Information processing device, method, and program

Abstract

Provided are an information processing device, a method, and a program for inhibiting erroneous detection in detecting disconnection of an optical fiber. The information processing device comprises: an acquisition means that acquires the vibration magnitude of an optical signal measured from an optical fiber; a classification means that classifies optical signals according to the vibration magnitude thereof; and a determination means that, on the basis of the classification result after the classification, determines a disconnection detection threshold for use in detecting a disconnection of the optical fiber. In that case, the determination means calculates an index value from the classification result, and determines the disconnection detection threshold on the basis of the index value.

Description

Information processing device, method, and program

[0001] The present disclosure relates to an information processing device, a method, and a program.

[0002] In recent years, there has been a rise in sensing technology using optical fibers as sensors. For example, optical fiber sensing technology has been proposed that detects vibrations in optical fibers installed on fences and other structures to monitor suspicious behavior and intrusions.

[0003] When performing the above-mentioned detection, wide-area sensing must be performed continuously. However, if a fault occurs in the optical fiber, sensing may be interrupted against the user's intention, and there may be areas or time periods where detection is not possible (the occurrence of a so-called security hole). Therefore, it is necessary to consider countermeasures in the event of a fault in the optical fiber.

[0004] Here, Patent Document 1 discloses a technology for detecting the occurrence of a fault in an optical fiber. The technology disclosed in Patent Document 1 receives reflected light of an optical signal transmitted to an optical fiber, and detects the occurrence of a fault in the optical fiber from a change in the intensity of the received reflected light.

[0005] JP 2015-089082 A

[0006] However, the technology disclosed in Patent Document 1 detects the occurrence of a fault in an optical fiber used for data communication. On the other hand, optical fiber sensing technology uses an optical signal that is weaker than the optical signal used for data communication, and therefore it is necessary to detect the magnitude of the weak vibration of the optical signal (signal strength). In particular, unlike data communication via optical fiber, the optical signal used in optical fiber sensing technology often generates noise due to disturbances such as wind and vibration. Therefore, there is a risk that a signal caused by noise may be mistakenly detected as a break.

[0007] In view of the above-described problems, an object of the present disclosure is to provide an information processing device, a method, and a program for suppressing false detections when detecting breaks in optical fibers.

[0008] The information processing device according to the present disclosure comprises an acquisition means for acquiring the magnitude of vibration of an optical signal measured from an optical fiber, a classification means for classifying the optical signals according to the magnitude of the vibration, and a determination means for determining a break detection threshold for detecting a break in the optical fiber based on the classification results.

[0009] The information processing method disclosed herein involves a computer acquiring the amplitude of vibration of an optical signal measured from an optical fiber, classifying the optical signal according to the amplitude of the vibration, and determining a break detection threshold for detecting a break in the optical fiber based on the classification results.

[0010] The information processing program according to the present disclosure causes a computer to execute an acquisition process for acquiring the magnitude of vibration of an optical signal measured from an optical fiber, a classification process for classifying the optical signal according to the magnitude of the vibration, and a determination process for determining a break detection threshold for detecting a break in the optical fiber based on the classification results.

[0011] According to the present disclosure, false detections can be suppressed when detecting breaks in optical fibers.

[0012] FIG. 1 is a block diagram showing a configuration of an information processing device according to the present disclosure. FIG. 2 is a flowchart showing a flow of an information processing method according to the present disclosure. FIG. 3 is a block diagram showing a configuration of an information processing device according to the present disclosure. FIG. 4 is a flowchart showing a flow of an information processing method according to the present disclosure. FIG. 5 is a block diagram showing an overall configuration of an optical fiber sensing system including an information processing device according to the present disclosure. FIG. 6 is a diagram for explaining the concept of a sensing range of an optical fiber in a stable state according to the present disclosure. FIG. 7 is a diagram for explaining the concept of the magnitude of vibration measured when an optical fiber is broken according to the present disclosure. FIG. 8 is a block diagram showing a configuration of an information processing device according to the present disclosure. FIG. 9 is a flowchart showing a flow of an optical fiber sensing process according to the present disclosure. FIG. 10 is a flowchart showing a flow of a break detection threshold determination process according to the present disclosure. FIG. 11 is a diagram for explaining the relationship between a histogram of vibration amplitude and the degree of separation according to the present disclosure. FIG. 12 is a diagram for explaining the effectiveness of a break detection threshold according to the present disclosure. FIG. 13 is a flowchart showing a flow of an abnormality detection process according to the present disclosure. FIG. 14 is a diagram showing an example of changes in each element of an abnormality recording array according to the present disclosure. FIG. 15 is a diagram showing an example of the position of an optical fiber, the magnitude of vibration, etc. when a break is detected according to the present disclosure. FIG. 16 is a diagram for explaining the relationship between the magnitude of vibration and the situation at the time of measurement according to the present disclosure. FIG. 17 is a flowchart showing a flow of a break detection threshold determination process according to the present disclosure.

[0013] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In each drawing, the same or corresponding elements are designated by the same reference numerals, and for clarity of explanation, duplicate explanations will be omitted as necessary.

[0014] (Embodiment 1) Fig. 1 is a block diagram showing the configuration of an information processing device 1. The information processing device 1 is a computer device for determining a signal strength threshold for detecting a break in an optical fiber. The information processing device 1 includes an acquisition unit 11, a classification unit 12, and a determination unit 13. The acquisition unit 11, the classification unit 12, and the determination unit 13 may be used as a means for acquiring information or data, a means for classifying, and a means for determining, respectively. It is assumed that the information processing device 1 is connected to a sensing device (not shown) for sensing the optical fiber to be measured.

[0015] The acquisition unit 11 acquires the amplitude of vibration of the optical signal measured from the optical fiber. The amplitude of vibration may also be referred to as signal intensity. For example, the sensing device may input an optical signal (pulsed light) into the optical fiber for sensing, and receive reflected light and scattered light generated as the pulsed light is transmitted through the optical fiber as returned light. The sensing device analyzes the received returned light to determine the signal intensity, i.e., the amplitude of vibration of the optical signal. Therefore, it can be said that the sensing device senses the optical fiber and measures the amplitude of vibration of the optical signal. Then, the acquisition unit 11 acquires the amplitude of vibration of the optical signal from the sensing device. Alternatively, the information processing device 1 may have some or all of the functions of the sensing device.

[0016] The classifier 12 classifies the optical signals by vibration magnitude. Accordingly, the classifier 12 may generate statistical information such as the number of measurements (acquisitions) for each vibration magnitude in the measured optical signals. The statistical information may be, for example, distribution information of the vibration magnitude. In other words, the classifier 12 may be an updater that updates distribution information of the signal strength of the optical signals measured from the optical fiber based on the vibration magnitude acquired by the acquirer 11.

[0017] The determination unit 13 determines a disconnection detection threshold for detecting a disconnection in the optical fiber based on the classification result. The classification result may be, for example, distribution information of the amplitude of vibration in the measured optical signal.

[0018] 2 is a flowchart showing the flow of the information processing method. First, the acquisition unit 11 acquires the amplitude of vibration of an optical signal measured from an optical fiber (S1). Next, the classification unit 12 classifies the optical signals by amplitude of vibration (S2). Then, the determination unit 13 determines a break detection threshold for detecting a break in the optical fiber based on the classification results (S3).

