Method for operating movement alarm system to monitor region of civilian/military systems against ingress of unauthorized people, involves producing alarm signal if size representative value lies above lower threshold level of object size

摘要

The method involves forming quotient of an actual output signal level of passive infrared detectors (D1), and determining removal of an object e.g. animal and human, by comparison of an actual quotient with stored quotient values. The actual output signal level of the detectors is compared with stored output signal levels to determine size of the object. A size representative value determined for the object is compared with a preset lower threshold level. An alarm signal is produced if the size representative value lies above the lower threshold level of the size of the object. Independent claims are also included for the following: (1) a passive infrared detector (2) a movement alarm system.