4K-NeRF: High Fidelity Neural Radiance Fields at Ultra High Resolutions

Alibaba Group

Visual comparison between DVGO and our method on example scenes in 4K-Synthetic-NeRF and 4K-LLFF.

Abstract

In this paper, we present a novel and effective framework, named 4K-NeRF, to pursue high fidelity view synthesis on the challenging scenarios of ultra high resolutions, building on the methodology of neural radiance fields (NeRF).

The rendering procedure of NeRF-based methods typically relies on a pixel-wise manner in which rays (or pixels) are treated independently on both training and inference phases, limiting its representational ability on describing subtle details, especially when lifting to a extremely high resolution. We address the issue by exploring ray correlation to enhance high-frequency details recovery. Particularly, we use the 3D-aware encoder to model geometric information effectively in a lower resolution space and recover fine details through the 3D-aware decoder, conditioned on ray features and depths estimated by the encoder. Joint training with patch-based sampling further facilitates our method incorporating the supervision from perception oriented regularization beyond pixel-wise loss.

Benefiting from the use of geometry-aware local context, our method can significantly boost rendering quality on high-frequency details compared with modern NeRF methods, and achieve the state-of-the-art visual quality on 4K ultra-high-resolution scenarios.

Pipeline


The overall pipeline of 4K-NeRF. Using patch-based ray sampling, we jointly train the 3D-Aware encoder for embedding 3D geometric information in a lower resolution space and the 3D-Aware decoder for realizing rendering enhancement on high-frequency details in the full resolution space.

Video

The following is a demonstration of videos in four representative scenes. We strongly recommend watching each video in full screen mode for the best visual effect.

Comparison Results

The following shows how our method compares in detail to all kinds of comparison methods in representative scenario.


BibTeX

@article{wang20224k,
      title={4K-NeRF: High Fidelity Neural Radiance Fields at Ultra High Resolutions},
      author={Wang, Zhongshu and Li, Lingzhi and Shen, Zhen and Shen, Li and Bo, Liefeng},
      journal={arXiv preprint arXiv:2212.04701},
      year={2022}
    }