Improved Anomaly Detection in Crowded Scenes via Cell-based Analysis of Foreground Speed, Size and Texture

TL;DR

This paper introduces a cell-based anomaly detection method for crowded scenes that analyzes foreground motion, size, and texture features, achieving higher accuracy and efficiency than existing approaches.

Contribution

The paper presents a novel cell-based analysis technique that combines motion, size, and texture features with efficient modeling for improved anomaly detection in crowded scenes.

Findings

Outperforms recent methods like MPPCA, social force, and MDT in accuracy.

Significantly faster than the state-of-the-art MDT approach.

Effective in crowded scenes with complex background dynamics.

Abstract

A robust and efficient anomaly detection technique is proposed, capable of dealing with crowded scenes where traditional tracking based approaches tend to fail. Initial foreground segmentation of the input frames confines the analysis to foreground objects and effectively ignores irrelevant background dynamics. Input frames are split into non-overlapping cells, followed by extracting features based on motion, size and texture from each cell. Each feature type is independently analysed for the presence of an anomaly. Unlike most methods, a refined estimate of object motion is achieved by computing the optical flow of only the foreground pixels. The motion and size features are modelled by an approximated version of kernel density estimation, which is computationally efficient even for large training datasets. Texture features are modelled by an adaptively grown codebook, with the number of entries in the codebook selected in an online fashion. Experiments on the recently published UCSD Anomaly Detection dataset show that the proposed method obtains considerably better results than three recent approaches: MPPCA, social force, and mixture of dynamic textures (MDT). The proposed method is also several orders of magnitude faster than MDT, the next best performing method.