[0019] In this way, the information processing device 1 determines the disconnection detection threshold using the classification results obtained by classifying the optical signal measured for a specific optical fiber by vibration magnitude. The classification results indicate the distribution of the vibration magnitude of the optical signal at various positions, various states (stable and disconnected), or the effective and ineffective sensing ranges of the optical fiber. Therefore, the information processing device 1 can determine the boundary value between a connected state of the optical fiber and a state that is disconnected or equivalent to a disconnection based on the classification results. Therefore, the information processing device 1 according to the present disclosure can reduce false detections when detecting a disconnection in the optical fiber.

[0020] The information processing device 1 includes a processor, a memory, and a storage device (not shown). The storage device stores a computer program that implements the process of the information processing method shown in FIG. 2 . The processor then loads the computer program from the storage device into the memory and executes the computer program. The processor thereby realizes the functions of the acquisition unit 11, classification unit 12, and determination unit 13.

[0021] Alternatively, each component of the information processing device 1 may be realized by dedicated hardware. Furthermore, some or all of the components of each device may be realized by general-purpose or dedicated circuits, processors, etc., or a combination thereof. These may be configured by a single chip, or by multiple chips connected via a bus. Some or all of the components of each device may be realized by a combination of the above-mentioned circuits, etc., and a program. Furthermore, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an FPGA (Field-Programmable Gate Array), a quantum processor (quantum computer control chip), etc., may be used as the processor.

[0022] Furthermore, when some or all of the components of the information processing device 1 are realized by multiple information processing devices, circuits, etc., the multiple information processing devices, circuits, etc. may be centrally or distributed. For example, the information processing devices, circuits, etc. may be realized as a client-server system, a cloud computing system, or the like, in which they are connected via a communication network. Furthermore, the functions of the information processing device 1 may be provided in a SaaS (Software as a Service) format.

[0023] (Embodiment 2) Fig. 3 is a block diagram showing the configuration of an information processing device 1a. The information processing device 1a is a computer device for determining a signal strength threshold for detecting a break in an optical fiber. The information processing device 1a includes an acquisition unit 11a, a classification unit 12a, and a determination unit 13a. The acquisition unit 11a, the classification unit 12a, and the determination unit 13a may be used as a means for acquiring information or data, a means for classifying, and a means for determining, respectively. It is assumed that the information processing device 1a is connected to the sensing device for sensing the optical fiber to be measured.

[0024] The acquiring unit 11a acquires the amplitude of vibration of the plurality of optical signals measured from the optical fiber. The amplitude of vibration may also be called signal intensity. For example, the sensing device may sense the optical fiber to measure the amplitude of vibration of the plurality of optical signals. The acquiring unit 11a then acquires the amplitude of vibration of the plurality of optical signals from the sensing device. Alternatively, the information processing device 1a may have some or all of the functions of the sensing device.

[0025] The classification unit 12a classifies each piece of information about a plurality of optical signals into one of a plurality of vibration ranges based on the magnitude of the vibration. The information about the optical signal may include information identifying the incident or received optical signal, the time of incident or reception, and position information (measurement point) within the optical fiber measured by the optical signal. The vibration range is a range of signal strength. Therefore, the classification unit 12a may calculate the frequency of the optical signals classified into each vibration range. Furthermore, the vibration range is a range of numerical values ​​of the magnitude of the vibration. Note that the vibration range may be the smallest unit of the measurement value of the signal strength measured from the optical signal.

[0026] The determination unit 13 a determines a disconnection detection threshold for detecting a disconnection in the optical fiber based on the classification result, which may be, for example, a frequency distribution for each vibration range in the measured optical signals.

[0027] 4 is a flowchart showing the flow of the information processing method. First, the acquisition unit 11a acquires the amplitudes of vibrations of multiple optical signals measured from an optical fiber (S1a). Next, the classification unit 12a classifies each piece of information about the multiple optical signals into one of multiple vibration ranges based on the amplitude of vibration (S2a). Then, the determination unit 13a determines a break detection threshold for detecting a break in the optical fiber based on the classification results (S3a).

[0028] In this way, the information processing device 1a determines a disconnection detection threshold using a classification result that classifies the amplitudes of vibrations of multiple optical signals measured for a specific optical fiber into multiple vibration ranges. The classification result indicates the distribution of vibration ranges of the amplitudes of vibrations of optical signals at various positions, various states (stable and disconnected), or valid and invalid sensing ranges of the optical fiber. Therefore, the information processing device 1a can determine the boundary value between a connected state of the optical fiber and a state that is disconnected or equivalent to a disconnection based on the classification result. Therefore, the information processing device 1a according to the present disclosure can reduce false detections when detecting a disconnection in the optical fiber.

[0029] The information processing device 1a includes a processor, a memory, and a storage device (not shown). The storage device stores a computer program that implements the process of the information processing method shown in FIG. 4, for example. The processor then loads the computer program from the storage device into the memory and executes the computer program. This allows the processor to implement the functions of the acquisition unit 11a, classification unit 12a, and determination unit 13a.

[0030] In addition, the information processing device 1a may be realized in various forms, similar to the information processing device 1 described above.

[0031] (Embodiment 3) In this embodiment 3, we will explain the case where the break detection threshold is determined by obtaining signal strength (one or more measurement results) at multiple measurement points (including the effective sensing range and ineffective sensing range) of the optical fiber.

[0032] 5 is a block diagram showing the overall configuration of an optical fiber sensing system 1000 including an information processing device 100. The optical fiber sensing system 1000 is an intrusion detection system that detects vibrations of an optical fiber 21 installed on a fence or the like, and detects suspicious behavior or intrusion by a person U.

[0033] The optical fiber sensing system 1000 includes an optical fiber 21, a sensing device 22, a camera 23, an external system 24, and an information processing device 100. The optical fiber 21 is connected to the sensing device 22. The optical fiber 21 is a sensing optical fiber that is redundantly laid in a monitoring area. The sensing device 22, the camera 23, the external system 24, and the information processing device 100 are each connected to each other so as to be able to communicate with each other via a network N. Here, the network N is a wired and wireless communication line network.

[0034] The sensing device 22 performs sensing on the optical fiber 21. The sensing device 22 transmits measurement results of a plurality of optical signals received from the optical fiber 21 by sensing to the information processing device 100 via the network N. The measurement results include information about the optical signals described above. The sensing device 22 is realized, for example, using a distributed acoustic sensor (DAS). For example, a single DAS may be capable of monitoring the optical fiber 21 up to 100 km. Furthermore, the DAS can detect the optical fiber 21 with a detection accuracy of approximately 2 to 10 m. Note that, in the present disclosure, the sensing method itself for the optical fiber 21 is not an essential item, and therefore a detailed description of the sensing method will be omitted.

[0035] The camera 23 is an imaging device that captures images of the monitored area. The camera 23 transmits the captured images to the information processing device 100 via the network N. The external system 24 may include an alert management system or a video management system. The external system 24 operates in cooperation with the sensing device 22, the camera 23, and the information processing device 100 via the network N. For example, when the external system 24 detects an intrusion of a person U into the monitored area or detects a break in the optical fiber 21, it notifies the administrator's terminal or the like of this via the network N.

[0036] The information processing device 100 is an example of the information processing device 1 or 1a described above. The information processing device 100 is a computer device that performs at least a process of determining a disconnection detection threshold for the optical fiber 21, a process of setting a sensing range, and a process of detecting an abnormality. The information processing device 100 may be realized as a computer system including a plurality of computers. A detailed configuration of the information processing device 100 will be described later.

