GUARD SYSTEM AND PROCESS BASED ON OPTICAL FIBER TECHNOLOGY, WITH LOCALIZATION OF UNAUTHORIZED INTERVENTION IN THE GUARD SYSTEM

• Main Authors: ENĂCHESCU MARIAN, JDERU ALEXANDRU-ALIN, DOROBANŢU DOREL, COJOCARU ION, BORŞCIOV VICTOR, VERLAN VICTOR, CULEAC ION, IOVU MIHAIL
• Format: Patent
• Language: English; Romanian
• Published: 28.06.2024
• Subjects: ALARM SYSTEMS; ORDER TELEGRAPHS; PHYSICS; SIGNALLING; SIGNALLING OR CALLING SYSTEMS

The invention relates to a guard system and to a process implemented by the said system, meant to protect objects or individual rooms against unauthorized interventions. According to the invention, the system comprises a multi-mode optical fiber (1) connected to a source (3) of coherent light, by means of a beam divider (5), a photo-receiver (6) and a module (8) for shaping the alarm signal, where the photo-receiver (6) is positioned in the remote field, at the output from the optical fiber (1) and it is represented by a CCD matrix for recording, in continuous field, at a preset frequency of F frames per second, the speckle image from the remote field of the optical fiber, and the module (8) of shaping the alarm signal consists of a PC provided with adequate image processing software, as well as a second reference optical fiber (2), placed in immediate contact and parallel with the first optical fiber (1), having, in its turn, a CCD receiver (7) in the remote field, connected to the PC, the second optical fiber (2) being connected to the same source (3) of coherent light by means of the mentioned beam divider (5). The claimed process comprises: - forming, in the first optical fiber (1), a distribution of the propagation modes for which the output signal (S) is proportional with the distance (L) from the fiber input end, with the deformation force (P) which acts upon the lateral fiber surface and with a proportionality coefficient (k), - forming, in the second optical fiber (2), a distribution of the modes for which the output signal (S) depends on the deformation force (P) and on a proportionality coefficient (k) and it does not depend on the distance (L) from the fiber input end, - calibrating the system by determining the alarm system as a ratio U=S/S=kL, where k=k1/k2, - determining the intrusion place as L=Uxkand displaying the same on a display device.