Efficient View Synthesis with Neural Radiance Distribution Field

TL;DR

This paper introduces Neural Radiance Distribution Field (NeRDF), a novel representation for view synthesis that achieves real-time rendering speed with high quality by modeling radiance distributions along rays, outperforming existing methods in speed and efficiency.

Contribution

NeRDF is a new representation that enables fast, high-quality view synthesis using a small network and a single network forwarding per pixel, improving efficiency over NeRF and NeLF.

Findings

Achieves ~254x speed-up over NeRF with similar network size.

Maintains high visual quality with a small network.

Offers a better trade-off among speed, quality, and network size.

Abstract

Recent work on Neural Radiance Fields (NeRF) has demonstrated significant advances in high-quality view synthesis. A major limitation of NeRF is its low rendering efficiency due to the need for multiple network forwardings to render a single pixel. Existing methods to improve NeRF either reduce the number of required samples or optimize the implementation to accelerate the network forwarding. Despite these efforts, the problem of multiple sampling persists due to the intrinsic representation of radiance fields. In contrast, Neural Light Fields (NeLF) reduce the computation cost of NeRF by querying only one single network forwarding per pixel. To achieve a close visual quality to NeRF, existing NeLF methods require significantly larger network capacities which limits their rendering efficiency in practice. In this work, we propose a new representation called Neural Radiance Distribution Field (NeRDF) that targets efficient view synthesis in real-time. Specifically, we use a small network similar to NeRF while preserving the rendering speed with a single network forwarding per pixel as in NeLF. The key is to model the radiance distribution along each ray with frequency basis and predict frequency weights using the network. Pixel values are then computed via volume rendering on radiance distributions. Experiments show that our proposed method offers a better trade-off among speed, quality, and network size than existing methods: we achieve a ~254x speed-up over NeRF with similar network size, with only a marginal performance decline. Our project page is at yushuang-wu.github.io/NeRDF.