[0037] Here, the optical fiber sensing system 1000 uses, for example, an optical fiber sensing technology based on OTDR (Optical Time Domain Reflectometry). OTDR is a method for continuously measuring bending loss and splice loss of an optical fiber by receiving and analyzing Rayleigh scattered light generated when an optical pulse is incident on one end of the optical fiber. In OTDR optical fiber sensing technology, the threshold value for detecting events such as a break in the optical fiber from the signal strength is usually set based on the experience of the engineer. Therefore, there is a problem in that it is difficult to determine what value should be set as the threshold value for the signal strength (vibration magnitude) for detecting a break in the optical fiber. In particular, intrusion detection systems use optical signals that are weaker than the optical signals used for communication to detect the magnitude of weak vibrations in the optical signal. Therefore, when applied to intrusion detection systems, the optical signals measured by optical fiber sensing technology often suffer from noise due to disturbances such as wind and vibration, unlike ordinary optical fiber communications. Therefore, if the threshold value is set too low, there is a risk that a break in the optical fiber may be erroneously detected.

[0038] FIG. 6 is a diagram illustrating the concept of the sensing range of an optical fiber in a stable state. The horizontal axis represents the distance from the optical signal transmission source of the sensing device 22. The vertical axis represents the magnitude of vibration (signal strength) of the optical signal measured by the sensing device 22. The range from the transmission source to a predetermined distance is inside the sensing device 22, and is therefore a sensing invalid range 31. The sensing invalid range 31 exists because the vibration of the measured reflected light is excessive. The range from the transmission source to the end of the optical fiber 21 is a sensing invalid range 32. The sensing invalid range 32 exists because the vibration of the measured reflected light is excessive, similar to the sensing invalid range 31. Therefore, the sensing effective range 30 of the optical fiber 21 in a stable state is the distance from the transmission source of the optical fiber 21 between the sensing invalid range 31 and the sensing invalid range 32.

[0039] 7 is a diagram illustrating the concept of the magnitude of vibration measured when an optical fiber is broken. First, a measurement value 41 when vibration occurs does not reach the magnitude of vibration in the sensing invalid ranges 31 and 32. Here, "when vibration occurs" refers to a case where the optical fiber 21 vibrates due to external disturbances such as wind or vibration, or a person U swinging against the fence. On the other hand, a measurement value 42 when the optical fiber 21 is broken has a characteristic that it is measured as if a large vibration has occurred due to the break. Then, a measurement value 42 in the range beyond the position where the optical fiber 21 is broken can be equivalent to the magnitude of vibration in the sensing invalid ranges 31 and 32. Therefore, the technology disclosed herein utilizes this characteristic to determine the break detection threshold.

[0040] 8 is a block diagram showing the configuration of the information processing device 100. The information processing device 100 includes an acquisition unit 111, a classification unit 112, a determination unit 113, a detection unit 114, and a notification unit 115. The acquisition unit 111, the classification unit 112, the determination unit 113, the detection unit 114, and the notification unit 115 may be used as a means for acquiring information or data, a means for classifying, a means for determining, a means for detecting, and a means for notifying, respectively.

[0041] The acquiring unit 111 is an example of the aforementioned acquiring unit 11 or 11 a. The acquiring unit 111 acquires the amplitudes of vibrations of a plurality of optical signals measured from a plurality of measurement points of the optical fiber 21, respectively.

[0042] The classification unit 112 is an example of the classification unit 12 or 12a described above. The classification unit 112 calculates statistical information on the vibration magnitude for each measurement point of each optical signal acquired by the acquisition unit 111. The statistical information may be, for example, an average value, but is not limited to this. The classification unit 112 then classifies the statistical information into multiple vibration ranges to generate a classification result. The classification unit 112 generates a histogram of the vibration ranges for the average value of the vibration magnitude for each measurement point. However, the classification result is not limited to a histogram. Here, the classification result includes the vibration magnitude of the optical signal measured in the sensing invalid range of the optical fiber. Therefore, even if the vibration magnitude of the optical signal is measured when the optical fiber is not actually broken, the measurement value in the sensing invalid range can be considered as the measurement value at the time of the optical fiber break. This allows the measurement result of the optical fiber in a stable state to be used to accurately determine the break detection threshold. This also reduces erroneous detection of a break in the optical fiber.

[0043] The determiner 113 is an example of the determiner 13 or 13a described above. The determiner 113 calculates an index value from the classification results and determines the disconnection detection threshold based on the index value. Here, the index value indicates which vibration magnitude is appropriate as a criterion for dividing the measured vibration magnitude into at least two or more groups. For example, when the classification results are divided into two groups, a separation degree, which increases as the degree of overlap between the groups decreases, can be used as the index value. Alternatively, the determiner 113 may calculate an index value indicating the degree of separation when multiple vibration ranges are divided into two groups from the classification results, and determine the disconnection detection threshold based on the index value. In this case, the index value may increase as the degree of overlap between the groups decreases when multiple vibration ranges are divided into two groups. Note that the index value is not limited to the above-described one. A value calculated to divide data into multiple groups in known cluster analysis, etc., may also be used. In this way, the above-described characteristics can be utilized by determining the disconnection detection threshold using the index value. In other words, the boundary between the magnitude of vibration of a normal optical signal or the magnitude of vibration of external disturbance noise measured in the effective sensing range when the optical fiber is in a stable state and the measurement results in the ineffective sensing range becomes clear, making it possible to accurately determine the break detection threshold.

[0044] Furthermore, it is desirable that the determination unit 113 determine the magnitude of vibration corresponding to an index value equal to or greater than a first value as the disconnection detection threshold. Alternatively, the determination unit 113 may determine the magnitude of vibration included in a vibration range corresponding to an index value equal to or greater than the first value as the disconnection detection threshold. Here, various values ​​can be calculated for the index value. Therefore, by setting the magnitude of vibration corresponding to a calculated index value equal to or greater than a predetermined first value as the disconnection detection threshold, a more appropriate disconnection detection threshold can be determined with high accuracy.

[0045] Furthermore, the determination unit 113 may determine the largest vibration magnitude among multiple vibration magnitudes corresponding to index values ​​equal to or greater than a first value as the disconnection detection threshold. Here, the vibration magnitudes corresponding to index values ​​equal to or greater than the first value can vary. It can be said that the vibration magnitudes corresponding to index values ​​equal to or greater than the first value are relatively large. Therefore, by determining the largest vibration magnitude among the vibration magnitudes identified when the index value is equal to or greater than the first value as the disconnection detection threshold, the disconnection detection threshold can be determined with high accuracy.

[0046] Alternatively, the determination unit 113 preferably determines, as the disconnection detection threshold, a vibration magnitude that is greater than the median of multiple vibration magnitudes corresponding to index values ​​equal to or greater than a first value and smaller than the vibration magnitude that can be measured when the optical fiber is broken. Here, the index values ​​in the set of multiple vibration ranges can take various forms. Multiple vibration ranges can correspond to index values ​​equal to or greater than the first value. Furthermore, the vibration range corresponding to an index value equal to or greater than the first value can be considered to have a relatively large vibration magnitude (signal strength) among the set of (measured and classified) vibration ranges. Therefore, a lower limit value of the range for determining the disconnection detection threshold that is greater than the median of multiple vibration magnitudes corresponding to index values ​​equal to or greater than the first value can more easily suppress false disconnection detection. On the other hand, a disconnection detection threshold that is smaller than the vibration magnitude that can be measured when the optical fiber is broken (e.g., measured in a sensing invalid range) can more appropriately detect a disconnection. Therefore, by adopting a vibration magnitude that satisfies the upper and lower limits among multiple vibration magnitudes identified using index values, the range for determining the disconnection detection threshold can be clarified. This allows the disconnection detection threshold to be determined accurately.

