Indoor scene reconstruction from monocular images has long been sought after
by augmented reality and robotics developers. Recent advances in neural field
representations and monocular priors have led to remarkable results in
scene-level surface reconstructions. The reliance on Multilayer Perceptrons
(MLP), however, significantly limits speed in training and rendering. In this
work, we propose to directly use signed distance function (SDF) in sparse voxel
block grids for fast and accurate scene reconstruction without MLPs. Our
globally sparse and locally dense data structure exploits surfaces' spatial
sparsity, enables cache-friendly queries, and allows direct extensions to
multi-modal data such as color and semantic labels. To apply this
representation to monocular scene reconstruction, we develop a scale
calibration algorithm for fast geometric initialization from monocular depth
priors. We apply differentiable volume rendering from this initialization to
refine details with fast convergence. We also introduce efficient
high-dimensional Continuous Random Fields (CRFs) to further exploit the
semantic-geometry consistency between scene objects. Experiments show that our
approach is 10x faster in training and 100x faster in rendering while achieving
comparable accuracy to state-of-the-art neural implicit methods.

研究使用 “符号距离函数” 结合 “稀疏体素块网格” 等算法实现室内场景的平面重建，相较于常规算法在训练与渲染速度上有数量级的提升，同时保持与现有方法相当的精度。

基于全局稀疏 - 局部稠密格点的快速单目场景重建

Fast Monocular Scene Reconstruction with Global-Sparse Local-Dense Grids

In this work, we present I$^2$-SDF, a new method for intrinsic indoor scene
reconstruction and editing using differentiable Monte Carlo raytracing on
neural signed distance fields (SDFs). Our holistic neural SDF-based framework
jointly recovers the underlying shapes, incident radiance and materials from
multi-view images. We introduce a novel bubble loss for fine-grained small
objects and error-guided adaptive sampling scheme to largely improve the
reconstruction quality on large-scale indoor scenes. Further, we propose to
decompose the neural radiance field into spatially-varying material of the
scene as a neural field through surface-based, differentiable Monte Carlo
raytracing and emitter semantic segmentations, which enables physically based
and photorealistic scene relighting and editing applications. Through a number
of qualitative and quantitative experiments, we demonstrate the superior
quality of our method on indoor scene reconstruction, novel view synthesis, and
scene editing compared to state-of-the-art baselines.

本研究提出了一种基于神经距离场的方法，利用可微分的蒙特卡罗光线跟踪技术，从多视角图像中恢复室内场景的形状、辐射和材料，并进行物理模拟和逼真的场景编辑。实验结果表明，该方法在室内场景重建、新视角合成和场景编辑方面优于现有的基线方法。