  Inferring scene geometry from images via Structure from Motion is a
long-standing and fundamental problem in computer vision. While classical
approaches and, more recently, depth map predictions only focus on the visible
parts of a scene, the task of scene completion aims to reason about geometry
even in occluded regions. With the popularity of neural radiance fields
(NeRFs), implicit representations also became popular for scene completion by
predicting so-called density fields. Unlike explicit approaches. e.g.
voxel-based methods, density fields also allow for accurate depth prediction
and novel-view synthesis via image-based rendering. In this work, we propose to
fuse the scene reconstruction from multiple images and distill this knowledge
into a more accurate single-view scene reconstruction. To this end, we propose
Multi-View Behind the Scenes (MVBTS) to fuse density fields from multiple posed
images, trained fully self-supervised only from image data. Using knowledge
distillation, we use MVBTS to train a single-view scene completion network via
direct supervision called KDBTS. It achieves state-of-the-art performance on
occupancy prediction, especially in occluded regions.
