Method of intrusion detection over a wide area

摘要

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 radiation of the beam reflected from the field of view, generating a signal indicative of the distance from the device at which the beam has been reflected for each of a plurality of azimuthal sectors of the field of view, storing a plurality of reference signals which are indicative of the distance of reflection of the beam from each azimuthal sector of the field of view during a reference time period, comparing the signals from a selected time period with the reference signals, and generating an output signal if one of the signals is different from the respective reference signal.