Sensing system, sensing device, and sensing method

Abstract

A sensing system according to the present disclosure comprises: optical fiber (10) installed in a predetermined area; a communication unit (20) that inputs pulsed light to the optical fiber (10) and receives, from the optical fiber (10), backscattered light of the pulsed light; and an identification unit (30) that identifies a normal state of the predetermined area on the basis of vibration information representing the vibration intensity or vibration frequency per unit time contained in the backscattered light at each position on the optical fiber (10).

Description

Sensing system, sensing device, and sensing method

[0001] The present disclosure relates to a sensing system, a sensing device, and a sensing method.

[0002] In recent years, development has been progressing on a technology called optical fiber sensing, which uses optical fiber as a sensor. Optical fiber sensing makes it possible to detect abnormalities occurring around the optical fiber by detecting vibrations and sounds around the optical fiber.

[0003] An example of a technology for detecting abnormalities using optical fiber sensing is the technology disclosed in Patent Document 1. The technology disclosed in Patent Document 1 is a technology for detecting unauthorized construction. Specifically, the technology disclosed in Patent Document 1 identifies and stores vibration patterns that occur when construction work is performed using a combination of different construction models, stores the combinations of different construction models used in reported construction work, and uses this stored information to detect unauthorized construction work.

[0004] International Publication No. 2021 / 010251

[0005] However, the technology disclosed in Patent Document 1 identifies vibration patterns that occur during construction work, and since the location where abnormalities can be detected is limited to the construction site, there is a problem in that it is not possible to detect abnormalities in any area other than the construction site.

[0006] In view of the above-mentioned problems, an object of the present disclosure is to provide a sensing system, a sensing device, and a sensing method that can contribute to detecting anomalies in any area.

[0007] A sensing system according to one embodiment comprises an optical fiber laid in a predetermined area; a communication unit that inputs pulsed light into the optical fiber and receives backscattered light corresponding to the pulsed light from the optical fiber; and an identification unit that identifies the normal state of the predetermined area based on vibration information contained in the backscattered light that represents the vibration intensity or vibration frequency per unit time at each position on the optical fiber.

[0008] A sensing device according to one embodiment includes a communication unit that inputs pulsed light into an optical fiber laid in a specified area and receives backscattered light corresponding to the pulsed light from the optical fiber, and an identification unit that identifies the normal state of the specified area based on vibration information contained in the backscattered light that represents the vibration intensity or vibration frequency per unit time at each position on the optical fiber.

[0009] A sensing method according to one aspect is a sensing method using a sensing device, and includes a communication step of inputting pulsed light into an optical fiber laid in a predetermined area and receiving backscattered light corresponding to the pulsed light from the optical fiber, and a first identification step of identifying the normal state of the predetermined area based on vibration information contained in the backscattered light and representing vibration intensity or vibration frequency per unit time at each position on the optical fiber.

[0010] According to the above-described aspects, it is possible to provide a sensing system, a sensing device, and a sensing method that can contribute to detecting an abnormality in any area.

[0011] FIG. 1 is a diagram showing an example of the configuration of a sensing system according to embodiment 1. FIG. 2 is a diagram showing an example of vibration information under normal conditions according to embodiment 1. FIG. 3 is a flow diagram showing an example of a schematic operation flow of the sensing system according to embodiment 1. FIG. 4 is a diagram showing an example of the configuration of a sensing system according to embodiment 2. FIG. 5 is a flow diagram showing an example of a schematic operation flow of the sensing system according to embodiment 2. FIG. 6 is a diagram showing an example of the configuration of a sensing system according to embodiment 3. FIG. 7 is a diagram showing an example of the relationship between vibration information under normal conditions and a threshold value according to embodiment 3. FIG. 8 is a flow diagram showing an example of a schematic operation flow of the sensing system according to embodiment 3. FIG. 9 is a diagram showing an example of the configuration of a sensing system according to embodiment 4. FIG. 10 is a flow diagram showing an example of a schematic operation flow of the sensing system according to embodiment 4. FIG. 11 is a diagram showing an example of the configuration of a sensing system according to another embodiment. FIG. 12 is a block diagram showing an example of the hardware configuration of a computer that realizes a sensing device according to another embodiment.

