Road traffic, for example, can be monitored to detect accidents, congestion or erratic driver behaviour.
Surveillance combined with number plate recognition can ascertain traffic flows over large areas.
The surveillance and tracking of people have great social and economic benefits, for example in crime prevention, in customer behaviour analysis at department stores, and in secure sites' protection. Visual surveillance is also used to monitor the growth and feeding behaviour of farm animals. There are numerous similar applications. The effectiveness of a surveillance system is increased if the user can obtain from it high level information in a familiar verbal form. To obtain such information it is necessary to employ well established methods in computer vision and image processing such as segmentation, object detection and recognition, motion analysis, model fitting and filtering as well as more recent methods such as Bayesian nets, machine learning, hidden Markov models and principal component analysis.