Neural volumetric representations such as Neural Radiance Fields (NeRF) have emerged as a compelling technique for learning to represent 3D scenes from images with the goal of rendering photorealistic images of the scene from unobserved viewpoints. However, NeRF's computational requirements are prohibitive for real-time applications: rendering views from a trained NeRF requires querying a multilayer perceptron (MLP) hundreds of times per ray. We present a method to train a NeRF, then precompute and store (i.e. "bake") it as a novel representation called a Sparse Neural Radiance Grid (SNeRG) that enables real-time rendering on commodity hardware. To achieve this, we introduce 1) a reformulation of NeRF's architecture, and 2) a sparse voxel grid representation with learned feature vectors. The resulting scene representation retains NeRF's ability to render fine geometric details and view-dependent appearance, is compact (averaging less than 90 MB per scene), and can be rendered in real-time (higher than 30 frames per second on a laptop GPU). Actual screen captures are shown in our video.

该论文提出了一种名为 Sparse Neural Radiance Grid 的新方法，它使用学习的稀疏体素网格表示，通过对神经辐射场（Neural Radiance Fields）进行预处理和存储（烘焙）来实现实时渲染。通过该方法，可以在以往的基础上保留了NeRF渲染精细几何细节和视图相关外观的能力，实现在普通硬件上进行实时渲染。

利用神经辐射场实现实时视图合成