Collaborative Research: Fast and Accurate Volumetric Rendering of Scattering Phenomena in Computer Graphics

合作研究：计算机图形学中散射现象的快速精确体绘制由于颗粒介质对光的散射，真实场景常常表现出复杂的体效果。这些效果包括人类已知的一些最壮丽的视觉体验，例如日出和日落的颜色，辉煌的水下焦散，甚至是由于雾，薄雾，阴霾，雨，雪造成的阴沉天气效果，以及由于烟雾和灰尘造成的危险影响。这些效果的逼真视觉再现在各种应用领域具有广泛的影响，包括数字娱乐，科学教育，模拟和培训（飞行，潜水和医疗诊断），以及安全教育（水下探索和搜索工作在烟雾和灰尘的条件）。 虽然在计算机图形学中已经有大量的工作来渲染体积散射的效果，但这些方法通常太慢而无法广泛采用，需要几个小时到几天来模拟单个场景。 这使得在视频游戏、交互式重新照明、虚拟环境或科学教育等应用中包含精确的散射效果是不可行的。本研究的关键观点是，虽然散射的显式数值模拟很困难，但其定性性质相当简单，通常只是涉及到光线的模糊或扩散。研究人员首先确定简单的配置（或几何）的媒体和来源，经常出现在场景中。 他们接下来开发了精确的分析和数据驱动模型，该模型基于辐射传输理论描述了这些配置中光的多次散射。然后，这些模型与蒙特卡洛，硬件和预计算方法相结合，以在各种动态场景和媒体中以交互速率渲染体积效果。 由于分析或算法技术只能与散射特性的基本表示一样准确，因此研究的一个关键部分涉及设计新颖的实验装置，以首次测量广泛的散射介质。 最后，这一努力包括一个重要的教育组成部分，并促进合作精神，新的联合课程，交换学生访问，参观讲座，丰富学生和研究人员的经验。

Collaborative Research: Fast and Accurate Volumetric Rendering ofScattering Phenomena in Computer GraphicsReal world scenes often show complex volumetric effects due to scattering of light by particulate media. These effects include some of the most magnificent visual experiences known to man, such as the colors of sunriseand sunset, the brilliant underwater caustics, or even the gloomy weather effects due to fog, mist, haze, rain, snow, and the hazardous effects due to smoke and dust. Realistic visual reproductions of these effects hasbroad impact in various application domains including digital entertainment, scientific education, simulation and training (flying, diving and medical diagnosis), and safety education (underwater explorations and search efforts in smoky and dusty conditions). While there has been a substantial body of work in computer graphics on rendering the effects of volumetric scattering, those methods are usually too slow to enable widespread adoption, taking hours to days to simulate a single scene. This makes it infeasible to include accurate scattering effects in applications like video games, interactive relighting, virtual environments or scientific education.The key insight in this research is that while the explicit numerical simulation of scattering is difficult, its qualitative properties are quite simple, usually just involving a blurring or spreading out of light.The investigators first identify simple configurations (or geometries) of media and sources which frequently occur in scenes. They next develop accurate analytic and data-driven models that describe multiple scattering of light in these configurations based on the theory of radiative transfer. These models are then leveraged in conjunction with Monte Carlo, hardware and precomputation methods, to render volumetric effects at interactive rates in a wide range of dynamic scenes and media. Since analytic or algorithmic techniques can only be as accurate as the underlying representations of scattering properties, a critical part of the research involves designing novel experimental setups to measure a wide array of scattering media for the first time. Finally, this effort includes a significant educational component and promotes collaborativespirit, with new joint courses, exchange student visits, visitinglectures, enriching the experiences of both students and researchers.