LEGO-SLAM: Language-Embedded Gaussian Optimization SLAM

TL;DR

LEGO-SLAM introduces a real-time, open-vocabulary SLAM system that integrates language understanding into 3D Gaussian Splatting, enabling semantic mapping, efficient memory use, and loop detection without additional models.

Contribution

This work presents the first real-time SLAM framework combining 3D Gaussian Splatting with adaptive language embeddings for open-vocabulary semantic mapping.

Findings

Reduces Gaussian map size by over 60% with maintained quality

Achieves 15 FPS real-time performance

Provides competitive mapping and tracking accuracy

Abstract

Recent advances in 3D Gaussian Splatting (3DGS) have enabled Simultaneous Localization and Mapping (SLAM) systems to build photorealistic maps. However, these maps lack the open-vocabulary semantic understanding required for advanced robotic interaction. Integrating language features into SLAM remains a significant challenge, as storing high-dimensional features demands excessive memory and rendering overhead, while existing methods with static models lack adaptability for novel environments. To address these limitations, we propose LEGO-SLAM (Language-Embedded Gaussian Optimization SLAM), the first framework to achieve real-time, open-vocabulary mapping within a 3DGS-based SLAM system. At the core of our method is a scene-adaptive encoder-decoder that distills high-dimensional language embeddings into a compact 16-dimensional feature space. This design reduces the memory per Gaussian and accelerates rendering, enabling real-time performance. Unlike static approaches, our encoder adapts online to unseen scenes. These compact features also enable a language-guided pruning strategy that identifies semantic redundancy, reducing the map's Gaussian count by over 60\% while maintaining rendering quality. Furthermore, we introduce a language-based loop detection approach that reuses these mapping features, eliminating the need for a separate detection model. Extensive experiments demonstrate that LEGO-SLAM achieves competitive mapping quality and tracking accuracy, all while providing open-vocabulary capabilities at 15 FPS.