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the following description and drawings have been omitted and simplified as appropriate for clarity of explanation. In addition, in the following drawings, the same elements are given the same reference numerals, and duplicate explanations are omitted as necessary.

[0013] First Embodiment First, a configuration example of a sensing system according to the first embodiment will be described with reference to Fig. 1. As shown in Fig. 1, the sensing system according to the first embodiment includes an optical fiber 10, a communication unit 20, and an identification unit 30. Note that Fig. 1 assumes that the communication unit 20 and the identification unit 30 are provided separately. The identification unit 30 may be provided in a device separate from the communication unit 20, or may be provided on the cloud.

[0014] The optical fiber 10 is laid in an area where an abnormality is desired to be detected. The optical fiber 10 may be installed in the air, buried underground, or may be partially installed in the air and the remaining portion buried underground. In the example of FIG. 1 , a portion of the optical fiber 10 is suspended from a utility pole 91, and the remaining portion is passed through an underground conduit 92. The optical fiber 10 may also be laid in the form of an optical fiber cable configured by covering the optical fiber 10. One end of the optical fiber 10 is connected to the communication unit 20.

[0015] The communication unit 20 transmits pulsed light to the optical fiber 10. Backscattered light is then generated as the pulsed light is transmitted through the optical fiber 10. The communication unit 20 receives the backscattered light from the optical fiber 10.

[0016] The identification unit 30 is capable of calculating the position on the optical fiber 10 where the backscattered light occurred (the length of the optical fiber 10 from the communication unit 20) based on the time difference between the time when the communication unit 20 transmitted pulsed light to the optical fiber 10 and the time when the communication unit 20 received the backscattered light from the optical fiber 10.

[0017] In the optical fiber 10, vibrations occur in the aerial portion due to, for example, exposure to rain or wind. Also, vibrations occur in the portion buried underground due to, for example, vehicles running on the road directly above. When vibrations occur in the optical fiber 10, the characteristics (for example, wavelength) of the backscattered light transmitted through the optical fiber 10 change.

[0018] Therefore, by analyzing the characteristics of the backscattered light, the identifying unit 30 can calculate the vibration intensity or vibration frequency at the position on the optical fiber 10 where the backscattered light is generated. Furthermore, the identifying unit 30 can calculate the vibration intensity or vibration frequency per unit time at each position on the optical fiber 10 based on the time course of the vibration intensity or vibration frequency at each position on the optical fiber 10.

[0019] Therefore, by analyzing the characteristics of the backscattered light, the identifying unit 30 can acquire vibration information that represents the vibration intensity or vibration frequency per unit time at each position on the optical fiber 10. In other words, the vibration information is contained in the backscattered light, and the identifying unit 30 can acquire the vibration information contained in the backscattered light by analyzing the characteristics of the backscattered light.

[0020] Therefore, the identification unit 30 obtains vibration information of the area where the optical fiber 10 is laid under normal conditions by analyzing the backscattered light received by the communication unit 20 during normal times when no abnormalities occur in the area where the optical fiber 10 is laid.

[0021] Fig. 2 shows an example of vibration information under normal conditions acquired by the identification unit 30. Fig. 2 shows an example in which the vibration information represents vibration intensity per unit time. In Fig. 2, the horizontal axis represents the position on the optical fiber 10 (the length of the optical fiber 10 from the communication unit 20), and the vertical axis represents vibration intensity per unit time. Specifically, in Fig. 2, the vertical axis represents the vibration intensity per unit time (e.g., about 30 seconds) averaged over several days (e.g., about one week).

[0022] The identifying unit 30 acquires vibration information such as that shown in Fig. 2 and, based on the vibration information, identifies the normal state of the area in which the optical fiber 10 is laid. That is, the identifying unit 30 identifies the state represented by the vibration information such as that shown in Fig. 2 as the normal state.

[0023] Next, an example of a schematic operation flow of the sensing system according to the first embodiment will be described with reference to Fig. 3. As shown in Fig. 3, first, the communication unit 20 transmits pulsed light to the optical fiber 10 (step S11), and receives backscattered light corresponding to the pulsed light from the optical fiber 10 (step S12).

