Leveraging Large Language Models and Vision-Language Models for Training-free Video Anomaly Detection

핵심 개념

A novel training-free method for video anomaly detection that leverages pre-trained large language models and vision-language models to detect anomalies without any task-specific training or data collection.

초록

The paper introduces LAVAD, a training-free method for video anomaly detection (VAD) that leverages pre-trained large language models (LLMs) and vision-language models (VLMs).

The key highlights are:

1. LAVAD is the first training-free method for VAD, diverging from existing state-of-the-art methods that all require some form of training and data collection.

2. LAVAD consists of three main components:

   • Image-Text Caption Cleaning: Uses cross-modal similarity between image and text embeddings to clean noisy captions generated by a captioning model.
   • LLM-based Anomaly Scoring: Leverages the LLM to generate temporal summaries of the video frames and use them to estimate anomaly scores.
   • Video-Text Score Refinement: Further refines the anomaly scores by aggregating scores from semantically similar video snippets.

3. Experiments on two benchmark datasets, UCF-Crime and XD-Violence, show that LAVAD outperforms both unsupervised and one-class VAD methods without requiring any training or data collection.

4. The authors conduct an extensive ablation study to validate the effectiveness of the proposed components and the impact of different design choices.

Overall, the paper presents a novel training-free approach to VAD that demonstrates the potential of leveraging large-scale foundation models for addressing challenging computer vision tasks without the need for task-specific training.

통계

"We evaluate LAVAD on two large datasets featuring real-world surveillance scenarios (UCF-Crime and XD-Violence)."
"The training set of UCF-Crime consists of 800 normal and 810 anomalous videos, while the test set includes 150 normal and 140 anomalous videos."
"XD-Violence is another large-scale dataset for violence detection, comprising 4754 untrimmed videos with audio signals and weak labels that are collected from both movies and YouTube."

인용구

"Crucially, every existing method necessitates a training procedure to establish an accurate VAD system, and this entails some limitations. One primary concern is generalization: a VAD model trained on a specific dataset tends to underperform in videos recorded in different settings (e.g., daylight versus night scenes). Another aspect, particularly relevant to VAD, is the challenge of data collection, especially in certain application domains (e.g. video surveillance) where privacy issues can hinder data acquisition."
"Developing a training-free VAD model is hard due to the lack of explicit visual priors on the target setting. However, such priors might be drawn using large foundation models, renowned for their generalization capability and wide knowledge encapsulation."

핵심 통찰 요약

Harnessing Large Language Models for Training-free Video Anomaly Detection

by Luca Zanella... 게시일 arxiv.org 04-02-2024

https://arxiv.org/pdf/2404.01014.pdf

더 깊은 질문

How can the proposed training-free approach be extended to other computer vision tasks beyond video anomaly detection

The proposed training-free approach can be extended to other computer vision tasks beyond video anomaly detection by leveraging the capabilities of pre-trained language models and vision-language models in a similar manner. For tasks like image classification, object detection, or semantic segmentation, the models can be used to generate textual descriptions for images or video frames, which can then be used to prompt the language models to provide relevant information or make predictions. By adapting the prompting mechanism and the aggregation techniques used in the proposed method, it is possible to apply this approach to a wide range of computer vision tasks without the need for extensive training or data collection.

What are the potential limitations of relying solely on pre-trained language models and vision-language models for anomaly detection, and how can these be addressed in future research

One potential limitation of relying solely on pre-trained language models and vision-language models for anomaly detection is the generalization to unseen or complex anomalies. These models may not have been trained on a diverse range of anomalies, leading to potential blind spots or inaccuracies in anomaly detection. To address this limitation, future research could focus on fine-tuning the pre-trained models on anomaly-specific datasets to improve their anomaly detection capabilities. Additionally, incorporating domain-specific knowledge or features into the models could enhance their ability to detect anomalies in specific contexts or environments.
Another limitation is the potential noise in the textual descriptions generated by the captioning models, which can impact the accuracy of anomaly detection. Future research could explore advanced techniques for cleaning and refining the textual descriptions to ensure they accurately represent the visual content. This could involve incorporating feedback mechanisms or additional context cues to improve the quality of the descriptions and enhance anomaly detection performance.

Given the importance of temporal information in video analysis, how can the proposed method be further improved to better capture and leverage the dynamic aspects of the video scenes

To better capture and leverage the dynamic aspects of video scenes, the proposed method can be further improved by enhancing the temporal aggregation and anomaly scoring mechanisms. One approach could involve incorporating attention mechanisms or recurrent neural networks to model the temporal dependencies and relationships between frames more effectively. By giving more weight to frames that are semantically similar or contextually relevant, the model can better capture the dynamics of the scene and improve anomaly detection accuracy.
Additionally, exploring multi-modal fusion techniques that combine visual, textual, and temporal information could enhance the model's ability to understand and interpret complex video scenes. By integrating features from different modalities in a cohesive manner, the model can extract more comprehensive representations of the video data and make more informed decisions about anomalies. Experimenting with different fusion strategies and architectures could lead to significant improvements in capturing and leveraging the dynamic aspects of video scenes for anomaly detection.