Vibration analysis processing device

Abstract

The purpose of the present invention is to provide a vibration analysis processing device that is capable of identifying an event occurrence location without being affected by an installation environment of an optical fiber.　A vibration analysis processing device 10 is characterized by using a vibration measuring instrument 20 and an optical fiber cable 50 laid along a route to be detected to measure in advance a point where "a unique frequency peak occurring in a normal state" is observed and a band where the unique frequency peak is observed and hold the point and the band as reference data in the normal state, and to detect that vibration data measured in a monitoring state includes "vibration having the unique frequency peak", which is not recorded in the reference data in the normal state, and the position of the vibration, thereby estimating the occurrence location of an event accompanied by new unique vibration such as construction occurrence.

Description

Vibration analysis processing device

[0001] The present disclosure relates to a vibration analysis processing device for analyzing vibration data of an optical fiber cable.

[0002] Research is underway on a technique for acquiring vibrations transmitted through an optical fiber using DAS (Distributed Acoustic Sensing) technology and detecting an event that generates the vibration (see, for example, Non-Patent Document 1). There is also a technique for monitoring vibrations using an optical fiber and DAS and detecting a location where an event has occurred by capturing specific vibration characteristics (see, for example, Non-Patent Document 2).

[0003] Lasertec Corporation Technical Information "Optical Fiber Distributed Vibration Sensor (DAS)", https: / / lazoc.jp / technical / das / (searched on October 25, 2*4) Femi Tanimola et.al. "Distributed fibre optic sensors for pipeline protection", Journal of Natural Gas Science and Engineering * (2009), P134-143

[0004] The vibration data of the optical fiber by DAS changes in the characteristics of ambient noise and the acquired vibration depending on the installation environment of the optical fiber. Since the disclosed vibration analysis does not consider the characteristic change due to the installation environment, there is a problem that it is difficult to reduce the change in the event detection rate due to the change in the installation environment of the optical fiber.

[0005] Therefore, an object of the present invention is to provide a vibration analysis processing device that can specify the location where an event occurs without being affected by the installation environment of the optical fiber in order to solve the above problems.

[0006] To achieve the above objectives, the vibration analysis processing device according to the present invention performs the following actions: generating a series of flags indicating the presence or absence of singular vibrations and a series of coefficients indicating the presence or absence of singular vibrations (determination values) from vibration data obtained by DAS and normalizing them; acquiring reference data in advance; comparing the vibration data at the time of monitoring with the reference data to determine whether or not vibrations not recorded in the vibration data at the time of monitoring are included; and detecting the location of those vibrations.

[0007] Specifically, the vibration analysis processing apparatus according to the present invention comprises an input unit into which vibration data transmitted to an optical fiber cable measured by a vibration measuring instrument is input, and a calculation processing unit that performs a preparation step and a monitoring step, wherein the calculation processing unit, in the preparation step, divides the vibration data into a plurality of sections in the distance direction of the optical fiber cable, generates a unit flag sequence for each section and per unit time, assigning a flag to each of the vibration data in each section to indicate whether or not vibration is occurring for each bandwidth, and generates a reference flag sequence for each section by calculating the logical OR in the time direction for each bandwidth of the unit flag sequence, and in the monitoring step, generates the unit flag sequence for each section and per unit time, compares the unit flag sequence with the reference flag sequence for the section corresponding to the unit flag sequence, and generates a modified flag sequence in which frequency components for which both have the same flag are flags to indicate that vibration is not occurring, The method is characterized by: generating a bit sequence that represents, in bits, the intervals in which the correction flag sequence, arranged in the time direction, contains a flag indicating that the oscillation occurs in any of the bands, at a predetermined rate or higher, and other intervals; generating a judgment value sequence by arranging moving average values ​​calculated with an arbitrary window size in the distance direction for the bit sequence, in the distance direction; and detecting a point or range in the judgment value sequence where the moving average value exceeds an arbitrary threshold.

[0008] By standardizing the vibration data of optical fibers, the influence of the optical fiber installation environment can be reduced. Furthermore, by comparing it with reference data, it is possible to estimate the location of new events, such as construction work. Therefore, the present invention can provide a vibration analysis processing device that can identify the location of events without being affected by the optical fiber installation environment.

[0009] Furthermore, "dividing the optical fiber cable into multiple sections in the distance direction" means the following: Due to the principles of DAS, vibrations are measured discretely along the length of the optical fiber. Therefore, a "section" is either "a section divided for each discretely occurring vibration" or "a section divided into multiple discrete vibrations". In the latter case, the number of vibrations to be grouped is at the user's discretion, and the multiple vibrations included in each section are treated as a single data point to determine whether or not a singular vibration is occurring.