[0024] Then, the identification unit 30 analyzes the characteristics of the backscattered light to obtain vibration information contained in the backscattered light that represents the vibration intensity or vibration frequency per unit time at each position on the optical fiber 10, and based on the obtained vibration information, identifies the normal state of the area in which the optical fiber 10 is laid (step S13).

[0025] As described above, according to the first embodiment, the communication unit 20 transmits pulsed light to the optical fiber 10 and receives backscattered light corresponding to the pulsed light from the optical fiber 10. The identification unit 30 identifies the normal state of the area in which the optical fiber 10 is laid, based on vibration information that is included in the backscattered light and that indicates the vibration intensity or vibration frequency per unit time at each position on the optical fiber 10.

[0026] As a result, when detecting an abnormality in any area where the optical fiber 10 is laid, it is possible to detect the abnormality by utilizing the normal state specified for that area, which can contribute to the detection of an abnormality in any area.

[0027] Second Embodiment Next, with reference to FIG. 4, a configuration example of a sensing system according to a second embodiment will be described.

[0028] As shown in FIG. 4, the sensing system according to the second embodiment differs from the configuration of the first embodiment shown in FIG. 1 in that an abnormality detection unit 40 is added.

[0029] As described above, the identifying unit 30 identifies the normal state of the area where the optical fiber 10 is laid. The normal state identified by the identifying unit 30 is stored in a memory (not shown) or the like. Furthermore, the identifying unit 30 also identifies the current state of the area where the optical fiber 10 is laid, based on the vibration information contained in the backscattered light.

[0030] If, as shown in Figure 4, large vibrations different from those under normal circumstances occur due to trees coming into contact with the optical fiber 10 due to a strong wind or the collapse of a utility pole 91, or road construction, the vibration information contained in the backscattered light will change, and the state identified by the identification unit 30 will also change.

[0031] Therefore, the abnormality detection unit 40 compares the current state of the area where the optical fiber 10 is laid with the normal state, and based on the comparison result, detects whether an abnormality is currently occurring in the area where the optical fiber 10 is laid. For example, if the vibration information represents vibration intensity per unit time, the abnormality detection unit 40 may determine that an abnormality has occurred at any position on the optical fiber 10 when the vibration intensity per unit time at that position is greater than or equal to a certain value compared to normal.

[0032] Next, an example of a schematic flow of operation of the sensing system according to the second embodiment will be described with reference to Fig. 5. Here, the operation will be described when detecting an abnormality in an area where the optical fiber 10 is laid, in a situation where the normal state of the area has already been identified and the normal state has already been stored in a memory or the like (not shown).

[0033] As shown in FIG. 5, first, the communication unit 20 transmits pulsed light to the optical fiber 10 (step S21), and receives backscattered light corresponding to the pulsed light from the optical fiber 10 (step S22).

[0034] Next, the identification unit 30 analyzes the characteristics of the backscattered light to obtain vibration information contained in the backscattered light that represents the vibration intensity or vibration frequency per unit time at each position on the optical fiber 10, and based on the obtained vibration information, identifies the current state of the area in which the optical fiber 10 is laid (step S23).

[0035] Thereafter, the abnormality detection unit 40 compares the current state of the area where the optical fiber 10 is laid with the normal state, and based on the comparison result, detects whether an abnormality is currently occurring in the area where the optical fiber 10 is laid (step S24).

[0036] As described above, according to the second embodiment, the identifying unit 30 identifies in advance the normal state of the area where the optical fiber 10 is laid, based on the vibration information contained in the backscattered light. Then, the identifying unit 30 identifies the current state of the area where the optical fiber 10 is laid, based on the vibration information contained in the backscattered light. The abnormality detection unit 40 detects an abnormality in the area where the optical fiber 10 is laid by comparing the current state of the area where the optical fiber 10 is laid with the normal state. This makes it possible to detect an abnormality in any area where the optical fiber 10 is laid.

[0037] Third Embodiment Next, with reference to FIG. 6, a configuration example of a sensing system according to a third embodiment will be described.

