A Closer Look at the Explainability of Contrastive Language-Image Pre-training

Fuente: arXiv
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Main Authors: Li, Yi, Wang, Hualiang, Duan, Yiqun, Zhang, Jiheng, Li, Xiaomeng
Format: Preprint
Published: 2023
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author Li, Yi
Wang, Hualiang
Duan, Yiqun
Zhang, Jiheng
Li, Xiaomeng
author_facet Li, Yi
Wang, Hualiang
Duan, Yiqun
Zhang, Jiheng
Li, Xiaomeng
contents Contrastive language-image pre-training (CLIP) is a powerful vision-language model that has shown great benefits for various tasks. However, we have identified some issues with its explainability, which undermine its credibility and limit the capacity for related tasks. Specifically, we find that CLIP tends to focus on background regions rather than foregrounds, with noisy activations at irrelevant positions on the visualization results. These phenomena conflict with conventional explainability methods based on the class attention map (CAM), where the raw model can highlight the local foreground regions using global supervision without alignment. To address these problems, we take a closer look at its architecture and features. Based on thorough analyses, we find the raw self-attentions link to inconsistent semantic regions, resulting in the opposite visualization. Besides, the noisy activations are owing to redundant features among categories. Building on these insights, we propose the CLIP Surgery for reliable CAM, a method that allows surgery-like modifications to the inference architecture and features, without further fine-tuning as classical CAM methods. This approach significantly improves the explainability of CLIP, surpassing existing methods by large margins. Besides, it enables multimodal visualization and extends the capacity of raw CLIP on open-vocabulary tasks without extra alignment. The code is available at https://github.com/xmed-lab/CLIP_Surgery.
format Preprint
id arxiv_https___arxiv_org_abs_2304_05653
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle A Closer Look at the Explainability of Contrastive Language-Image Pre-training
Li, Yi
Wang, Hualiang
Duan, Yiqun
Zhang, Jiheng
Li, Xiaomeng
Computer Vision and Pattern Recognition
Contrastive language-image pre-training (CLIP) is a powerful vision-language model that has shown great benefits for various tasks. However, we have identified some issues with its explainability, which undermine its credibility and limit the capacity for related tasks. Specifically, we find that CLIP tends to focus on background regions rather than foregrounds, with noisy activations at irrelevant positions on the visualization results. These phenomena conflict with conventional explainability methods based on the class attention map (CAM), where the raw model can highlight the local foreground regions using global supervision without alignment. To address these problems, we take a closer look at its architecture and features. Based on thorough analyses, we find the raw self-attentions link to inconsistent semantic regions, resulting in the opposite visualization. Besides, the noisy activations are owing to redundant features among categories. Building on these insights, we propose the CLIP Surgery for reliable CAM, a method that allows surgery-like modifications to the inference architecture and features, without further fine-tuning as classical CAM methods. This approach significantly improves the explainability of CLIP, surpassing existing methods by large margins. Besides, it enables multimodal visualization and extends the capacity of raw CLIP on open-vocabulary tasks without extra alignment. The code is available at https://github.com/xmed-lab/CLIP_Surgery.
title A Closer Look at the Explainability of Contrastive Language-Image Pre-training
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2304.05653