Open-Vocabulary Action Localization with Iterative Visual Prompting

Fuente: arXiv
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Main Authors: Wake, Naoki, Kanehira, Atsushi, Sasabuchi, Kazuhiro, Takamatsu, Jun, Ikeuchi, Katsushi
Format: Preprint
Published: 2024
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author Wake, Naoki
Kanehira, Atsushi
Sasabuchi, Kazuhiro
Takamatsu, Jun
Ikeuchi, Katsushi
author_facet Wake, Naoki
Kanehira, Atsushi
Sasabuchi, Kazuhiro
Takamatsu, Jun
Ikeuchi, Katsushi
contents Video action localization aims to find the timings of specific actions from a long video. Although existing learning-based approaches have been successful, they require annotating videos, which comes with a considerable labor cost. This paper proposes a training-free, open-vocabulary approach based on emerging off-the-shelf vision-language models (VLMs). The challenge stems from the fact that VLMs are neither designed to process long videos nor tailored for finding actions. We overcome these problems by extending an iterative visual prompting technique. Specifically, we sample video frames and create a concatenated image with frame index labels, allowing a VLM to identify the frames that most likely correspond to the start and end of the action. By iteratively narrowing the sampling window around the selected frames, the estimation gradually converges to more precise temporal boundaries. We demonstrate that this technique yields reasonable performance, achieving results comparable to state-of-the-art zero-shot action localization. These results support the use of VLMs as a practical tool for understanding videos. Sample code is available at https://microsoft.github.io/VLM-Video-Action-Localization/
format Preprint
id arxiv_https___arxiv_org_abs_2408_17422
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Open-Vocabulary Action Localization with Iterative Visual Prompting
Wake, Naoki
Kanehira, Atsushi
Sasabuchi, Kazuhiro
Takamatsu, Jun
Ikeuchi, Katsushi
Computer Vision and Pattern Recognition
Artificial Intelligence
Robotics
Video action localization aims to find the timings of specific actions from a long video. Although existing learning-based approaches have been successful, they require annotating videos, which comes with a considerable labor cost. This paper proposes a training-free, open-vocabulary approach based on emerging off-the-shelf vision-language models (VLMs). The challenge stems from the fact that VLMs are neither designed to process long videos nor tailored for finding actions. We overcome these problems by extending an iterative visual prompting technique. Specifically, we sample video frames and create a concatenated image with frame index labels, allowing a VLM to identify the frames that most likely correspond to the start and end of the action. By iteratively narrowing the sampling window around the selected frames, the estimation gradually converges to more precise temporal boundaries. We demonstrate that this technique yields reasonable performance, achieving results comparable to state-of-the-art zero-shot action localization. These results support the use of VLMs as a practical tool for understanding videos. Sample code is available at https://microsoft.github.io/VLM-Video-Action-Localization/
title Open-Vocabulary Action Localization with Iterative Visual Prompting
topic Computer Vision and Pattern Recognition
Artificial Intelligence
Robotics
url https://arxiv.org/abs/2408.17422