BEACON: Language-Conditioned Navigation Affordance Prediction under Occlusion

TL;DR

BEACON enables robots to predict navigable target locations in occluded areas by using a bird's-eye view heatmap conditioned on language instructions, improving spatial reasoning beyond visible regions.

Contribution

This work introduces a novel BEV affordance prediction method that incorporates spatial cues into vision-language models to handle occlusions in language-conditioned navigation.

Findings

22.74 percentage points improvement over state-of-the-art

Effective BEV formulation for occlusion reasoning

Validated on occlusion-rich dataset in Habitat simulator

Abstract

Language-conditioned local navigation requires a robot to infer a nearby traversable target location from its current observation and an open-vocabulary, relational instruction. Existing vision-language spatial grounding methods usually rely on vision-language models (VLMs) to reason in image space, producing 2D predictions tied to visible pixels. As a result, they struggle to infer target locations in occluded regions, typically caused by furniture or moving humans. To address this issue, we propose BEACON, which predicts an ego-centric Bird's-Eye View (BEV) affordance heatmap over a bounded local region including occluded areas. Given an instruction and surround-view RGB-D observations from four directions around the robot, BEACON predicts the BEV heatmap by injecting spatial cues into a VLM and fusing the VLM's output with depth-derived BEV features. Using an occlusion-aware dataset built in the Habitat simulator, we conduct detailed experimental analysis to validate both our BEV space formulation and the design choices of each module. Our method improves the accuracy averaged across geodesic thresholds by 22.74 percentage points over the state-of-the-art image-space baseline on the validation subset with occluded target locations. Our project page is: https://xin-yu-gao.github.io/beacon.