[0038] As shown in FIG. 6, the sensing system according to the third embodiment differs from the configuration of the second embodiment shown in FIG. 4 in that a threshold setting unit 50 is added.

[0039] As described above, the identifying unit 30 identifies the normal state of the area in which the optical fiber 10 is laid.

[0040] The threshold setting unit 50 sets a threshold according to the normal state of the area where the optical fiber 10 is laid. For example, if the vibration information represents vibration intensity per unit time, the threshold may be set to a value that is about 1.5 times the vibration intensity at that position in the normal vibration information for each position on the optical fiber 10. The threshold set by the threshold setting unit 50 is stored in a memory or the like (not shown).

[0041] 7 shows an example of the relationship between the vibration information under normal conditions acquired by the identification unit 30 and the threshold value set by the threshold value setting unit 50. In FIG. 7, the horizontal and vertical axes are the same as those in FIG. 2.

[0042] The identification unit 30 also identifies the current state of the area where the optical fiber 10 is laid, based on the vibration information contained in the backscattered light. The abnormality detection unit 40 compares the current state of the area where the optical fiber 10 is laid with a threshold, and detects whether an abnormality is currently occurring in the area where the optical fiber 10 is laid, based on the comparison result. For example, if the vibration information represents vibration intensity per unit time, the abnormality detection unit 40 may determine that an abnormality has occurred at any position on the optical fiber 10 if the vibration intensity per unit time becomes greater than a threshold at that position.

[0043] Next, an example of a schematic flow of operation of the sensing system according to the third embodiment will be described with reference to Fig. 8. Here, the operation will be described when detecting an abnormality in an area where the optical fiber 10 is laid, in a situation where the threshold value for that area has already been set and stored in a memory or the like (not shown).

[0044] As shown in FIG. 8, first, steps S31 to S33 similar to steps S21 to S23 in FIG. 5 of the second embodiment are performed.

[0045] Thereafter, the abnormality detection unit 40 compares the current state of the area where the optical fiber 10 is laid with the threshold value, and based on the comparison result, detects whether an abnormality is currently occurring in the area where the optical fiber 10 is laid (step S34).

[0046] As described above, according to the third embodiment, the identifying unit 30 identifies in advance the normal state of the area where the optical fiber 10 is laid, based on the vibration information contained in the backscattered light, and the threshold setting unit 50 sets in advance a threshold value corresponding to the identified normal state. The identifying unit 30 then identifies the current state of the area where the optical fiber 10 is laid, based on the vibration information contained in the backscattered light. The abnormality detection unit 40 detects an abnormality in the area where the optical fiber 10 is laid by comparing the current state of the area where the optical fiber 10 is laid with the threshold value. This makes it possible to detect an abnormality in any area where the optical fiber 10 is laid.

[0047] Fourth Embodiment Next, with reference to FIG. 9, a configuration example of a sensing system according to a fourth embodiment will be described.

[0048] As shown in FIG. 9, the sensing system according to the fourth embodiment differs from the configuration of the third embodiment shown in FIG. 6 in that a notification unit 60 is added.

[0049] When the abnormality detection unit 40 determines that an abnormality has occurred in the area where the optical fiber 10 is laid, the notification unit 60 notifies a predetermined notification destination that an abnormality has occurred in that area. At this time, the notification unit 60 may notify the predetermined notification destination not only of the occurrence of an abnormality in the area where the optical fiber 10 is laid, but also of the location where the abnormality has occurred. The predetermined notification destination may be, for example, a terminal installed in a management center that manages the area where the optical fiber 10 is laid, a local government, the country, etc. Furthermore, the notification method may be, for example, a method of displaying a GUI (Graphical User Interface) screen on a display or monitor of the notification destination terminal, or a method of outputting a message by voice from a speaker of the notification destination terminal.

[0050] Next, an example of a schematic operation flow of the sensing system according to the fourth embodiment will be described with reference to Fig. 10. As shown in Fig. 10, first, steps S41 to S44 are performed, which are similar to steps S31 to S34 in Fig. 8 of the third embodiment described above. In step S44, if the abnormality detection unit 40 determines that an abnormality has occurred in the area where the optical fiber 10 is laid (Yes in step S44), the notification unit 60 notifies a predetermined notification destination that an abnormality has occurred (step S45).

