“…In this work, we focus on a single fixed camera scenario, since it still captures a wide spread of applications. Another relevant distinction is made between systems oriented to monitoring of traffic scenes, where the main targets are vehicles and pedestrians (see for instance [1,5,6,9]), and systems for video surveillance of unattended areas such as metro platforms,parking areas (see [3,4]) and unmanned railways environments [10]. In the two cases, different a-priori knowledge about objects in the scene can be exploited in order to improve detection and/or tracking.…”