# US 12,181,336 B2 · Optical fiber sensing system, optical fiber sensing equipment, and underground action monitoring method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,181,336 B2 - Document ID: US12181336B2 - Status: Granted - Kind: B2 - Application number: 17/623,332 - Filed: 2019-07-05 - Published: 2022-12-08 - Granted: 2024-12-31 - Earliest claimed: 2019-07-05 - Assignees: NEC Corporation - Applicants: NEC Corporation - Inventors: Takashi Kojima - Web page: https://patentgrep.com/patent/US12181336B2 ## CPC - G01H 9/004: {using fibre optic sensors (light guides per se G02B6/00, acousto-optical devices specially adapted for gating or modulating in optical wave guides G02F1/125)} - G06V 20/52: Surveillance or monitoring of activities, e.g. for recognising suspicious objects (recognising microscopic objects G06V20/69) - G08B 13/16: Actuation by interference with mechanical vibrations in air or other fluid - G06F 2218/12: Classification; Matching - G01H: MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES - G06V: IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING - G08B: SIGNALLING SYSTEMS, e.g. PERSONAL CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract An optical fiber sensing system according to the present disclosure includes an optical fiber (10A) configured to detect a vibration in underground, an acquisition unit (21) configured to acquire, from the optical fiber (10A), an optical signal on which the vibration detected by the optical fiber (10A) is superimposed, and an identifying unit (22) configured to identify a suspicious action in the underground based on a vibration pattern included in the optical signal acquired by the acquisition unit (21). ## Claims ### Claim 1 An optical fiber sensing system comprising: an optical fiber configured to detect a vibration in underground; an acquisition unit configured to acquire, from the optical fiber, an optical signal on which the vibration detected by the optical fiber is superimposed; an identifying unit configured to identify a suspicious action in the underground based on a vibration pattern included in the optical signal acquired by the acquisition unit; and a storage unit configured to store in advance a vibration pattern of the vibration generated when the suspicious action occurs in the underground as a first vibration pattern, wherein the identifying unit is configured to determine, when the vibration pattern included in the optical signal acquired by the acquisition unit matches the first vibration pattern, the suspicious action corresponding to the first vibration pattern has occurred in the underground. ### Claim 2 (depends on 1) The optical fiber sensing system according to claim 1, wherein the identifying unit is configured to determine that the suspicious action has occurred in the underground when a periodic vibration is detected in the vibration pattern included in the optical signal and strength of the vibration gradually increases. ### Claim 3 (depends on 2) The optical fiber sensing system according to claim 2, wherein at least a part of the optical fiber is disposed in the underground, and the acquisition unit is configured to acquire, from the optical fiber, an optical signal on which a vibration detected by the part of the optical fiber disposed in the underground is superimposed. ### Claim 4 (depends on 1) The optical fiber sensing system according to claim 1, wherein the storage unit is configured to store in advance a vibration pattern of a vibration generated when the underground is in a normal state as a second vibration pattern, and the identifying unit is configured to determine, when the vibration pattern included in the optical signal acquired by the acquisition unit is different from the second vibration pattern and matches the first vibration pattern, that the suspicious action corresponding to the first vibration pattern has occurred in the underground. ### Claim 5 (depends on 1) The optical fiber sensing system according to claim 1, wherein the optical fiber includes a first optical fiber disposed in the underground and a second optical fiber disposed on ground, the acquisition unit is configured to acquire, from the first optical fiber, an optical signal on which a vibration detected by the first optical fiber is superimposed, and acquire, from the second optical fiber, an optical signal on which a vibration detected by the second optical fiber is superimposed, and the identifying unit is configured to determine, when the vibration pattern included in the optical signal acquired from the first optical fiber by the acquisition unit includes vibration strength greater than that of the vibration pattern included in the optical signal acquired from the second optical fiber by the acquisition unit, and the vibration pattern included in the optical signal acquired from the first optical fiber by the acquisition unit matches the first vibration pattern, that the suspicious action corresponding to the first vibration pattern has occurred in the underground. ### Claim 6 (depends on 1) The optical fiber sensing system according to claim 1, further comprising: a camera configured to be capable of capturing a camera image of the ground; an image acquisition unit configured to acquire the camera image captured by the camera; and an image processing unit configured to detect the suspicious action from the camera image, wherein the identifying unit is configured to determine, when the vibration pattern included in the optical signal acquired by the acquisition unit matches the first vibration pattern, and the image processing unit cannot detect the suspicious action, that the suspicious action corresponding to the first vibration pattern has occurred in the underground. ### Claim 7 (depends on 1) The optical fiber sensing system according to claim 1, further comprising: a position identifying unit configured to identify a position where the suspicious action identified by the identifying unit has occurred based on the vibration pattern included in the optical signal acquired by the acquisition unit. ### Claim 8 An optical fiber sensing equipment comprising: an acquisition unit configured to acquire an optical signal on which a vibration detected by an optical fiber is superimposed from the optical fiber for detecting the vibration in underground; an identifying unit configured to identify a suspicious action in the underground based on a vibration pattern included in the optical signal acquired by the acquisition unit; and a storage unit configured to store in advance a vibration pattern of the vibration generated when the suspicious action occurs in the underground as a first vibration pattern, wherein the identifying unit is configured to determine, when the vibration pattern included in the optical signal acquired by the acquisition unit matches the first vibration pattern, the suspicious action corresponding to the first vibration pattern has occurred in the underground. ### Claim 9 (depends on 8) The optical fiber sensing equipment according to claim 8, wherein the storage unit is configured to store in advance a vibration pattern of a vibration generated when the underground is in a normal state as a second vibration pattern, and the identifying unit is configured to determine, when the vibration pattern included in the optical signal acquired by the acquisition unit is different from the second vibration pattern and matches the first vibration pattern, that the suspicious action corresponding to the first vibration pattern has occurred in the underground. ### Claim 10 An underground action monitoring method performed by an optical fiber sensing system, the underground action monitoring method comprising: detecting, by an optical fiber, a vibration in underground; acquiring, from the optical fiber, an optical signal on which the vibration detected by the optical fiber is superimposed; identifying a suspicious action in the underground based on a vibration pattern included in the optical signal acquired in the acquiring; and storing in advance a vibration pattern of the vibration generated when the suspicious action occurs in the underground as a first vibration pattern, wherein in the identifying, when the vibration pattern included in the optical signal acquired in the acquiring matches the first vibration pattern, it is determined that the suspicious action corresponding to the first vibration pattern has occurred in the underground. ### Claim 11 (depends on 10) The underground action monitoring method according to claim 10, wherein in the storing, a vibration pattern of a vibration generated when the underground is in a normal state is stored in advance as a second vibration pattern, and in the identifying, when the vibration pattern included in the optical signal acquired in the acquiring is different from the second vibration pattern and matches the first vibration pattern, it is determined that the suspicious action corresponding to the first vibration pattern has occurred in the underground. ### Claim 12 (depends on 10) The underground action monitoring method according to claim 10, further comprising: acquiring a camera image captured by a camera capable of capturing the camera image of the ground; and detecting the suspicious action from the camera image, wherein in the identifying, when the vibration pattern included in the optical signal acquired in the acquiring matches the first vibration pattern, and the suspicious action cannot be detected in the acquiring of the camera image, it is determined that the suspicious action corresponding to the first vibration pattern has occurred in the underground.