[0051] As described above, according to the fourth embodiment, when the abnormality detection unit 40 determines that an abnormality has occurred in the area where the optical fiber 10 is laid, the notification unit 60 notifies a predetermined notification destination that an abnormality has occurred in the area. This makes it possible to notify a management center or the like that manages the area that an abnormality has occurred.

[0052] Furthermore, the notification unit 60 may notify a predetermined notification destination not only of the occurrence of an abnormality in the area where the optical fiber 10 is laid, but also of the location where the abnormality has occurred. This allows personnel at a management center or the like to quickly rush to the site where the abnormality has occurred. Other effects are the same as those of the third embodiment described above.

[0053] <Other Embodiments> In the first embodiment described above, the communication unit 20 and the identification unit 30 are provided separately, but the communication unit 20 and the identification unit 30 may be provided in the same device. Fig. 11 shows a configuration example of a sensing system in which the communication unit 20 and the identification unit 30 are provided inside a sensing device 70. Note that the sensing system shown in Fig. 11 may also add the anomaly detection unit 40, threshold setting unit 50, and notification unit 60 according to the second, third, and fourth embodiments described above inside the sensing device 70.

[0054] Furthermore, even in the same area where the optical fiber 10 is installed, the vibration state may fluctuate significantly over time. For example, the volume of vehicle traffic traveling on a road may differ between morning, noon, and night, and may also differ depending on the day of the week. Therefore, the identifying unit 30 may identify the normal state for each day of the week or time, and the threshold setting unit 50 may set a threshold. In this case, the abnormality detection unit 40 may detect an abnormality by comparing the current state with the threshold corresponding to the current day of the week or time.

[0055] Furthermore, abnormal vibrations may occur periodically for a short period of time in the area where the optical fiber 10 is installed. For example, the passing of a train at a railroad crossing or the warning sound of a crossing barrier do not last more than one minute. Therefore, the identifying unit 30, the abnormality detection unit 40, and the threshold setting unit 50 may only detect abnormalities in vibrations that last for a predetermined period of time or more. That is, the identifying unit 30 may remove vibrations that have not lasted for a predetermined period of time from the vibration information and identify the normal state or the current state based on the vibration information after the removal. In this case, the threshold setting unit 50 may set a threshold based on the normal state identified from the vibration information after the removal. Furthermore, the abnormality detection unit 40 may detect an abnormality by comparing the current state identified from the vibration information after the removal with the threshold set based on the vibration information after the removal.

[0056] Furthermore, in the area where the optical fiber 10 is laid, abnormal vibrations may occur irregularly. Therefore, the identifying unit 30, the abnormality detection unit 40, and the threshold setting unit 50 may learn vibration patterns of abnormal vibrations that occur irregularly and detect only vibrations other than the learned vibration patterns. That is, the identifying unit 30 may learn vibration patterns of abnormal vibrations that occur irregularly, extract only vibrations other than the learned vibration patterns from the vibration information, and identify the normal state or the current state based on the extracted vibration information. In this case, the threshold setting unit 50 may set a threshold based on the normal state identified from the extracted vibration information. Furthermore, the abnormality detection unit 40 may detect an abnormality by comparing the current state identified from the extracted vibration information with the threshold set based on the extracted vibration information.

[0057] <Hardware Configuration of Sensing Device According to Embodiment> Next, with reference to FIG. 12, an example of the hardware configuration of a computer 80 that realizes the sensing device 70 according to the above-described other embodiment (FIG. 11) will be described.

[0058] 12, a computer 80 includes a processor 81, a memory 82, a storage 83, an input / output interface (input / output I / F) 84, and a communication interface (communication I / F) 85. The processor 81, the memory 82, the storage 83, the input / output interface 84, and the communication interface 85 are connected by a data transmission path for transmitting and receiving data to and from each other.

[0059] The processor 81 is, for example, an arithmetic processing device such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit). The memory 82 is, for example, a memory such as a RAM (Random Access Memory) or a ROM (Read Only Memory). The storage 83 is, for example, a storage device such as a HDD (Hard Disk Drive), an SSD (Solid State Drive), or a memory card. The storage 83 may also be a memory such as a RAM or a ROM.

