排名4）。获中国计算机学会优秀博士学位论文奖，入选中国科协“青年人才托举工程”。
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