Hierarchical and Modular Surveillance Systems in ITS

Over the last 30 years, video surveillance systems have been a key part of intelligent transportation systems (ITSs), which use various image sensors to capture visual information about vehicles and pedestrians to obtain real-time knowledge of traffic conditions. Specifically, they capture vehicles´ visual appearances and support mining more information about them through ve hicle detection, localization, and classification; license plate recognition; vehicle-behavior analysis; and so forth. They also help generate overall vehicle statistics such as estimations of flow rate, average speed, and density. In addition, video surveillance systems can capture pedestrian visual information to support their detection and behavior analysis, especially their interactions with vehicles, which can help identify impending traffic accidents.