[0060] A program is stored in the storage 83. When the program is loaded into a computer, it includes a set of instructions (or software code) that causes the computer 80 to perform one or more functions of the sensing device 70 described above. The components of the sensing device 70 described above may be realized by the processor 81 reading and executing a program stored in the storage 83. Furthermore, the storage function of the sensing device 70 described above may be realized by the memory 82 or the storage 83.

[0061] The above-described programs may also be stored on non-transitory computer-readable media or tangible storage media. By way of example and not limitation, computer-readable media or tangible storage media include RAM, ROM, flash memory, SSD or other memory technologies, CD (Compact Disc)-ROM, DVD (Digital Versatile Disc), Blu-ray® disk or other optical disk storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage devices. The programs may also be transmitted on a transitory computer-readable medium or communication medium. By way of example and not limitation, transitory computer-readable media or communication media include electrical, optical, acoustic, or other forms of propagated signals.

[0062] The input / output interface 84 is connected to a display device 841, an input device 842, a sound output device 843, etc. The display device 841 is a device that displays a screen corresponding to drawing data processed by the processor 81, such as an LCD (Liquid Crystal Display), a CRT (Cathode Ray Tube) display, or a monitor. The input device 842 is a device that accepts operation inputs from an operator, such as a keyboard, a mouse, or a touch sensor. The display device 841 and the input device 842 may be integrated and realized as a touch panel. The sound output device 843 is a device that outputs sound corresponding to the sound data processed by the processor 81, such as a speaker.

[0063] The communication interface 85 transmits and receives data to and from an external device. For example, the communication interface 85 communicates with the external device via a wired communication path or a wireless communication path.

[0064] Although the present disclosure has been described above with reference to the embodiments, the present disclosure is not limited to the above-described embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present disclosure. For example, some or all of the above-described embodiments may be used in combination with each other.

