Shell-guided Compression of Voxel Radiance Fields

In this paper, we address the challenge of significant memory consumption and redundant components in large-scale voxel-based model, which are commonly encountered in real-world 3D reconstruction scenarios. We propose a novel method called Shell-guided compression of Voxel Radiance Fields (SVRF), aimed at optimizing voxel-based model into a shell-like structure to reduce storage costs while maintaining rendering accuracy. Specifically, we first introduce a Shell-like Constraint, operating in two main aspects: 1) enhancing the influence of voxels neighboring the surface in determining the rendering outcomes, and 2) expediting the elimination of redundant voxels both inside and outside the surface. Additionally, we introduce an Adaptive Thresholds to ensure appropriate pruning criteria for different scenes. To prevent the erroneous removal of essential object parts, we further employ a Dynamic Pruning Strategy to conduct smooth and precise model pruning during training. The compression method we propose does not necessitate the use of additional labels. It merely requires the guidance of self-supervised learning based on predicted depth. Furthermore, it can be seamlessly integrated into any voxel-grid-based method. Extensive experimental results demonstrate that our method achieves comparable rendering quality while compressing the original number of voxel grids by more than 70%. Our code will be available at: https://github.com/eezkni/SVRF.