Implicit representations like Neural Radiance Fields (NeRF) showed impressive results for photorealistic rendering of complex scenes with fine details. However, ideal or near-perfectly specular reflecting objects such as mirrors, which are often encountered in various indoor scenes, impose ambiguities and inconsistencies in the representation of the reconstructed scene leading to severe artifacts in the synthesized renderings. In this paper, we present a novel reflection tracing method tailored for the involved volume rendering within NeRF that takes these mirror-like objects into account while avoiding the cost of straightforward but expensive extensions through standard path tracing. By explicitly modeling the reflection behavior using physically plausible materials and estimating the reflected radiance with Monte-Carlo methods within the volume rendering formulation, we derive efficient strategies for importance sampling and the transmittance computation along rays from only few samples. We show that our novel method enables the training of consistent representations of such challenging scenes and achieves superior results in comparison to previous state-of-the-art approaches.

我们提出了一种针对NeRF中参与体积渲染的镜像对象的反射追踪方法，通过明确建模反射行为并使用蒙特卡洛方法估计反射辐射度，我们推导出有效的重要性采样和光线透射率计算策略，从而实现了对具有挑战性场景的一致表示的训练，并在与先前最先进方法的比较中取得了优越的结果。

TraM-NeRF: 通过神经辐射场追踪镜面和近乎完美的镜面反射