[0065] Furthermore, some or all of the above-described embodiments can be described as, but are not limited to, the following supplementary notes. (Supplementary Note 1) A sensing system comprising: an optical fiber laid in a predetermined area; a communication unit that inputs pulsed light into the optical fiber and receives backscattered light in response to the pulsed light from the optical fiber; and an identification unit that identifies a normal state of the predetermined area based on vibration information contained in the backscattered light and that indicates vibration intensity or vibration frequency per unit time at each position on the optical fiber. (Supplementary Note 2) The sensing system according to Supplementary Note 1 further comprises an abnormality detection unit, wherein the identification unit identifies a current state of the predetermined area based on the vibration information, and the abnormality detection unit detects an abnormality in the predetermined area by comparing the current state of the predetermined area with a normal state. (Supplementary Note 3) The sensing system according to Supplementary Note 1, further comprising: an abnormality detection unit; and a threshold setting unit that sets a threshold according to the normal state of the predetermined area, wherein the identification unit identifies the current state of the predetermined area based on the vibration information, and the abnormality detection unit detects an abnormality in the predetermined area by comparing the current state of the predetermined area with the threshold. (Supplementary Note 4) The sensing system according to Supplementary Note 3, wherein the identification unit identifies the normal state of the predetermined area for each day of the week or each hour of the day, the threshold setting unit sets the threshold for each day of the week or each hour of the day, and the abnormality detection unit detects an abnormality in the predetermined area by comparing the current state of the predetermined area with the threshold according to the current day of the week or each hour of the day. (Supplementary Note 5) The sensing system according to Supplementary Note 2 or 3, wherein the identification unit removes vibrations that have not continued for more than a predetermined time from the vibration information, and identifies the normal state and the current state of the predetermined area based on the vibration information after removal. (Supplementary Note 6) The sensing system according to Supplementary Note 2 or 3, wherein the identification unit learns vibration patterns of abnormal vibrations that occur irregularly, extracts vibrations other than the learned vibration patterns from the vibration information, and identifies the normal state and the current state of the specified area based on the extracted vibration information.(Supplementary Note 7) The sensing system according to Supplementary Note 2 or 3, further comprising an alarm unit that, when the anomaly detection unit determines that an abnormality has occurred in the predetermined area, notifies a predetermined notification destination that an abnormality has occurred in the predetermined area. (Supplementary Note 8) A sensing device comprising: a communication unit that inputs pulsed light into an optical fiber laid in the predetermined area and receives backscattered light from the optical fiber in response to the pulsed light; and an identification unit that identifies a normal state of the predetermined area based on vibration information contained in the backscattered light and that represents vibration intensity or vibration frequency per unit time at each position on the optical fiber. (Supplementary Note 9) The sensing device according to Supplementary Note 8, further comprising an anomaly detection unit, wherein the identification unit identifies a current state of the predetermined area based on the vibration information, and the anomaly detection unit detects an abnormality in the predetermined area by comparing the current state of the predetermined area with its normal state. (Supplementary Note 10) The sensing device according to Supplementary Note 8, further comprising: an abnormality detection unit; and a threshold setting unit that sets a threshold according to the normal state of the predetermined area, wherein the identification unit identifies the current state of the predetermined area based on the vibration information, and the abnormality detection unit detects an abnormality in the predetermined area by comparing the current state of the predetermined area with the threshold. (Supplementary Note 11) The sensing device according to Supplementary Note 10, wherein the identification unit identifies the normal state of the predetermined area for each day of the week or each hour of the day, the threshold setting unit sets the threshold for each day of the week or each hour of the day, and the abnormality detection unit detects an abnormality in the predetermined area by comparing the current state of the predetermined area with the threshold according to the current day of the week or each hour of the day. (Supplementary Note 12) The sensing device according to Supplementary Note 9 or 10, wherein the identification unit removes vibrations that have not continued for more than a predetermined time from the vibration information, and identifies the normal state and the current state of the predetermined area based on the vibration information after removal. (Supplementary Note 13) The sensing device according to Supplementary Note 9 or 10, wherein the identification unit learns vibration patterns of abnormal vibrations that occur irregularly, extracts vibrations other than the learned vibration patterns from the vibration information, and identifies the normal state and the current state of the specified area based on the extracted vibration information.(Supplementary Note 14) The sensing device according to Supplementary Note 9 or 10, further comprising a notification unit that, when the anomaly detection unit determines that an abnormality has occurred in the predetermined area, notifies a predetermined notification destination that an abnormality has occurred in the predetermined area. (Supplementary Note 15) A sensing method using a sensing device, comprising: a communication step of inputting pulsed light into an optical fiber laid in the predetermined area and receiving backscattered light from the optical fiber in response to the pulsed light; and a first identification step of identifying a normal state of the predetermined area based on vibration information contained in the backscattered light and representing vibration intensity or vibration frequency per unit time at each position on the optical fiber. (Supplementary Note 16) The sensing method according to Supplementary Note 15, further comprising: a second identification step of identifying a current state of the predetermined area based on the vibration information; and an abnormality detection step of detecting an abnormality in the predetermined area by comparing the current state of the predetermined area with a normal state. (Supplementary Note 17) The sensing method according to Supplementary Note 15, further comprising: a threshold setting step of setting a threshold according to the normal state of the predetermined area, a second specifying step of specifying the current state of the predetermined area based on the vibration information, and an abnormality detection step of detecting an abnormality in the predetermined area by comparing the current state of the predetermined area with the threshold. (Supplementary Note 18) The sensing method according to Supplementary Note 17, wherein the first specifying step specifies the normal state of the predetermined area for each day of the week or each hour of the day, the threshold setting step sets the threshold for each day of the week or each hour of the day, and the abnormality detection step detects an abnormality in the predetermined area by comparing the current state of the predetermined area with the threshold according to the current day of the week or each hour of the day. (Supplementary Note 19) The sensing method described in Supplementary Note 16 or 17, wherein in the first identification step, vibrations that have not continued for a predetermined time or longer are removed from the vibration information, and the normal state of the specified area is identified based on the vibration information after removal; and in the second identification step, vibrations that have not continued for a predetermined time or longer are removed from the vibration information, and the current state of the specified area is identified based on the vibration information after removal.(Supplementary Note 20) The sensing method according to Supplementary Note 16 or 17, further comprising a learning step of learning vibration patterns of abnormal vibrations that occur irregularly, wherein in the first specifying step, vibrations other than the vibration patterns learned in the learning step are extracted from the vibration information and a normal state of the predetermined area is specified based on the vibration information after extraction, and in the second specifying step, vibrations other than the vibration patterns learned in the learning step are extracted from the vibration information and a current state of the predetermined area is specified based on the vibration information after extraction. (Supplementary Note 21) The sensing method according to Supplementary Note 16 or 17, further comprising a reporting step of, when it is determined by the abnormality detection step that an abnormality has occurred in the predetermined area, reporting that an abnormality has occurred in the predetermined area to a predetermined reporting destination.

