Abstract: 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.

Abstract: A scanning intrusion detection device is capable of monitoring a large volume of either interior or exterior space from a single relatively inexpensive unit. This intrusion detection device comprises a radiation emitter arranged to scan a beam of infrared radiation about a field of view and means for receiving the radiation of the beam reflected from the field of view. The receiver is arranged to generate 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 during a selected time period. A ram is also provided for 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. The signals from a selected time period are compared with the reference signals and an output signal is generated if one of the signals is different from the respective reference signal.

Abstract: A method of intrusion detection which comprises the steps of: projecting a beam of infrared radiation toward a field of view from a detection device and receiving the radiation of the beam reflected from the field of view, determining the distance from the device at which the beam is reflected by the field of view, generating a signal indicative of the distance from the device at which the beam has been reflected by the field of view during a selected time period, storing a reference signal which is indicative of the distance of reflection of the beam from the field of view during a reference time period, comparing a signal from a selected time period with the reference signal, and generating an output signal if the signal differs from the reference signal in a preselected manner.

Abstract: An intrusion detection device which comprises a radiation emitter arranged to project a beam of infrared radiation toward a field of view and means for receiving the radiation of the beam reflected from the field of view. The receiving means is arranged to generated a signal indicative of the distance from the device at which the beam has between reflected by the field of view during a selected time period. Means is also provided for storing a reference signal which is indicative of the distance of reflection of the beam from the field of view during a reference time period. Further means is provided for comparing a signal from a selected time period with the reference signal and for generating an output signal if the signal differs from the reference signal in a preselected manner.