Refractive Radiative Transfer Equation
Refractive Radiative Transfer Equation
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DOI：
10.1145/2557605
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发表时间：
2014-03-01
影响因子：
6.2
通讯作者：
Weiskopf, Daniel
中科院分区：
文献类型：
--
作者：
Ament, Marco;Bergmann, Christoph;Weiskopf, Daniel
我们向图形界引入折射辐射传递方程，用于对具有空间变化折射率的参与介质进行基于物理的渲染。我们回顾了几何非线性光学原理，这对于讨论更通用的光传输方程至关重要。特别是，我们提出了一个具有适合渲染的整体形式的光学模型。我们严格证明光线的连续弯曲会导致辐射亮度的非线性缩放。为了获得物理上正确的结果，我们建立在基本辐射的概念（从不连续折射中得知）的基础上，以在这种复杂的介质中保存能量。此外，通用模型考虑了由于折射率而导致的光速降低，以渲染光回波传播等瞬态效应。我们通过利用折射参与介质中的瞬态光传输扩展光子映射来求解折射体渲染方程。我们展示了我们的方法对以空间连续折射和多重散射为主的媒体渲染图像的正确性的影响。此外，我们的模型使我们能够渲染视觉效果，例如光回声的传播或飞行时间图像，这是以前的方法无法产生的。
We introduce a refractive radiative transfer equation to the graphics community for the physically based rendering of participating media that have a spatially varying index of refraction. We review principles of geometric nonlinear optics that are crucial to discuss a more generic light transport equation. In particular, we present an optical model that has an integral form suitable for rendering. We show rigorously that the continuous bending of light rays leads to a nonlinear scaling of radiance. To obtain physically correct results, we build on the concept of basic radiance-known from discontinuous refraction-to conserve energy in such complex media. Furthermore, the generic model accounts for the reduction in the speed of light due to the index of refraction to render transient effects like the propagation of light echoes. We solve the refractive volume rendering equation by extending photon mapping with transient light transport in a refractive, participating medium. We demonstrate the impact of our approach on the correctness of rendered images of media that are dominated by spatially continuous refraction and multiple scattering. Furthermore, our model enables us to render visual effects like the propagation of light echoes or time-of-flight imagery that cannot be produced with previous approaches.