[0066] REFERENCE SIGNS LIST 10 Optical fiber 20 Communication unit 30 Identification unit 40 Abnormality detection unit 50 Threshold setting unit 60 Notification unit 70 Sensing device 80 Computer 81 Processor 82 Memory 83 Storage 84 Input / output interface 841 Display device 842 Input device 843 Sound output device 85 Communication interface 91 Utility pole 92 Underground conduit

Claims

1. An optical fiber laid in a predetermined area; a communication unit that inputs pulsed light into the optical fiber and receives backscattered light corresponding to the pulsed light from the optical fiber; and a determination unit that determines a normal state of the predetermined area based on vibration information that is included in the backscattered light and that indicates a vibration intensity or a vibration frequency per unit time at each position on the optical fiber. Sensing system.

2. An abnormality detection unit is further provided, The identification unit identifies a current state of the predetermined area based on the vibration information, The abnormality detection unit detects an abnormality in the specified area by comparing a current state of the specified area with a normal state of the specified area. The sensing system of claim 1 .

3. a communication unit that inputs pulsed light into an optical fiber laid in a predetermined area and receives backscattered light corresponding to the pulsed light from the optical fiber; and a determination unit that determines a normal state of the predetermined area based on vibration information that is included in the backscattered light and that indicates a vibration intensity or a vibration frequency per unit time at each position on the optical fiber. Sensing equipment.

4. An abnormality detection unit is further provided, The identification unit identifies a current state of the predetermined area based on the vibration information, The abnormality detection unit detects an abnormality in the specified area by comparing a current state of the specified area with a normal state of the specified area. The sensing device according to claim 3 .

5. An abnormality detection unit; A threshold setting unit that sets a threshold value according to a normal state of the predetermined area, The identification unit identifies a current state of the predetermined area based on the vibration information, The abnormality detection unit detects an abnormality in the specified region by comparing a current state of the specified region with the threshold value. The sensing device according to claim 3 .

6. The identification unit identifies a normal state of the predetermined area for each day of the week or each time of day, The threshold setting unit sets the threshold for each day of the week or each time of day, The abnormality detection unit detects an abnormality in the specified area by comparing a current state of the specified area with the threshold value corresponding to a current day of the week or time. The sensing device according to claim 5 .

7. the identifying unit removes from the vibration information any vibration that has not continued for a predetermined time or longer, and identifies a normal state and a current state of the predetermined area based on the vibration information after the removal. The sensing device according to claim 4 or 5.

8. the identification unit learns vibration patterns of abnormal vibrations that occur irregularly, extracts vibrations other than the learned vibration patterns from the vibration information, and identifies a normal state and a current state of the predetermined area based on the extracted vibration information. The sensing device according to claim 4 or 5.

9. and a notification unit that notifies a predetermined notification destination that an abnormality has occurred in the predetermined region when the abnormality detection unit determines that an abnormality has occurred in the predetermined region. The sensing device according to claim 4 or 5.

10. A sensing method using a sensing device, comprising: a communication step of inputting pulsed light into an optical fiber laid in a predetermined area and receiving backscattered light corresponding to the pulsed light from the optical fiber; a first determination step of determining a normal state of the predetermined area based on vibration information representing a vibration intensity or a vibration frequency per unit time at each position on the optical fiber, the vibration information being included in the backscattered light, Sensing method.