[0047] Alternatively, the determiner 113 may identify a vibration range that is closer to the magnitude of vibration measured when the optical fiber is broken, among the vibration ranges identified when the index value is equal to or greater than the first value, and determine the magnitude of vibration included in the identified vibration range as the break detection threshold. When the optical fiber is broken, the optical signal is measured as if a large vibration has occurred, as described above. As described above, an index value that is equal to or greater than the first value can be said to have a relatively large vibration magnitude (signal strength) among the set of vibration ranges. Therefore, by identifying a vibration range that is identified by an index value that is equal to or greater than the first value and that is closer to the magnitude of vibration measured when the optical fiber is broken, the break detection threshold can be determined with high accuracy.

[0048] Furthermore, the determination unit 113 may calculate the degree of separation as an index value when a set of multiple vibration ranges is separated into two based on the classification result. For example, the determination unit 113 may calculate the degree of separation by applying Otsu's binarization method to the classification result. The degree of separation may be calculated, for example, as a ratio of the intra-group variance to the inter-group variance when the set of vibration ranges is divided into two groups (classes). Alternatively, the degree of separation may be calculated, for example, using the inter-group variance. Note that the method of calculating the degree of separation may also use, for example, cluster analysis. However, the method of calculating the degree of separation is not limited to these. By using the degree of separation as an index value, the disconnection detection threshold can be determined with even greater accuracy.

[0049] Furthermore, the determination unit 113 may determine the disconnection detection threshold by regarding the magnitude of vibration measured in the sensing invalid range of the optical fiber as the magnitude of vibration measured when the optical fiber is broken. This allows a value close to the magnitude of vibration of the optical signal that can be measured when the optical fiber is broken to be determined as the disconnection detection threshold, without actually disconnecting the optical fiber. Note that the sensing invalid range may be either or both of the sensing invalid range 31, which is the measurement result inside the sensing device 22, as shown in FIG. 6 above, or the sensing invalid range 32, which is the measurement result after the end of the optical fiber 21.

[0050] The detection unit 114 detects a break in the optical fiber using a break detection threshold based on the measurement results of the effective sensing range of the optical fiber. Furthermore, the detection unit 114 may detect a break in the optical fiber when the magnitude of vibration included in the measurement results exceeds the break detection threshold for a certain period of time. In other words, to detect a break in the optical fiber, the duration during which the measurement results exceed the break detection threshold may be used. This reduces false detections of breaks due to temporary disturbances (noise) such as gusts of wind. The duration may be set in advance in the information processing device 100 by an administrator or the like. Furthermore, when a break in the optical fiber is detected, the detection unit 114 may identify the position of the broken optical fiber based on the measurement point corresponding to the detected measurement results.

[0051] When the detection unit 114 detects a break in the optical fiber, the notification unit 115 notifies the terminal of the administrator or the like (for example, via the external system 24). Furthermore, the notification unit 115 may notify the terminal of the administrator or the like of the position of the optical fiber identified by the detection unit 114.

[0052] 9 is a flowchart showing the flow of the optical fiber sensing process. First, the information processing device 100 performs a process (S10) to determine the disconnection detection threshold for the optical fiber 21. The information processing device 100 may perform the disconnection detection threshold determination process when starting to use the sensing device 22, or when there is a change in the noise level due to a change in the environment around the optical fiber 21, and it becomes necessary to readjust the threshold.

[0053] FIG. 10 is a flowchart showing the flow of the disconnection detection threshold determination process. First, the acquisition unit 111 acquires the amplitude of vibration of the optical signal measured from multiple measurement points when the optical fiber 21 is in a stable state (S101). Specifically, when the optical fiber 21 is in a stable state, the sensing device 22 senses multiple measurement points on the optical fiber 21 and receives optical signals from each measurement point. The sensing device 22 then analyzes the amplitude of vibration and other information from each received optical signal and outputs the amplitude of vibration and other information to the information processing device 100. The acquisition unit 111 acquires measurement results, such as the amplitude of vibration of the optical signal measured from multiple measurement points on the optical fiber 21, from the sensing device 22. Alternatively, the acquisition unit 111 may acquire waveform data of the optical signal received from the sensing device 22 and analyze the waveform data to acquire the amplitude of vibration and other information at each measurement point. For example, the sensing device 22 or the acquisition unit 111 may receive the waveform data or measurement results of the optical signal at intervals of 10 seconds to 1 minute.

[0054] Then, the acquiring unit 111 determines whether or not the measurement results for the specified period have been acquired (S102). If the measurement results for the specified period have not been acquired, the acquiring unit 111 executes step S101 again.

[0055] If it is determined in step S102 that the measurement results for the specified period have been acquired, the classification unit 112 calculates the average value of the vibration magnitude for each measurement point (position of the optical fiber) of each optical signal (S103). Then, the classification unit 112 generates a histogram of vibration ranges from the average value (S104). That is, the classification unit 112 classifies the average value into one of the vibration ranges and generates a histogram in which the number of optical signals used to calculate the average value is used as the frequency. Alternatively, the classification unit 112 may classify the vibration magnitude of each optical signal into one of multiple vibration ranges each time, without calculating the average value, and add up the frequencies of optical signals classified for each vibration range. Furthermore, as described above, the vibration range may be the smallest unit of signal strength measurement. Therefore, the classification unit 112 may accumulate the frequencies of optical signals measured for each signal strength value. Then, the classification unit 112 may generate a histogram for each signal strength value.

[0056] Next, the determination unit 113 calculates the degree of separation for the histogram (S105). For example, the determination unit 113 may calculate the degree of separation by applying Otsu's binarization method to the histogram. Then, the determination unit 113 identifies the maximum vibration range among the vibration ranges when the degree of separation is equal to or greater than the first value (S106). Thereafter, the determination unit 113 determines the magnitude of vibration included in the identified vibration range as the disconnection detection threshold (S107).

[0057] Here, the determination unit 113 may derive a calculation formula for calculating an index value using the vibration range or the vibration magnitude as an input variable based on the histogram (classification result).The determination unit 113 may then determine the disconnection detection threshold (boundary value) based on the input variable when the decrease in the gradient of the calculation formula reaches a predetermined value in the direction in which the input variable increases from the maximum value of the index value calculated by the calculation formula.Alternatively, the determination unit 113 may identify an input variable that causes the index value calculated by the calculation formula to be equal to or greater than a first value and that is closest to the vibration magnitude measured when the optical fiber is disconnected (or in the sensing invalid range), and determine the vibration magnitude included in the vibration range corresponding to the identified input variable as the disconnection detection threshold.

