Patent ID: 8026820
Filing Date: 2011-09-27
Classification: G08B

Abstract:
1. A method for guarding one or more persons inside a building, the method comprising directing, by means of at least two motion detectors fastened to the building, into a room being monitored at least two non-superimposed beams, at least one of which extends in a width of at most dozens of centimeters across the room being monitored; detecting the movement of each person at least at two separate locations defined by the beams; observing the movement of each person by means of the detections in a predefined time without raising an alarm, if the detected locations of the person form a line of predefined consecutive locations from a predefined initial location to a predefined destination location; raising an alarm if this is not the case; and raising an alarm if the person being monitored is not detected twice successively at the destination location.