Collaborative Learning of Anomalies with Privacy (CLAP): A New Baseline for Unsupervised Video Anomaly Detection

核心概念

CLAP is a new baseline for unsupervised video anomaly detection that enables collaborative training of anomaly detection models across multiple participants without compromising data privacy.

摘要

The paper proposes CLAP, a new baseline for unsupervised video anomaly detection that enables collaborative training of anomaly detection models across multiple participants without compromising data privacy.
The key highlights are:

CLAP is designed to train an anomaly detector in a fully unsupervised fashion without any labels, leveraging collaborative learning between multiple participants.
It introduces a common knowledge-based data segregation (CKDS) stage to generate pseudo-labels for normal and anomalous videos, followed by a server knowledge accumulation (SKA) stage and a local feedback or pseudo-label refinement (PLR) stage.
The paper also proposes three new evaluation protocols to benchmark anomaly detection approaches on various scenarios of collaborations and data availability, and modifies existing VAD datasets accordingly.
Experiments on the UCF-Crime and XD-Violence datasets show that CLAP outperforms existing unsupervised and weakly-supervised SOTA methods, while maintaining performance comparable to centralized training even in challenging collaborative settings.
The paper discusses the impact of the number of participants and the availability of partial weak supervision on the performance of CLAP.

統計資料

The variance of the difference in the feature magnitude between consecutive segments in a given anomalous video is higher than in a normal video.
The entropy of the covariance matrix computed based on the features is generally expected to be lower for normal videos compared to anomalous videos.
The number of participants has an impact on the performance of CLAP, with a drop in performance when the number of participants is increased to 50.

引述

"Unsupervised (US) video anomaly detection (VAD) in surveillance applications is gaining more popularity recently due to its practical real-world applications."
"Anomalies are often unknown and it is not feasible to collect all possible anomaly examples for a model to learn from. Furthermore, anomalies are rare in nature, and annotating large amounts of data is laborious."

從以下內容提煉的關鍵洞見

Collaborative Learning of Anomalies with Privacy (CLAP) for Unsupervised Video Anomaly Detection

by Anas Al-lahh... 於 arxiv.org 04-02-2024

https://arxiv.org/pdf/2404.00847.pdf

深入探究

How can CLAP be extended to handle dynamic changes in the participant pool, such as new participants joining or existing participants leaving the collaborative training

To handle dynamic changes in the participant pool, CLAP can be extended by implementing a mechanism for onboarding new participants and offboarding existing participants seamlessly. When a new participant joins, they can go through a registration process where they share their data distribution and model parameters with the server. The server can then incorporate this new participant into the collaborative training by adjusting the aggregation process to include the new participant's contributions. Existing participants can be removed by updating the aggregation process to exclude their contributions. This way, CLAP can adapt to changes in the participant pool without disrupting the training process.

What are the potential challenges and limitations of applying CLAP to real-world video surveillance systems with diverse data sources and varying degrees of data quality

Applying CLAP to real-world video surveillance systems with diverse data sources and varying data quality can present several challenges and limitations. One challenge is the heterogeneity of data sources, which may have different formats, resolutions, and levels of noise. CLAP may struggle to effectively learn from such diverse data sources and may require additional preprocessing steps to standardize the data. Another challenge is the varying degrees of data quality, which can impact the performance of the anomaly detection model. Low-quality data may introduce noise and inconsistencies that could affect the model's ability to generalize.
Furthermore, the privacy concerns associated with sharing surveillance data among different entities can be a significant limitation. Ensuring data privacy and security while enabling collaborative training is crucial but challenging. Data governance, encryption techniques, and secure communication protocols must be implemented to address these concerns. Additionally, the scalability of CLAP to handle large volumes of data from multiple sources efficiently is another limitation that needs to be considered.

How can the performance of CLAP be further improved by incorporating additional cues or domain-specific knowledge about anomalies in surveillance videos

To improve the performance of CLAP in video surveillance systems, incorporating additional cues or domain-specific knowledge about anomalies can be beneficial. One approach is to integrate contextual information such as time of day, weather conditions, or location into the anomaly detection process. By considering these factors, the model can better differentiate between normal and anomalous events.
Furthermore, leveraging domain-specific knowledge about common types of anomalies in surveillance videos can enhance the model's ability to detect unusual events. For example, if certain types of anomalies are more prevalent in a specific environment (e.g., theft in retail stores), the model can be trained to recognize patterns associated with these anomalies. This domain expertise can guide the feature engineering process and help the model focus on relevant aspects of the data for improved anomaly detection.