[0058] FIG. 11 is a diagram illustrating the relationship between the histogram of vibration ranges and the degree of separation. The horizontal axis of the graph in FIG. 11 represents the amplitude of vibration of the optical signal. However, the horizontal axis of the graph in FIG. 11 may represent multiple vibration ranges obtained by grouping the ranges of vibration amplitude of the optical signal. Note that the numerical values ​​of the vibration amplitude are assumed to be tentative for the sake of simplicity. The same applies to the numerical values ​​in the following figures. The vertical axis on the left of the graph represents the frequency (frequency) of occurrence of values ​​in the histogram of vibration ranges. In other words, the left vertical axis represents the scale of the shaded bars for each vibration range. Therefore, the histogram (bar graph) as a classification result of the amplitude of vibration of the optical signal is represented by the horizontal axis and the left vertical axis. In this example, it can be seen from the histogram of the measurement results of the optical signal that it is roughly separated into two groups.

[0059] The right vertical axis of the graph in FIG. 11 represents the magnitude of the degree of separation 500. The degree of separation 500 is an example of the index value described above. The dashed line in the graph in FIG. 11 can be considered a two-dimensional representation of the relationship between the vibration range and the degree of separation derived from the histogram. Alternatively, the degree of separation 500 in FIG. 11 can be considered a two-dimensional representation of the "calculation formula (function) for calculating the index value (degree of separation 500)" described above. Therefore, the degree of separation 500 can be considered to be calculated by providing a predetermined vibration range (or vibration magnitude) as an input variable to the calculation formula. Conversely, the vibration range, etc., which is an input variable, can be considered to specify (multiple) vibration ranges (or vibration magnitudes) from the predetermined degree of separation in the calculation formula. For example, it can be seen that there are multiple vibration ranges (or vibration magnitudes) specified by the calculation formula when the degree of separation 500 reaches its maximum value in FIG. 11. Therefore, if the "first value" is set as the maximum value of the degree of separation 500, the determination unit 113 determines the maximum vibration range (specific value 51) among the vibration ranges when the degree of separation is maximum. Therefore, the determination unit 113 determines the magnitude of any vibration (signal strength) within the specified vibration range as the disconnection detection threshold. Note that the dashed line shown in the graph in FIG. 11 is merely an example. Therefore, the relationship between the vibration range derived from the histogram and the degree of separation may be represented by a curve. In this case, the determination unit 113 may determine the vibration range (corresponding to specific value 51) when the decrease in the gradient of the curve formed by connecting the degrees of separation calculated from the calculation formula reaches a predetermined value in the direction in which the input variable (vibration range) increases from the maximum value on the curve.

[0060] FIG. 12 is a diagram for explaining the effectiveness of the disconnection detection threshold. First, on the side of the histogram in FIG. 12 where the vibration range is small, there is a set of frequencies for normal operation 33. On the side of the histogram where the vibration range is large, there is a set of frequencies for the sensing invalid range 35. Note that the frequency for when a disturbance has occurred 34 is distributed near the center of the vibration range of the histogram. However, the frequency for when a disturbance has occurred 34 is significantly lower than the frequency for normal operation 33 and the frequency for when a disturbance has occurred 34.

[0061] Here, to separate the two peaks (normal state 33 and sensing invalid range 35), the median value 50 is selected from the maximum values ​​of the separation degree 500 in FIG. 12 , and the disconnection detection threshold determined from the vibration range 501 identified from the median value 50 is mathematically the most effective value. In contrast, in the technology disclosed herein, the disconnection detection threshold is determined using the largest value (the rightmost value) from among the multiple vibration ranges identified from the maximum value of the separation degree 500. This is because the optical signal (reflected light) measured from the optical fiber 21 may generate constantly large noise due to unknown disturbances that cannot be observed during measurement when the disconnection detection threshold is initially set (determined). For example, even if the wind near the optical fiber 21 was calm at the time of measurement to determine the disconnection detection threshold, there is a possibility that constantly large signals may continue to be observed during optical fiber sensing operation due to the influence of a typhoon or the like. Therefore, the information processing device 100 according to the present disclosure does not use a threshold based on the mathematically most effective degree of separation (vibration range 501 identified from median 50) as the disconnection detection threshold, but identifies a vibration range 511 that is closest to the magnitude of vibration measured when the optical fiber is disconnected, from among the vibration ranges identified when separation 500 is equal to or greater than a first value, and determines the magnitude of vibration included in the identified vibration range 511 as the disconnection detection threshold. This makes it possible to exclude cases where a temporarily large signal is generated by noise caused by unknown disturbances, etc., and reduce false detection of a disconnection.

[0062] After step S107 in Fig. 10, that is, after the disconnection detection threshold determination process in step S10 in Fig. 9, the information processing device 100 performs a sensing range setting process (S20 in Fig. 9). The information processing device 100 performs the sensing range setting process when starting to use the sensing device 22. Note that if the information processing device 100 performs the sensing range setting process once for a specific optical fiber 21 and then executes the disconnection detection threshold determination process in step S10 again, the re-execution of the sensing range setting process may be omitted.

[0063] Specifically, the information processing device 100 first performs an optical fiber end detection process. That is, the information processing device 100 excludes data corresponding to measurement points inside the sensing device 22 from the multiple measurement results acquired in step S101. That is, the information processing device 100 excludes from the measurement results portions with higher vibration amplitudes from the sensing source to a predetermined range. The information processing device 100 then identifies the first measurement point from the excluded measurement results where the vibration amplitude exceeds the breakage detection threshold. The information processing device 100 then detects the identified measurement point as the end of the optical fiber 21. The information processing device 100 then sets the range inside the sensing device 22 and the area after the fiber end as a sensing invalid range among the multiple measurement points, and sets the measurement points sandwiched between the two sensing invalid ranges as a sensing valid range.

[0064] Thereafter, the information processing device 100 performs the abnormality detection process (S30 in FIG. 9). The information processing device 100 continues to perform the abnormality detection process while the intrusion detection by the optical fiber 21 is being performed.

[0065] FIG. 13 is a flowchart showing the flow of the anomaly detection process. FIG. 14 is a diagram showing an example of changes in each element of the anomaly record array. The anomaly record array is an array that records the number of times a threshold is exceeded for each position of the optical fiber (measurement point in the effective sensing range). For example, anomaly record array 61 is in its initial state, which is the start of the anomaly detection process, and the value of each element of the array (e.g., elements 612 and 614) is set to "0." The flow of FIG. 13 will be explained below, with reference to FIG. 14 as appropriate.

[0066] First, the acquisition unit 111 acquires the amplitude of vibration of the optical signal measured from each measurement point within the effective sensing range of the optical fiber (S301). Then, the detection unit 114 determines whether the acquired amplitude of vibration exceeds the disconnection detection threshold (S302). If the amplitude of vibration exceeds the disconnection detection threshold, the detection unit 114 adds 2 to the value of the element in the abnormality record array corresponding to the measurement point of the optical signal (S303). For example, if the amplitude of vibration at the measurement points corresponding to elements 622 and 624 in the abnormality record array 62 in FIG. 14 exceeds the disconnection detection threshold, the detection unit 114 adds 2 to the values ​​of elements 622 and 624, respectively.

[0067] After step S303, or if it is determined in step S302 that the magnitude of vibration does not exceed the disconnection detection threshold, the detection unit 114 subtracts 1 from the values ​​of all elements of the abnormality record array whose element value is 1 or greater (S304). For example, the detection unit 114 subtracts "1" from the values ​​of elements 622 and 624 of the abnormality record array 62 in Fig. 14. As a result, the values ​​of elements 632 and 634 of the abnormality record array 63 become "1."