[0010] Here, the arithmetic processing unit is characterized by generating the unit flag sequence by performing a flag assignment operation for each section, the flag assignment operation is characterized by obtaining the frequency spectrum of time-series data of the vibration data at an arbitrary time, calculating the average intensity of the frequency spectrum for each band, and assigning a flag indicating "vibration present" to the band whose ratio of the average intensity with the adjacent band is greater than a predetermined value at the arbitrary time, and assigning a flag indicating "no vibration" to the other bands.

[0011] The vibration analysis processing device according to the present invention may further include an output unit that outputs the location or range as the vibration generation location of the optical fiber cable.

[0012] The vibration analysis processing apparatus according to the present invention may further include: an identification unit that compares information on the route along which the optical fiber cable is laid with the distance of the point or range in the longitudinal direction of the optical fiber cable from the vibration measuring instrument to identify the geographical location of the point or range; and an output unit that outputs the geographical location.

[0013] The present invention is a program for causing a computer to function as the vibration analysis processing device described above. The vibration analysis processing device of the present invention can also be realized by a computer and a program, and the program can be recorded on a recording medium or provided via a network.

[0014] Furthermore, the above inventions can be combined as much as possible.

[0015] The present invention provides a vibration analysis processing device that can identify the location of an event without being affected by the installation environment of the optical fiber.

[0016] This is a diagram illustrating a system for identifying the location of unusual vibrations equipped with a vibration analysis processing device according to the present invention. This is a diagram illustrating the vibration analysis processing device according to the present invention. This is a flowchart illustrating the basic operation performed by the vibration analysis processing device according to the present invention. This is time-series data from 0 to 1 second from the start of measurement at a point located at a longitudinal distance X [m] from the vibration measuring instrument 20 to the optical fiber cable 50. This is a frequency spectrum obtained by frequency analysis of vibration data (time-series data) every second. This is a table listing the average values ​​of the frequency spectrum intensity for each band. This is a diagram illustrating the process of detecting unusual vibration suspect flags for each band (unit flag series creation process). This is a diagram illustrating the unusual vibration suspect series at an arbitrary time at an arbitrary point. This is a table listing the unusual vibration suspect series at an arbitrary point in order of measurement time. This is a diagram illustrating the method for determining the unusual vibration section. This is a flowchart illustrating the vibration location estimation method performed by the vibration analysis processing device according to the present invention. This is a table listing the average values ​​of the frequency spectrum intensity for each band. This is a diagram illustrating the process of detecting unusual vibration suspect flags for each band (unit flag series creation process). This is a diagram illustrating the process of obtaining a reference flag series. This is a diagram illustrating the process of obtaining a reference flag series over the entire length of the optical fiber cable. This is a table listing the average values ​​of frequency spectral intensity for each frequency band. This is a diagram illustrating the process of detecting suspected anomalous vibration flags for each frequency band (unit flag sequence creation process). This is a diagram illustrating the process of obtaining a modified suspected anomalous vibration flag sequence (modified unit flag sequence) based on the reference flag sequence. This is a diagram illustrating the suspected anomalous vibration sequence at an arbitrary point and time. This is a table listing the suspected anomalous vibration sequences at an arbitrary point in order of measurement time. This is a diagram illustrating the method for determining the anomalous vibration interval.

[0017] Embodiments of the present invention will be described with reference to the attached drawings. The embodiments described below are examples of the present invention, and the present invention is not limited to these embodiments. In this specification and in the drawings, components with the same reference numerals refer to the same components.

[0018] (Basic Operation) Figure 1 is a diagram illustrating a system for identifying the location of a unique vibration, which includes the vibration analysis processing device 10 of this embodiment. The system for identifying the location of a unique vibration according to the present invention comprises an optical fiber cable 50, a vibration measuring instrument 20, and a vibration analysis processing device 10. The basic operation of the vibration analysis processing device 10 will be explained using Figure 1.

[0019] The optical fiber cable 50 is installed above, on the surface of, or underground of the road 40 to be subjected to vibrations. The vibration measuring instrument 20 measures the vibrations received by the optical fiber cable 50 as a distribution along the longitudinal direction of the optical fiber cable 50, for example, using DAS. The vibration analysis processing device 10 detects the location along the longitudinal direction of the optical fiber where vibrations of a specific frequency component are particularly large, based on the vibration distribution measured by the vibration measuring instrument 20, as a unique vibration generation point. The vibration analysis processing device 10 then estimates the vicinity of the unique vibration generation point on the road 40 based on the positional relationship between the longitudinal position of the optical fiber cable 50 and the road 40. A map may be displayed on the monitor 15, and the unique vibration generation point may be displayed on the map.

