Large-Scale Representation Learning from Visually Grounded Untranscribed Speech
Gabriel Ilharco, Yuan Zhang, Jason Baldridge · 2019
Systems that can associate images with their spoken audio captions are an important step towards visually grounded language learning.We describe a scalable method to automatically generate diverse audio for image captioning datasets.This supports pretraining deep networks for encoding both audio and images, which we do via a dual encoder that learns to align latent representations from both modalities.We show that a masked margin softmax loss for such models is superior to the standard triplet loss.We fine-tune these models on the Flickr8k Audio Captions Corpus and obtain state-of-the-art results-improving recall in the top 10 from 29.6% to 49.5%.We also obtain human ratings on retrieval outputs to better assess the impact of incidentally matching image-caption pairs that were not associated in the data, finding that automatic evaluation substantially underestimates the quality of the retrieved results. * Work done as a member of the Google AI Residency Program.We address the problem of relating images to audio captions that describe them (Figure 1), building on previous research into learning from visually grounded, untranscribed speech (Harwath and Glass, 2015;Sun et al., 2016;Harwath et al., 2016;Chrupała et al., 2017; Kamper et al., 2017b;Chrupała, 2019;Harwath and Glass, 2019).Such problem settings provide opportunities both to improve our theoretical understanding of language