[0068] The detection unit 114 then waits for a certain period of time (S305). The certain period of time may be, for example, 100 milliseconds. However, the certain period of time is not limited to this. The detection unit 114 then determines whether or not an element value that exceeds the abnormality continuation threshold exists in the abnormality record array (S306). Here, the "abnormality continuation threshold" refers to the threshold value of the element value when the magnitude of vibration measured at a specific measurement point continues to exceed the disconnection detection threshold. If it is determined in step S306 that no element value exceeds the abnormality continuation threshold exists, the acquisition unit 111 executes step S301 again. The detection unit 114 then executes steps S302 to S306.

[0069] For example, assume that the magnitude of vibration at the measurement point corresponding to element 632 does not exceed the disconnection detection threshold, but the magnitude of vibration at the measurement point corresponding to element 634 exceeds the disconnection detection threshold. In this case, in step S303, the detection unit 114 adds "2" to the value of element 634. Therefore, for example, the value of element 642 in the abnormality record array 64 remains "1" and the value of element 644 becomes "3." Then, in step S304, the detection unit 114 subtracts "1" from the values ​​of elements 642 and 644. Therefore, for example, the value of element 652 in the abnormality record array 65 becomes "0" and the value of element 654 becomes "2." In this way, if the magnitude of vibration continues to exceed the disconnection detection threshold at the measurement point corresponding to the fourth element (614 to 654) in the abnormality record array, the value of the fourth element gradually increases. On the other hand, if the magnitude of the vibration at the measurement point corresponding to the second element (612 to 652) of the abnormality recording array temporarily exceeds the open circuit detection threshold and then no longer exceeds the open circuit detection threshold, the value of the second element gradually decreases to "0".

[0070] On the other hand, if it is determined in step S306 that an element value exceeding the abnormality duration threshold exists, the detection unit 114 identifies the position (measurement point) of the optical fiber corresponding to the element exceeding the abnormality duration threshold (S307). For example, if the abnormality duration threshold is "99," the value of element 6n4 in the abnormality record array 6n (n is a natural number greater than or equal to 6) in FIG. 14 is "100," so the detection unit 114 determines that an element value exceeding the abnormality duration threshold exists. The detection unit 114 then identifies the measurement point corresponding to the fourth element in the abnormality record array as the location (failure location) of the optical fiber break. The notification unit 115 then notifies the identified location as the location of the optical fiber break (S308). Specifically, the notification unit 115 transmits information about the location of the optical fiber break to the administrator's terminal or the like via the network N and the external system 24.

[0071] FIG. 15 is a diagram showing an example of the position of the optical fiber and the magnitude of vibration when a break is detected. The horizontal axis of the graph in FIG. 15 represents the distance from the optical signal source. The vertical axis of the graph represents the signal strength (vibration magnitude) of the measured optical signal. In this graph, the break detection threshold 76 is set at a signal strength of approximately 60. The signal strengths measured in areas 71 and 72 exceed the break detection threshold 76 but are within the sensing invalid range. Therefore, the signals in areas 71 and 72 are not detected as abnormal. Furthermore, signal strength 73 is assumed to be due to disturbance noise. Disturbance noise can occur temporarily due to the influence of, for example, a typhoon. However, in the case of disturbance noise, if the optical fiber 21 is not broken, the signal strength will not exceed the break detection threshold 76, or even if it does exceed it temporarily, it will not continue for a certain period of time (based on the abnormality duration threshold). Furthermore, signal strength 74 is assumed to be due to noise during normal operation. Therefore, when the measured optical signals have signal intensities 73 and 74, these signals are not detected as abnormal because they are equal to or less than the disconnection detection threshold 76. On the other hand, the signal intensity of signal 75 exceeds the disconnection detection threshold 76. Therefore, if the signal intensity of signal 75 continues for a certain period of time (based on the abnormality continuation threshold), signal 75 is determined to be a reflected optical signal due to a disconnection in the optical fiber 21, and is detected as abnormal.

[0072] FIG. 16 is a diagram illustrating the relationship between the magnitude of vibration and the situation at the time of measurement. The vertical axis represents the magnitude of vibration of the measured reflected light. For example, the magnitude of vibration of the normal noise floor is often around 5, and the magnitude of vibration due to disturbance noise is often around 20. On the other hand, the median value of the magnitude of vibration when a break in the optical fiber is detected is, for example, around 80. With the technology disclosed herein, the break detection threshold can be determined to, for example, around 60. This makes it possible to prevent disturbance noise from being mistakenly detected as a break. On the other hand, it is possible to properly detect actual breaks in the optical fiber.

[0073] As described above, the technology disclosed herein enables accurate determination of the disconnection detection threshold. Furthermore, by defining the interior of the sensing device 22 and the area beyond the end of the optical fiber as a sensing invalid range, the effective sensing range can be appropriately narrowed. Therefore, a disconnection detection threshold that can further reduce false positives can be accurately determined. Furthermore, because the disconnection detection threshold can be accurately determined, a user, such as an administrator, can detect an optical fiber disconnection simply by setting the duration until the optical fiber is determined to have been disconnected (a certain period of time based on the abnormality duration threshold). Therefore, when installing an optical fiber sensing system, the labor required for tuning the disconnection detection threshold, etc., can be reduced. Furthermore, the technology disclosed herein uses statistical techniques to determine a disconnection detection threshold that is less likely to cause false positives and has high detection accuracy. In addition, this embodiment can achieve the same effects as those of the first and second embodiments described above.

[0074] In this fourth embodiment, a case will be described in which the disconnection detection threshold is determined by obtaining two or more measurement results (signal strength) at least at one measurement point (within the effective sensing range) of the optical fiber, one at the time of connection and one at the time of disconnection. For example, when the optical fiber is about 100 m long, there may be one measurement point, which is useful.

[0075] The acquisition unit 111 according to the fourth embodiment acquires the amplitude of vibration of each optical signal by combining one or more optical signals measured from a predetermined measurement point on the optical fiber and one or more optical signals measured when the optical fiber is broken. For example, the optical fiber may be measured at one measurement point, and measurements may be taken multiple times in a stable state for a certain period of time (e.g., 30 minutes), and then the optical fiber may be intentionally broken and measurements may be taken after the break. Note that other configurations according to the fourth embodiment are the same as those of the third embodiment described above, and therefore redundant explanations and illustrations will be omitted as appropriate. The following description will focus on the differences from the third embodiment.

[0076] 17 is a flowchart showing the flow of the disconnection detection threshold determination process. First, the acquisition unit 111 acquires the amplitude of vibration of the optical signal measured from one measurement point when the optical fiber is in a stable state (S401). Then, the acquisition unit 111 determines whether the designated number of measurement results have been acquired (S402). If the designated number of measurement results have not been acquired, the acquisition unit 111 executes step S401 again.

[0077] If it is determined in step S402 that the designated number of measurement results have been acquired, the person who set the disconnection detection threshold (such as an administrator) disconnects the measurement point of the optical fiber (S403). Thereafter, the acquisition unit 111 acquires the amplitude of vibration of the optical signal measured from the optical fiber after the disconnection (S404). Note that step S404 may be executed multiple times.

[0078] The classification unit 112 generates a histogram of the vibration range from the magnitude of vibration of each optical signal (S405). After that, the information processing device 100 executes the processes of steps S105 to S107 in FIG.

[0079] In this way, in the fourth embodiment, if there is at least one measurement point on the optical fiber within the effective sensing range, the disconnection detection threshold can be determined with high accuracy by obtaining two or more measurement results (signal strength) at the time of connection and at the time of disconnection. In addition, the present embodiment can achieve various effects similar to those of the first, second, and third embodiments described above.

