Explaining and Mitigating the Modality Gap in Contrastive Multimodal Learning

Fuente: arXiv
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Main Authors: Yaras, Can, Chen, Siyi, Wang, Peng, Qu, Qing
Format: Preprint
Published: 2024
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author Yaras, Can
Chen, Siyi
Wang, Peng
Qu, Qing
author_facet Yaras, Can
Chen, Siyi
Wang, Peng
Qu, Qing
contents Multimodal learning has recently gained significant popularity, demonstrating impressive performance across various zero-shot classification tasks and a range of perceptive and generative applications. Models such as Contrastive Language-Image Pretraining (CLIP) are designed to bridge different modalities, such as images and text, by learning a shared representation space through contrastive learning. Despite their success, the working mechanisms underlying multimodal learning are not yet well understood. Notably, these models often exhibit a modality gap, where different modalities occupy distinct regions within the shared representation space. In this work, we conduct an in-depth analysis of the emergence of modality gap by characterizing the gradient flow learning dynamics. Specifically, we identify the critical roles of mismatched data pairs and a learnable temperature parameter in causing and perpetuating the modality gap during training. Furthermore, our theoretical insights are validated through experiments on practical CLIP models. These findings provide principled guidance for mitigating the modality gap, including strategies such as appropriate temperature scheduling and modality swapping. Additionally, we demonstrate that closing the modality gap leads to improved performance on tasks such as image-text retrieval.
format Preprint
id arxiv_https___arxiv_org_abs_2412_07909
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Explaining and Mitigating the Modality Gap in Contrastive Multimodal Learning
Yaras, Can
Chen, Siyi
Wang, Peng
Qu, Qing
Machine Learning
Artificial Intelligence
Computer Vision and Pattern Recognition
Multimodal learning has recently gained significant popularity, demonstrating impressive performance across various zero-shot classification tasks and a range of perceptive and generative applications. Models such as Contrastive Language-Image Pretraining (CLIP) are designed to bridge different modalities, such as images and text, by learning a shared representation space through contrastive learning. Despite their success, the working mechanisms underlying multimodal learning are not yet well understood. Notably, these models often exhibit a modality gap, where different modalities occupy distinct regions within the shared representation space. In this work, we conduct an in-depth analysis of the emergence of modality gap by characterizing the gradient flow learning dynamics. Specifically, we identify the critical roles of mismatched data pairs and a learnable temperature parameter in causing and perpetuating the modality gap during training. Furthermore, our theoretical insights are validated through experiments on practical CLIP models. These findings provide principled guidance for mitigating the modality gap, including strategies such as appropriate temperature scheduling and modality swapping. Additionally, we demonstrate that closing the modality gap leads to improved performance on tasks such as image-text retrieval.
title Explaining and Mitigating the Modality Gap in Contrastive Multimodal Learning
topic Machine Learning
Artificial Intelligence
Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2412.07909