Navigation Instruction Generation with BEV Perception and Large Language Models
Sheng Fan, Rui Liu, Wenguan Wang, Yi Yang
TL;DR
Navigation instruction generation benefits from incorporating 3D scene understanding. BEVInstructor fuses Bird's Eye View representations with perspective cues and tunes Multi-Modal LLMs via parameter-efficient prompts, then progressively refines instructions through instance-guided landmarks. The approach achieves state-of-the-art results across indoor and outdoor VLN benchmarks (R2R, REVERIE, UrbanWalk) with notable gains in SPICE and CIDEr and demonstrates strong qualitative grounding of landmarks. These results highlight the importance of 3D geometry and object semantics in language-grounded navigation and point to future directions in multi-sensor fusion and safety-aware instruction generation.
Abstract
Navigation instruction generation, which requires embodied agents to describe the navigation routes, has been of great interest in robotics and human-computer interaction. Existing studies directly map the sequence of 2D perspective observations to route descriptions. Though straightforward, they overlook the geometric information and object semantics of the 3D environment. To address these challenges, we propose BEVInstructor, which incorporates Bird's Eye View (BEV) features into Multi-Modal Large Language Models (MLLMs) for instruction generation. Specifically, BEVInstructor constructs a PerspectiveBEVVisual Encoder for the comprehension of 3D environments through fusing BEV and perspective features. To leverage the powerful language capabilities of MLLMs, the fused representations are used as visual prompts for MLLMs, and perspective-BEV prompt tuning is proposed for parameter-efficient updating. Based on the perspective-BEV prompts, BEVInstructor further adopts an instance-guided iterative refinement pipeline, which improves the instructions in a progressive manner. BEVInstructor achieves impressive performance across diverse datasets (i.e., R2R, REVERIE, and UrbanWalk).