[0080] 18 is a block diagram showing the hardware configuration of the above-described information processing device 100, etc. The information processing device 100 includes a memory 101, a processor 102, and a network interface 103.

[0081] The memory 101 is configured by a combination of volatile memory and non-volatile memory. The volatile memory is, for example, a volatile storage device such as RAM (Random Access Memory), and is a storage area for temporarily storing information while the processor 102 is operating. The non-volatile memory is, for example, a non-volatile storage device such as a hard disk or flash memory. The memory 101 stores at least a computer program that implements the processing of the information processing method (object-oriented software development support method) in the information processing device 100 according to the present disclosure. Note that the memory 101 may include storage located remotely from the processor 102. In this case, the processor 102 may access the memory 101 via an I / O (Input / Output) interface (not shown).

[0082] The processor 102 is a control device that controls each component of the information processing device 100. The processor 102 reads and executes software (computer programs) from the memory 101. As a result, the processor 102 realizes the functions of the acquisition unit 111, the classification unit 112, the determination unit 113, the detection unit 114, and the notification unit 115. In other words, the processor 102 performs the optical fiber sensing process of the information processing method in the information processing device 100 according to the present disclosure. The processor 102 may be, for example, a microprocessor, an MPU (Multi Processing Unit), or a CPU (Central Processing Unit). The processor 102 may also include multiple processors.

[0083] The network interface 103 may be used to communicate with network nodes. The network interface 103 may include, for example, a network interface card (NIC) conforming to the IEEE 802.3 series. IEEE stands for Institute of Electrical and Electronics Engineers. The network interface 103 may also include a wireless local area network (LAN), a wired LAN, Wi-Fi (registered trademark), Bluetooth (registered trademark), etc.

[0084] 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. Furthermore, each embodiment can be combined with other embodiments as appropriate.

[0085] Each drawing is merely an example for describing one or more embodiments. Each drawing may not relate to only one particular embodiment, but may also relate to one or more other embodiments. As will be understood by those skilled in the art, various features or steps described with reference to any one drawing can be combined with features or steps shown in one or more other drawings to create, for example, an embodiment not explicitly shown or described. Not all features or steps shown in any one drawing are necessary to describe an exemplary embodiment, and some features or steps may be omitted. The order of steps described in any drawing may be changed as appropriate.

[0086] The program includes instructions (or software code) that, when loaded into a computer, cause the computer to perform one or more functions described in the embodiments. The program may be stored on a non-transitory computer-readable medium or a tangible storage medium. By way of example and not limitation, computer-readable media or tangible storage media include random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD) or other memory technologies, CD-ROM, digital versatile disc (DVD), Blu-ray disc or other optical disk storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage devices. The program 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.

[0087] Some or all of the above embodiments can be described as, but are not limited to, the following supplementary notes. (Supplementary Note 1) An information processing device comprising: an acquisition means for acquiring a vibration magnitude of an optical signal measured from an optical fiber; a classification means for classifying the optical signals by the vibration magnitude; and a determination means for determining a disconnection detection threshold for detecting a disconnection of the optical fiber based on the classification results. (Supplementary Note 2) The information processing device according to Supplementary Note 1, wherein the determination means calculates an index value from the classification results and determines the disconnection detection threshold based on the index value. (Supplementary Note 3) The information processing device according to Supplementary Note 2, wherein the determination means determines, as the disconnection detection threshold, a vibration magnitude corresponding to the index value that is equal to or greater than a first value. (Supplementary Note 4) The information processing device according to Supplementary Note 3, wherein the determination means determines, as the disconnection detection threshold, the largest vibration magnitude among a plurality of vibration magnitudes corresponding to the index values ​​that are equal to or greater than the first value. (Supplementary Note 5) The information processing device according to Supplementary Note 2 or 3, wherein the index value is a value that increases as the degree of overlap between two sets of vibration magnitudes in the classification result decreases when the sets are separated into two sets. (Supplementary Note 6) The information processing device according to Supplementary Note 1 or 2, wherein the classification result includes the vibration magnitude of the optical signal measured in a sensing invalid range of the optical fiber. (Supplementary Note 7) The information processing device according to Supplementary Note 1 or 2, wherein the acquisition means acquires vibration magnitudes of a plurality of optical signals measured from each of a plurality of measurement points on the optical fiber, and the classifying means classifies each of the plurality of optical signals into one of a plurality of vibration ranges based on the vibration magnitude. (Supplementary Note 8) The information processing device according to Supplementary Note 1 or 2, wherein the acquisition means acquires the vibration magnitudes of each optical signal, using one or more optical signals measured from predetermined measurement points on the optical fiber and one or more optical signals measured when the optical fiber is broken, as a plurality of optical signals, and the classifying means classifies each of the plurality of optical signals into one of a plurality of vibration ranges based on the vibration magnitude.(Supplementary Note 9) An information processing method in which a computer acquires the amplitudes of vibration of optical signals measured from an optical fiber, classifies the optical signals by the amplitude of vibration, and determines a break detection threshold for detecting a break in the optical fiber based on the classification results. (Supplementary Note 10) An information processing program that causes a computer to execute the following steps: an acquisition process for acquiring the amplitudes of vibration of optical signals measured from an optical fiber, a classification process for classifying the optical signals by the amplitude of vibration, and a determination process for determining a break detection threshold for detecting a break in the optical fiber based on the classification results. (Supplementary Note A1) An information processing device comprising: an acquisition means for acquiring amplitudes of vibration of a plurality of optical signals measured from an optical fiber, a classification means for classifying each piece of information about the plurality of optical signals into one of a plurality of vibration ranges based on the amplitude of vibration, and a determination means for determining a break detection threshold for detecting a break in the optical fiber based on the classification results. (Supplementary Note A2) The information processing device according to Supplementary Note A1, wherein the determination means calculates an index value indicating a degree of separation when the plurality of vibration ranges are separated into two sets from the classification result, and determines the disconnection detection threshold based on the index value. (Supplementary Note A3) The information processing device according to Supplementary Note A2, wherein the determination means determines, as the disconnection detection threshold, a magnitude of vibration included in the vibration range corresponding to the index value equal to or greater than a first value. (Supplementary Note A4) The information processing device according to Supplementary Note A3, wherein the determination means determines, as the disconnection detection threshold, a magnitude of vibration that is greater than a median of the plurality of vibration magnitudes corresponding to the index value equal to or greater than the first value and is smaller than a magnitude of vibration that can be measured when the optical fiber is disconnected. (Supplementary Note A5) The information processing device according to Supplementary Note A4, wherein the determination means determines the disconnection detection threshold by regarding the magnitude of vibration measured in a sensing invalid range of the optical fiber as a magnitude of vibration that can be measured when the optical fiber is disconnected.(Appendix A6) The information processing device according to any one of Appendices A2 to A5, wherein the index value is a value that increases as the degree of overlap between the sets when the plurality of vibration ranges are separated into two sets decreases. (Appendix A7) The information processing device according to any one of Appendices A1 to A6, wherein the acquisition means acquires amplitudes of vibration of the plurality of optical signals measured from each of a plurality of measurement points on the optical fiber. (Appendix A8) The information processing device according to any one of Appendices A1 to A6, wherein the acquisition means acquires amplitudes of vibration of each optical signal, using one or more optical signals measured from predetermined measurement points on the optical fiber and one or more optical signals measured when the optical fiber is broken. (Appendix B1) An information processing method, wherein a computer acquires amplitudes of vibration of the plurality of optical signals measured from an optical fiber, classifies each piece of information about the plurality of optical signals into one of a plurality of vibration ranges based on the amplitude of vibration, and determines a break detection threshold for detecting a break in the optical fiber based on the classification result. (Appendix C1) An information processing program that causes a computer to execute the following steps: an acquisition process that acquires the vibration magnitudes of multiple optical signals measured from an optical fiber; a classification process that classifies each piece of information about the multiple optical signals into one of multiple vibration ranges based on the vibration magnitudes; and a determination process that determines a break detection threshold for detecting a break in the optical fiber based on the classification results.

