Massive web datasets play a key role in the success of large vision-language models like CLIP and Flamingo. However, the raw web data is noisy, and existing filtering methods to reduce noise often come at the expense of data diversity. Our work focuses on caption quality as one major source of noise, and studies how generated captions can increase the utility of web-scraped datapoints with nondescript text. Through exploring different mixing strategies for raw and generated captions, we outperform the best filtering method proposed by the DataComp benchmark by 2% on ImageNet and 4% on average across 38 tasks, given a candidate pool of 128M image-text pairs. Our best approach is also 2x better at Flickr and MS-COCO retrieval. We then analyze what makes synthetic captions an effective source of text supervision. In experimenting with different image captioning models, we also demonstrate that the performance of a model on standard image captioning benchmarks (e.g., NoCaps CIDEr) is not a reliable indicator of the utility of the captions it generates for multimodal training. Finally, our experiments with using generated captions at DataComp's large scale (1.28B image-text pairs) offer insights into the limitations of synthetic text, as well as the importance of image curation with increasing training data quantity.

通过探索不同的混合策略，我们发现合成字幕能够增加网络爬取数据点的效用，并且在38个任务中，对于ImageNet表现比DataComp基准提高2%， 平均值提高4%。此外，我们发现使用合成字幕进行多模态训练时，标准图像字幕基准的性能并不可靠，还对1.28B 图像 - 文本对的大规模分析提供了对合成文本的局限性和随着训练数据数量增加图像筛选的重要性的见解。

通过图像描述的方式改进多模态数据集