During language acquisition, infants have the benefit of visual cues to
ground spoken language. Robots similarly have access to audio and visual
sensors. Recent work has shown that images and spoken captions can be mapped
into a meaningful common space, allowing images to be retrieved using speech
and vice versa. In this setting of images paired with untranscribed spoken
captions, we consider whether computer vision systems can be used to obtain
textual labels for the speech. Concretely, we use an image-to-words multi-label
visual classifier to tag images with soft textual labels, and then train a
neural network to map from the speech to these soft targets. We show that the
resulting speech system is able to predict which words occur in an
utterance---acting as a spoken bag-of-words classifier---without seeing any
parallel speech and text. We find that the model often confuses semantically
related words, e.g. "man" and "person", making it even more effective as a
semantic keyword spotter.

这篇论文中，采用图像与未翻译口头说明的组合，研究计算机视觉系统是否可以用于获取语音的文本标签，并使用图片到词语多标签视觉分类器标记图像的软文本标签。然后，训练神经网络将语音映射到这些软目标。结果表明，语音识别系统能够预测话语中出现的单词，并作为口头词组分类器，同时还经常混淆语义相关的词，例如 “男人” 和 “人” ，使其效果更好作为语义关键词识别器。