PlenOctrees

We propose a framework that enables real-time rendering of Neural Radiance Fields (NeRFs) using plenoptic octrees, or "PlenOctrees". Our method can render at more than 150 fps at 800x800px resolution, which is over 3000x faster than conventional NeRFs, without sacrificing quality.

Real-time performance is achieved by pre-tabulating the NeRF into an octree-based radiance field that we call PlenOctrees. In order to preserve view-dependent effects such as specularities, we propose to encode appearances via closed-form spherical basis functions. Specifically, we show that it is possible to train NeRFs to predict a spherical harmonic representation of radiance, removing the viewing direction as input to the neural network. Furthermore, we show that our PlenOctrees can be directly optimized to further minimize the reconstruction loss, which leads to equal or better quality than competing methods. We further show that this octree optimization step can be used to accelerate the training time, as we no longer need to wait for the NeRF training to converge fully. Our real-time neural rendering approach may potentially enable new applications such as 6-DOF industrial and product visualizations, as well as next generation AR/VR systems.