UniSplat: Unified Spatio-Temporal Fusion via 3D Latent Scaffolds for Dynamic Driving Scene Reconstruction

Chen Shi1,2, Shaoshuai Shi2,
Xiaoyang Lyu3, Chunyang Liu2, Kehua Sheng2, Bo Zhang2, Li Jiang1
1The Chinese University of Hong Kong, Shenzhen,
2Voyager Research, Didi Chuxing 3The University of Hong Kong

Abstract

Feed-forward 3D reconstruction for autonomous driving has advanced rapidly, yet existing methods struggle with the joint challenges of sparse, non-overlapping camera views and complex scene dynamics. We present UniSplat, a general feed-forward framework that learns robust dynamic scene reconstruction through unified latent spatio-temporal fusion. UniSplat constructs a 3D latent scaffold, a structured representation that captures geometric and semantic scene context by leveraging pretrained foundation models. To effectively integrate information across spatial views and temporal frames, we introduce an efficient fusion mechanism that operates directly within the 3D scaffold, enabling consistent spatio-temporal alignment. To ensure complete and detailed reconstructions, we design a dual-branch decoder that generates dynamic-aware Gaussians from the fused scaffold by combining point-anchored refinement with voxel-based generation, and maintain a persistent memory of static Gaussians to enable streaming scene completion beyond current camera coverage. Extensive experiments on real-world datasets demonstrate that UniSplat achieves state-of-the-art performance in novel view synthesis, while providing robust and high-quality renderings even for viewpoints outside the original camera coverage.

Overview of UniSplat

framework

Overview of UniSplat: Given multi-camera images from vehicle-mounted cameras, UniSplat leverages foundation models to construct geometry-semantic aware 3D latent scaffolds, where unified spatio-temporal fusion is performed. From this scaffold, a dual-branch decoder generates dynamic-aware Gaussian primitives using both point anchors and voxel centers, with dynamic filtering maintaining a persistent memory of static scene content. The red boxes highlight a dynamic car that is filtered out in our memory module (best viewed when zoomed in).