1. Method for the monitoring of an environment by use of one or more pairs of imagers, each imager monitoring said environment from a different angle of view, comprising the steps of: a) providing one or more pairs of imagers, wherein at least one of said pairs comprises an optical imager and at least one of said pairs comprises a Forward Looking Infra Red (FLIR) imager; b) positioning both imagers of said one or more pairs of imagers on a common vertically oriented pole such that they are located at a distance of 0.5 to 50 meters from each other and capture a same object at a different angle of view, in order to perform a vertical stereoscopic observation of objects; c) defining and storing in a memory, programs for processing, in real-time, photographic data to be obtained from the stereoscopic observation of objects by use of said one or more pairs of imagers; d) determining and storing parameters according to which the observation of a controlled space or sections thereof is effected; e) carrying out an unmanned, real-time vertical stereoscopic observation of said controlled space or sections thereof, according to the observation parameters; f) determining the distance to said observed objects from said one or more pairs of imagers; g) evaluating the size of each of said observed objects; h) classifying a type and degree of danger of each of said observed objects by jointly processing said real-time data obtained from said stereoscopic observation with respect to the angle of view of each of said imagers, the path and size of, and distance from, said observed objects, and said stored danger parameters; and i) providing an indication when one or more of said observed objects is approaching said controlled space and has been classified as having a sufficiently high degree of danger so as to be liable of damaging an authorized body within said controlled space.