[0020] The vibration analysis processing device 10 will be described in more detail. Figure 2 is a diagram illustrating the vibration analysis processing device 10. The vibration analysis processing device 10 includes an input unit 11 into which vibration data transmitted to the optical fiber cable 50 measured by the vibration measuring instrument 20 is input, and an arithmetic processing unit 12 which divides the optical fiber cable 50 into a plurality of sections in the distance direction and generates a bit sequence that assigns bits to each of the sections based on the vibration data to indicate whether or not singular vibrations of singular frequency components are occurring (Figure 9(C), Figure 10(A)), generates a judgment value sequence by arranging moving average values ​​calculated with an arbitrary window size in the distance direction for the bit sequence in the distance direction, and detects a point or range in the judgment value sequence where the moving average value exceeds an arbitrary threshold.

[0021] Here, the arithmetic processing unit 12 is characterized by generating the bit sequence by performing a bit assignment operation for each section, and the bit assignment operation is characterized by obtaining the frequency spectrum of time-series data of arbitrary time from the vibration data (Figure 5), calculating the average intensity of the frequency spectrum for each predetermined band (Figure 6), determining whether there is a specific band at the arbitrary time in which the ratio of the average intensity of adjacent bands is greater than a predetermined value (Figure 7), and assigning a flag indicating that the singular vibration is "present" (e.g., "1") to the section if the specific band exists at a predetermined or higher rate in a plurality of consecutive arbitrary time periods, and assigning a flag indicating that the singular vibration is "absent" (e.g., "0") to the section in other cases (Figure 9 left).

[0022] The output unit 14 outputs the aforementioned location or area as the vibration generation point of the optical fiber cable 50. Alternatively, if the vibration analysis processing device 10 includes a identification unit 13 that compares information on the route along which the optical fiber cable 50 is laid with the distance of the aforementioned location or area from the vibration measuring instrument 20 in the longitudinal direction of the optical fiber cable 50 to identify the geographic location of the aforementioned location or area, the output unit 14 outputs the geographic location. The information output by the output unit 14 is displayed on the display unit 15.

[0023] Figure 3 is a flowchart illustrating the vibration location estimation method performed by the vibration analysis processing device 10. [Step S1] Understanding the positional relationship between the fiber and the road The positional relationship between the optical fiber cable 50 and the road or ocean is understood. The position of the fiber length in the longitudinal direction of the optical fiber cable 50 laid above the road, on the road surface, or underground is investigated to determine where it is laid on the road. It may be the ocean instead of a road. [Step S2] Vibration acquisition The vibration transmitted to the optical fiber cable 50 is measured for a certain period of time using the DAS of the vibration measuring instrument 20. The vibration data measured for a certain period of time is input from the input unit 11. [Step S3] Frequency component analysis (Sub-step S3-1) The calculation processing unit 12 divides the vibration data acquired in step S2 into arbitrary points (sections) and arbitrary time intervals (e.g., 1 second). Figure 4 shows the time-series data of the vibration data for an arbitrary time (1 second from 0 to 1 second) at an arbitrary point X (distance X [m] from the vibration measuring instrument 20 in the longitudinal direction of the optical fiber cable 50). The arithmetic processing unit 12 performs frequency analysis on this time-series data and calculates the vibration frequency spectrum for each position (section) along the longitudinal direction of the optical fiber cable 50 (Figure 5). (Small step S3-2) The arithmetic processing unit 12 extracts only an arbitrary band (e.g., 20-80 Hz) from the vibration frequency spectrum for each position (section), divides the extracted band into arbitrary bandwidths (e.g., 3 Hz), and calculates the average value of the spectral intensity for each divided band. Figure 6 shows the result (band power series) of extracting only the data in the 20-80 Hz band from the frequency spectrum of Figure 5, dividing it into 3 Hz intervals, and calculating the average value. (Small step S3-3) The arithmetic processing unit 12 creates a series of the calculated spectral intensity average values ​​arranged in order of frequency, and compares the magnitude of each data in each band of the series data with the data adjacent to it in the frequency direction (Figure 7 left). If a bandwidth data is larger than adjacent data by a predetermined ratio (e.g., three times) or more, that bandwidth data is designated as the bandwidth data suspected of generating anomalous vibrations, while bandwidth data that does not exceed the aforementioned ratio is designated as the bandwidth data not suspected of generating anomalous vibrations.Figure 7 illustrates the process of creating suspected anomalous vibration band data / suspected anomalous vibration occurrence band data (unit flag sequence) for each band at the relevant point or section and for an arbitrary time (0-1 second). In this figure, adjacent band data are compared from the table in Figure 6, and if there is data that is three times or more larger, it is marked as "Yes" as suspected anomalous vibration band data. Other data are marked as "No". At this time, the comparison can be made with either the band adjacent to the band being compared on the lower or higher frequency side, or both. (Small step S3-4) If one or more bands become suspected anomalous vibration occurrence band data, the calculation processing unit 12 sets the sequence data as the suspected anomalous vibration sequence. As shown in Figure 7, the 23-26 Hz data is the suspected anomalous vibration occurrence band, so the suspected anomalous vibration sequence for 0-1 second in the section of distance X [m] becomes "Yes" (Figure 8).

