The purpose of video surveillance is not to constantly monitor the image, but the detection and recording of unusual events taking place around the building, in front of the main entrance, in front of the garage, on the terrace. Based on the recorded images, a reconstruction of the events can later be performed. The camera is not used only to record images, but also as a motion detector. Even if nothing is happening, image is being transferred, but it is only recorded upon activation by pre-set events.
For protection of buildings, and especially the areas outside the buildings, surveillance video cameras are highly recommended. Of course it is useful to have a complete system, however even a good camera housing (even though empty) with a red LED which flashes from time to time has a psychological effect. Obvious visible signs of an alarm system presence will avert many attempted burglaries or thefts.
Modern video surveillance systems are computational devices with advanced features and digital data (image) processing that include many possibilities of automation of monitoring and recording of events in supervised areas. All these useful possibilities are achieved by dividing the image into a number of sensor fields, marked out on the image of individual cameras and assigned an operation mode. Depending on the purpose, they may trigger a specific view (zooming on the location of an unusual event), a silent alarm, activation of the alarm monitor, recording of events, communication of an event through various electronic channels, starting or stopping of a certain process etc.