NAS-NeRF: Generative Neural Architecture Search for Neural Radiance Fields

Neural radiance fields (NeRFs) enable high-quality novel view synthesis, but their prohibitively high computational complexity limits deployability, especially on resource-constrained platforms. To enable practical usage of NeRFs, quality tuning is essential to reduce computational complexity, akin to adjustable graphics settings in video games. However while existing solutions strive for efficiency, they use one-size-fits-all architectures regardless of scene complexity, although the same architecture may be unnecessarily large for simple scenes but insufficient for complex ones. Thus as NeRFs become more widely used for 3D visualization, there is a need to dynamically optimize the neural network component of NeRFs to achieve a balance between computational complexity and specific targets for synthesis quality. Addressing this gap, we introduce NAS-NeRF: a generative neural architecture search strategy uniquely tailored to generate NeRF architectures on a per-scene basis by optimizing the trade-off between complexity and performance, while adhering to constraints on computational budget and minimum synthesis quality. Our experiments on the Blender synthetic dataset show the proposed NAS-NeRF can generate architectures up to 5.74$\times$ smaller, with 4.19$\times$ fewer FLOPs, and 1.93$\times$ faster on a GPU than baseline NeRFs, without suffering a drop in SSIM. Furthermore, we illustrate that NAS-NeRF can also achieve architectures up to 23$\times$ smaller, 22$\times$ fewer FLOPs, and 4.7$\times$ faster than baseline NeRFs with only a 5.3\% average SSIM drop. The source code for our work is also made publicly available at https://saeejithnair.github.io/NAS-NeRF.