Unsupervised Anomaly Detection from Time-of-Flight Depth Images

TL;DR

This paper explores the use of depth video data for unsupervised anomaly detection, leveraging autoencoder methods and novel loss functions to improve detection accuracy without requiring labeled anomalies.

Contribution

It introduces a novel approach integrating depth data into autoencoder-based anomaly detection, demonstrating improved performance on a large public dataset.

Findings

Depth data enhances anomaly detection accuracy.

Auxiliary foreground masks improve scene analysis.

Proposed method outperforms existing approaches.

Abstract

Video anomaly detection (VAD) addresses the problem of automatically finding anomalous events in video data. The primary data modalities on which current VAD systems work on are monochrome or RGB images. Using depth data in this context instead is still hardly explored in spite of depth images being a popular choice in many other computer vision research areas and the increasing availability of inexpensive depth camera hardware. We evaluate the application of existing autoencoder-based methods on depth video and propose how the advantages of using depth data can be leveraged by integration into the loss function. Training is done unsupervised using normal sequences without need for any additional annotations. We show that depth allows easy extraction of auxiliary information for scene analysis in the form of a foreground mask and demonstrate its beneficial effect on the anomaly detection performance through evaluation on a large public dataset, for which we are also the first ones to present results on.