[0024] [Step S4] Creation of a bit sequence indicating the presence or absence of anomalous vibration (Sub-step S4-1) The arithmetic processing unit 12 performs the anomalous vibration suspicion determination on vibration data acquired for each fiber distance (point or section) over an arbitrary time (e.g., 30 seconds). If any percentage (e.g., 70%) or more of the sequence data included in the time are sequences suspected of anomalous vibration, the longitudinal position (point or section) of the optical fiber cable 50 is designated as the location suspected of anomalous vibration. Figure 9(A) is a table showing sequences suspected of anomalous vibration in a section of distance X [m] arranged in order of measurement time. In the section of distance X+3, the time for "Yes" exceeds 70%, so the point or section at distance X [m] is designated as the location suspected of anomalous vibration. The arithmetic processing unit 12 performs the above process at all data acquisition positions along the entire length or a portion of the desired range of the optical fiber cable 50 in the longitudinal direction. (Small step S4-2) Subsequently, the arithmetic processing unit 12 assigns a bit "1" to the location (point or section) that was suspected of being affected by the unusual vibration and a bit "0" to the location (point or section) that was not suspected of being affected by the unusual vibration in the sequence data with the horizontal axis representing the longitudinal distance of the optical fiber cable 50 (Figure 9(B) "Bit assignment operation"). The sequence data with the horizontal axis representing the longitudinal distance of the optical fiber cable 50 and the vertical axis representing bits related to the suspected location of the unusual vibration is called the unusual vibration presence / absence bit sequence (Figure 9(C)).

[0025] [Step S5] The calculation processing unit 12 calculates a moving average of an arbitrary number of points (for example, 10 points) in the longitudinal direction of the optical fiber for the singular vibration presence / absence bit sequence (Figure 10(A)) created in step S4 (Figure 10(B)). This moving average value is defined as the singular vibration presence / absence coefficient. The calculation processing unit 12 creates a series of data (judgment value series) with the distance in the longitudinal direction of the optical fiber on the horizontal axis and the singular vibration presence / absence coefficient on the vertical axis (Figure 10(C)). [Step S6] The threshold exceedance judgment processing unit 12 detects the distance in the longitudinal direction of the optical fiber that exceeds an arbitrary threshold (for example, 0.8) in the series of data (judgment value series) of the singular vibration presence / absence coefficient calculated in step S5, and estimates the point or range in the longitudinal direction of the optical fiber that exceeds the threshold as the singular vibration occurrence location. [Step S7] The anomalous vibration location estimation processing unit 12 estimates where the anomalous vibration location is by correlating the distance of the optical fiber cable 50, for which the presence or absence coefficient of anomalous vibration recorded in step S6 was confirmed to exceed a threshold, with the relationship between the position of the fiber length in the longitudinal direction of the optical fiber cable 50 and the position of the road, which was grasped in step S1.

[0026] The arithmetic processing unit 12 may output the waveform shown in Figure 10(C) to the display unit 15 from the output unit 14, or it may output data indicating the anomalous vibration section. Alternatively, the arithmetic processing unit 12 may query the identification unit 13 for the distance of the anomalous vibration section (the distance of the optical fiber cable 50 from the vibration measuring instrument 20), and output the map location corresponding to the distance answered by the identification unit 13, along with map data, to the display unit 15 from the output unit 14. The display unit 15 displays this information to the operator. Based on the displayed information, the operator can recognize the specific vibration location occurring in the optical fiber cable 50 as the location where the event occurred.

