Neural Radiance Fields (NeRF) have emerged as a powerful representation for the task of novel view synthesis due to their simplicity and state-of-the-art performance. Though NeRF can produce photorealistic renderings of unseen viewpoints when many input views are available, its performance drops significantly when this number is reduced. We observe that the majority of artifacts in sparse input scenarios are caused by errors in the estimated scene geometry, and by divergent behavior at the start of training. We address this by regularizing the geometry and appearance of patches rendered from unobserved viewpoints, and annealing the ray sampling space during training. We additionally use a normalizing flow model to regularize the color of unobserved viewpoints. Our model outperforms not only other methods that optimize over a single scene, but in many cases also conditional models that are extensively pre-trained on large multi-view datasets.

我们通过正则化几何和外观来解决NeRF在输入视图位数较少时的性能下降问题，同时在训练期间通过退火光线采样间隔和使用正则化流模型来处理未观察到视点的颜色，从而得到了一种可超过其他方法的模型。

RegNeRF：为稀疏输入提供视角综合的神经光辐射场正则化