1. A method for automatic surveillance of a monitored area via an aerial vehicle, the method comprising: receiving region of interest (ROI) data indicative of spatial location of regions of interest in a scene; receiving object of interest (OOI) data indicative of characteristics of one or more objects potentially situated within the scene; calculating a repeated sequence of lines of sight (LOS) of a video imaging device, wherein the calculating of the sequence is carried out by weighting: the OOI data; properties of the video imaging device; and properties of the aerial vehicle, automatically pointing the video imaging device at the scene based on the calculated repeated sequence of LOS; applying automatic feature detection algorithms to the video images of the regions of interest, based on OOI data; issuing an alert upon detection of the one or more objects in the scene that are associated with the OOI data, wherein the characteristics comprise at least one of: visual features, tempo spatial behavior, and location within the scene.