MD-NeRF: Enhancing Large-Scale Scene Rendering and Synthesis With Hybrid Point Sampling and Adaptive Scene Decomposition

Neural radiance fields (NeRFs) have gained great success in 3-D representation and novel-view synthesis, which attracted great efforts devoted to this area. However, when rendering large-scale scenes from a drone perspective, existing NeRF methods exhibit pronounced distortions in scene detail including absent textures and blurring of small objects. In this letter, we propose MD-NeRF to mitigate such distortions by integrating a hybrid sampling strategy and an adaptive scene decomposition method. Specifically, an anti-aliasing sampling method combining spiral sampling and sampling along rays is presented to address rendering anomalies. In addition, we decompose a large scene into multiple subscenes using a mixture of expert (MoE) modules. A shared expert is introduced to capture common features and reduce redundancy across the specialized experts. Consequently, the combination of these two methods effectively minimizes distortions when rendering large-scale scenes and enables our model to produce finer textures and more coherent details. We have conducted extensive experiments on several large-scale unbounded scene datasets, and the results demonstrate that our approach has achieved state-of-the-art performance on all datasets, most notably evidenced by a 1-dB enhancement in PSNR metrics on the Mill19 dataset.