A method of scanning intrusion detection which is capable of monitoring a large volume of either interior or exterior space from a single relatively inexpensive unit. This method of intrusion detection comprises the steps of scanning a beam of infrared radiation about a field of view and receiving the...http://www.google.fr/patents/US4967183?utm_source=gb-gplus-shareBrevet US4967183 - Method of intrusion detection over a wide area
