HCC: Large: Collaborative Research: Beyond Flat Images: Acquiring, Processing, and Fabricating Visually Rich Material Appearance

尽管在如何记录、处理和复制图像方面取得了革命性的进步，但我们重新创造视觉体验的能力仍然非常有限。对于天然材质(如大理石、木材、珊瑚或皮肤)或人造材质(如变色汽车涂料)的特征外观，几乎没有逼真的计算机模型。数字化和创建这些物质的逼真图像涉及复制它们与光的相互作用：光从表面反射的方式，或在材料内散射和吸收的方式。完全的重现性还包括将材料打印成调节我们周围光线的真实的物理对象。然而，目前不可能输出复杂的外观，就像我们在具有固定光泽度的纸张上打印颜色的方式，或者使用3D打印机创建形状。该项目包括计算机图形学及相关领域的全面、协作的研究议程，以开发一个端到端的框架，用于获取、表示和制造复杂的外观，并了解人类视觉系统如何感知它。该项目的使能技术思想是将材料视为填充了一般散布地点的薄三维体积。这从根本上背离了迄今为止计算机图形学中的标准方法，即纯粹将材料作为表面来研究。体积表示包含并概括了图形中当前存在的各种常规表示集，包括基于表面的概念，例如双向反射比(BRDF)、空间变化的BRDF和次表面散射分布(BSSRDF)。此外，它还可以从根本上改进方法，以实现高效而通用的采集、快速和逼真的渲染以及显示出简单表面反射和空间均匀次表面散射之外的现象的对象的制造。

Despite revolutionary advances in how images are recorded, manipulated, and reproduced, our ability to re-create the visual experience remains remarkably limited. Few realistic computer models exist for the characteristic appearance of natural materials such as marble, wood, coral, or skin, or man-made ones such as color-shifting automotive paints. Digitizing and creating realistic images of these substances involves reproducing their interaction with light: the way light is reflected from surfaces, or scattered and absorbed within the materials. Full reproducibility also involves "printing" a material as a real, physical object that modulates the light around us. However, it is currently impossible to output complex appearance the way we print color on a paper with fixed gloss, or create shapes using a 3D printer. This project encompasses a comprehensive, collaborative research agenda in computer graphics and related areas, to develop an end-to-end framework for acquiring, representing, and fabricating complex appearance, as well as to understand how it is perceived by the human visual system.The enabling technical idea of the project is to treat materials as thin three-dimensional volumes populated with general scattering sites. This is a radical departure from the hitherto standard approach in computer graphics, which has studied materials purely as surfaces. The volumetric representation subsumes and generalizes the diverse set of conventional representations that currently exist in graphics, including surface-based notions such as bidirectional reflectance (BRDF), spatially varying BRDF, and subsurface scattering distributions (BSSRDF). Moreover, it enables fundamentally improved approaches to efficient yet general acquisition, fast and realistic rendering, and fabrication of objects exhibiting phenomena beyond simple surface reflectance and spatially homogeneous subsurface scattering.