Vision-and-Language Navigation wayfinding agents can be enhanced by exploiting automatically generated navigation instructions. However, existing instruction generators have not been comprehensively evaluated, and the automatic evaluation metrics used to develop them have not been validated. Using human wayfinders, we show that these generators perform on par with or only slightly better than a template-based generator and far worse than human instructors. Furthermore, we discover that BLEU, ROUGE, METEOR and CIDEr are ineffective for evaluating grounded navigation instructions. To improve instruction evaluation, we propose an instruction-trajectory compatibility model that operates without reference instructions. Our model shows the highest correlation with human wayfinding outcomes when scoring individual instructions. For ranking instruction generation systems, if reference instructions are available we recommend using SPICE.

该研究发现BLEU、ROUGE、METEOR和CIDEr指标无法有效评估基于视觉与语言的导航生成器自动生成的导航指令，提出了一种不依赖参考指令的指令-轨迹相容性模型，并建议在有参考指令时使用SPICE进行评估。

关于视觉语言导航指令的评估