PAGaS: Pixel-Aligned 1DoF Gaussian Splatting for Depth Refinement
For multi-view stereo depth estimation, PAGaS offers a novel representation that improves depth detail and accuracy, though it is an incremental adaptation of existing GS methods.
PAGaS adapts Gaussian Splatting for multi-view stereo depth refinement by constraining Gaussians to one degree of freedom (depth), producing highly detailed depths and improving geometric fidelity over baselines on 3D reconstruction benchmarks.
Gaussian Splatting (GS) has emerged as an efficient approach for high-quality novel view synthesis. While early GS variants struggled to accurately model the scene's geometry, recent advancements constraining the Gaussians' spread and shapes, such as 2D Gaussian Splatting, have significantly improved geometric fidelity. In this paper, we present Pixel-Aligned 1DoF Gaussian Splatting (PAGaS) that adapts the GS representation from novel view synthesis to the multi-view stereo depth task. Our key contribution is modeling a pixel's depth using one-degree-of-freedom (1DoF) Gaussians that remain tightly constrained during optimization. Unlike existing approaches, our Gaussians' positions and sizes are restricted by the back-projected pixel volumes, leaving depth as the sole degree of freedom to optimize. PAGaS produces highly detailed depths, as illustrated in Figure 1. We quantitatively validate these improvements on top of reference geometric and learning-based multi-view stereo baselines on challenging 3D reconstruction benchmarks. Code: davidrecasens.github.io/pagas