We present a novel approach for detecting global behaviour
anomalies in multiple disjoint cameras by learning
time delayed dependencies between activities cross camera
views. Specifically, we propose to model multi-camera
activities using a Time Delayed Probabilistic Graphical
Model (TD-PGM) with different nodes representing activities
in different semantically decomposed regions from different
camera views, and the directed links between nodes
encoding causal relationships between the activities. A
novel two-stage structure learning algorithm is formulated
to learn globally optimised time-delayed dependencies. A
new cumulative abnormality score is also introduced to replace
the conventional log-likelihood score for gaining significantly
more robust and reliable real-time anomaly detection.
The effectiveness of the proposed approach is validated
using a camera network installed at a busy underground
station.