[0088] Some or all of the elements (e.g., configurations and functions) described in Appendix 2 to Appendix 8 that are dependent on Appendix 1 (e.g., device) may also be dependent on Appendix 9 (e.g., method) and Appendix 10 (e.g., program) in the same dependency relationship as Appendix 2 to Appendix 8. Some or all of the elements (e.g., configurations and functions) described in Appendix A2 to Appendix A8 that are dependent on Appendix A1 (e.g., device) may also be dependent on Appendix B1 (e.g., method) and Appendix C1 (e.g., program) in the same dependency relationship as Appendix A2 to Appendix A8. Some or all of the elements described in any appendix may be applicable to various hardware, software, recording means for recording software, systems, and methods.

[0089] Although the present invention has been described above with reference to the embodiments, the present invention is not limited to the above. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the invention.

[0090] This application claims priority based on Japanese Patent Application No. 2024-085661, filed May 27, 2024, the disclosure of which is incorporated herein in its entirety by reference.

[0091] 1, 1a, 100 Information processing device, 11, 11a, 111 Acquisition unit, 12, 12a, 112 Classification unit, 13, 13a, 113 Determination unit, 114 Detection unit, 115 Notification unit, 1000 Optical fiber sensing system, N Network, U Person, 21 Optical fiber, 22 Sensing device, 23 Camera, 24 External system, 30 Sensing effective range, 31, 32, 35 Sensing invalid range, 41 Measurement value when vibration occurs, 42 Measurement value when disconnection occurs, 500 Separation degree, 50 Median value, 51 Specific value, 33 Normal state, 34 When disturbance occurs, 501, 511 Vibration range, 61, 62, 63, 64, 6, 6n Abnormal record array, 612, 614, 622, 624, 632, 634, 642, 644, 652, 654, 6n4 elements, 71, 72 areas, 73, 74 signal strength, 75 signals, 76 disconnection detection threshold, 101 memory, 102 processor, 103 network interface

Claims

1. An information processing device comprising: an acquisition means for acquiring the magnitude of vibration of an optical signal measured from an optical fiber; a classification means for classifying the optical signals according to the magnitude of the vibration; and a determination means for determining a break detection threshold for detecting a break in the optical fiber based on the classification results.

2. The information processing device according to claim 1, wherein the determining means calculates an index value from the classification result and determines the disconnection detection threshold based on the index value.

3. The information processing device according to claim 2, wherein the determining means determines the magnitude of vibration corresponding to the index value equal to or greater than a first value as the disconnection detection threshold.

4. The information processing device according to claim 3, wherein the determining means determines the largest vibration magnitude among a plurality of vibration magnitudes corresponding to the index value that is equal to or greater than the first value as the disconnection detection threshold.

5. The information processing device according to claim 2 or 3, wherein the index value is a value that increases as the degree of overlap between the two sets when the set of vibration magnitudes in the classification result is separated into two sets decreases.

6. The information processing device according to claim 1 or 2, wherein the classification result includes the magnitude of vibration of the optical signal measured in the sensing invalid range of the optical fiber.

7. An information processing device according to claim 1 or 2, wherein the acquisition means acquires the amplitudes of vibration of a plurality of optical signals measured from each of a plurality of measurement points on the optical fiber, and the classification means classifies each of the plurality of optical signals into one of a plurality of vibration ranges based on the amplitude of the vibration.

8. The information processing device according to claim 1 or 2, wherein the acquisition means acquires the magnitude of vibration of each optical signal by treating one or more optical signals measured from a predetermined measurement point on the optical fiber and one or more optical signals measured when the optical fiber is broken as a plurality of optical signals, and the classification means classifies each of the plurality of optical signals into one of a plurality of vibration ranges based on the magnitude of the vibration.

9. An information processing method in which a computer acquires the amplitude of vibration of an optical signal measured from an optical fiber, classifies the optical signals according to the amplitude of the vibration, and determines a break detection threshold for detecting a break in the optical fiber based on the classification results.

10. An information processing program that causes a computer to execute the following steps: an acquisition process for acquiring the magnitude of vibration of an optical signal measured from an optical fiber; a classification process for classifying the optical signals according to the magnitude of the vibration; and a determination process for determining a break detection threshold for detecting a break in the optical fiber based on the classification results.

11. An information processing device comprising: an acquisition means for acquiring the amplitude of vibration of a plurality of optical signals measured from an optical fiber; a classification means for classifying each piece of information relating to the plurality of optical signals into one of a plurality of vibration ranges based on the amplitude of the vibration; and a determination means for determining a break detection threshold for detecting a break in the optical fiber based on the classification result.

12. The information processing device according to claim 11, wherein the determination means calculates an index value indicating the degree of separation when the plurality of vibration ranges are separated into two sets from the classification result, and determines the disconnection detection threshold based on the index value.

13. The information processing device according to claim 12, wherein the determining means determines the magnitude of vibration included in the vibration range corresponding to the index value that is equal to or greater than a first value as the disconnection detection threshold.

14. The information processing device described in claim 13, wherein the determination means determines, as the break detection threshold, a vibration magnitude that is greater than the median of multiple vibration magnitudes corresponding to the index value that is equal to or greater than the first value and is smaller than the vibration magnitude that can be measured when the optical fiber is broken.

15. An information processing device as described in claim 14, wherein the determination means determines the break detection threshold by regarding the magnitude of the vibration measured in the sensing ineffective range of the optical fiber as the magnitude of vibration that can be measured when the optical fiber is broken.

16. An information processing device according to any one of claims 12 to 15, wherein the index value is a value that increases as the degree of overlap between the sets when the multiple vibration ranges are separated into two sets decreases.

17. An information processing device according to any one of claims 11 to 16, wherein the acquisition means acquires the amplitudes of vibration of the plurality of optical signals measured from each of a plurality of measurement points on the optical fiber.

18. An information processing device according to any one of claims 11 to 16, wherein the acquisition means acquires the amplitude of vibration of each optical signal, using one or more optical signals measured from a predetermined measurement point on the optical fiber and one or more optical signals measured when the optical fiber is broken as the multiple optical signals.

19. An information processing method in which a computer acquires the amplitudes of vibrations of multiple optical signals measured from an optical fiber, classifies each piece of information about the multiple optical signals into one of multiple vibration ranges based on the amplitude of the vibrations, and determines a break detection threshold for detecting a break in the optical fiber based on the classification results.

20. An information processing program that causes a computer to execute the following steps: an acquisition process that acquires the vibration magnitudes of multiple optical signals measured from an optical fiber; a classification process that classifies each piece of information about the multiple optical signals into one of multiple vibration ranges based on the vibration magnitudes; and a determination process that determines a break detection threshold for detecting a break in the optical fiber based on the classification results.

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