  Current Vision-and-Language Navigation (VLN) tasks mainly employ textual
instructions to guide agents. However, being inherently abstract, the same
textual instruction can be associated with different visual signals, causing
severe ambiguity and limiting the transfer of prior knowledge in the vision
domain from the user to the agent. To fill this gap, we propose
Vision-and-Language Navigation with Multi-modal Prompts (VLN-MP), a novel task
augmenting traditional VLN by integrating both natural language and images in
instructions. VLN-MP not only maintains backward compatibility by effectively
handling text-only prompts but also consistently shows advantages with
different quantities and relevance of visual prompts. Possible forms of visual
prompts include both exact and similar object images, providing adaptability
and versatility in diverse navigation scenarios. To evaluate VLN-MP under a
unified framework, we implement a new benchmark that offers: (1) a
training-free pipeline to transform textual instructions into multi-modal forms
with landmark images; (2) diverse datasets with multi-modal instructions for
different downstream tasks; (3) a novel module designed to process various
image prompts for seamless integration with state-of-the-art VLN models.
Extensive experiments on four VLN benchmarks (R2R, RxR, REVERIE, CVDN) show
that incorporating visual prompts significantly boosts navigation performance.
While maintaining efficiency with text-only prompts, VLN-MP enables agents to
navigate in the pre-explore setting and outperform text-based models, showing
its broader applicability.
