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

尽管在图像的记录、处理和复制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。 对于天然材料（如大理石、木材、珊瑚或皮肤）或人造材料（如变色汽车油漆）的特征外观，几乎没有真实的计算机模型。 数字化和创建这些物质的逼真图像涉及再现它们与光的相互作用：光从表面反射或在材料内散射和吸收的方式。 完全可再现性还包括“打印”一种材料作为一个真实的，物理对象，调制我们周围的光。然而，目前不可能像我们在具有固定光泽的纸张上打印颜色或使用3D打印机创建形状那样输出复杂的外观。该项目包括计算机图形学及相关领域的综合性合作研究议程，旨在开发一个端到端的框架，用于获取、表示和制造复杂外观，并了解人类视觉系统如何感知复杂外观。该项目的技术思想是将材料视为薄的三维体积，并填充一般散射点。这与迄今为止计算机图形学的标准方法完全不同，后者将材料纯粹作为表面进行研究。 体积表示包含并概括了目前存在于图形中的各种传统表示，包括基于表面的概念，如双向反射（BRDF），空间变化的BRDF和次表面散射分布（BSSRDF）。 此外，它能够从根本上改进的方法，以有效而通用的采集，快速和逼真的渲染，并表现出超越简单的表面反射和空间均匀的次表面散射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.