[0027] The basic operation of the vibration analysis processing device described above is characterized by representing the locations where vibrations with unique frequency components are transmitted through the optical fiber cable using a "singular vibration presence / absence bit sequence" as shown in Figure 9(C), and then determining the locations where the singular vibrations occur using a "singular vibration presence / absence coefficient sequence" as shown in Figure 10(C), which is obtained by moving average of the bit sequence.

[0028] Specifically, this basic operation is characterized by: using DAS to acquire vibrations transmitted to optical fiber cables laid along a road; dividing the acquired vibration data into fixed time intervals and analyzing them; determining the locations where anomalous vibrations are transmitted based on whether a certain proportion of anomalous frequency components are included in the divided vibration data over time; creating a bit sequence indicating the presence or absence of anomalous vibrations, where "1" represents locations where anomalous vibrations are transmitted and "0" represents locations where they are not transmitted, relative to the longitudinal distance of the optical fiber cable; calculating a moving average of an arbitrary window size in the distance direction of the sequence data; and determining the locations or ranges where the value of the moving average exceeds an arbitrary threshold as the locations where anomalous vibrations occur.

[0029] Vibrations characterized by "vibrations with a unique frequency peak that persist for a certain period of time" are rarely found as natural vibrations and are highly likely to be caused by unusual events such as construction work. The key point of this basic operation is to estimate the location of the unique vibration by observing this characteristic using vibration measurement with DAS.

[0030] This basic operation makes it possible to provide a system for estimating the location of events accompanied by peculiar vibrations while reducing the influence of the optical fiber installation environment. In other words, this basic operation can perform peculiar vibration location determination without being affected by the magnitude of acquired vibrations due to the different vibration propagation characteristics of each road, as was the case with conventional systems.

[0031] (Embodiment) The unique vibration source identification system of this embodiment has the same configuration as described in Figure 1, and the vibration analysis processing device 10 of this embodiment has the same configuration as described in Figure 2. The vibration analysis processing device 10 includes an input unit 11 to which vibration data transmitted to the optical fiber cable 50 measured by the vibration measuring instrument 20 is input, and a calculation processing unit 12 that performs preparation and monitoring processes. The arithmetic processing unit 12, in the preparation step, divides the vibration data into a plurality of sections in the distance direction of the optical fiber cable, generates a unit flag sequence for each section and per unit time, assigning a flag to each of the vibration data in each section to indicate whether or not vibration is occurring in each bandwidth, and generates a reference flag sequence for each section by calculating the logical OR in the time direction for each bandwidth of the unit flag sequence. In the monitoring step, it generates the unit flag sequence for each section and per unit time, compares the unit flag sequence with the reference flag sequence for the section corresponding to the unit flag sequence for each unit flag sequence, and generates a modified flag sequence that modifies the frequency components for which both have the same flag to indicate that vibration is not occurring, and generates a bit sequence that represents in bits the sections in which the modified flag sequence containing a flag indicating that vibration is occurring in any of the bandwidths exists at a predetermined rate or higher, and other sections. The process involves generating a series of determination values ​​by arranging moving average values ​​calculated with an arbitrary window size in the distance direction for the bit sequence, and detecting a point or range within the determination value series where the moving average value exceeds an arbitrary threshold.

[0032] Figure 11 is a flowchart illustrating the vibration location estimation method performed by the vibration analysis processing device 10 in this embodiment. This vibration location estimation method differs from the basic operation described in Figure 3 in that it obtains reference data from vibration data under normal conditions in advance, and during monitoring, it compares this with the reference data to determine whether or not there are different vibrations. Steps S11 to S14 are preparation steps, and steps S15 to S1b are monitoring steps.

[0033] [Step S11] Understanding the positional relationship between the fiber and the road This step is the same as step S1 in Figure 3. [Step S12] Acquiring vibrations under normal conditions When it can be determined that no unusual events have occurred on the route in which the optical fiber cable 50 is laid (for example, late at night or during periods when road construction or building construction is suspended), vibrations transmitted to the optical fiber cable (for example, waves crashing on the coast or vibrations from rivers) are measured using DAS at any time.

[0034] [Step S13] The calculation processing unit 12, which calculates the band power sequence for each unit time, performs frequency analysis on the time-series data (Figure 4) for an arbitrary time (1 second from 0 to 1 second) at an arbitrary point X from the vibration data acquired in step S2, as explained in sub-step S3-1, and calculates the vibration frequency spectrum for each position (section) in the longitudinal direction of the optical fiber cable 50 (Figure 5). As explained in sub-step S3-2, the calculation processing unit 12 extracts only an arbitrary band (e.g., 20-99 Hz) from the vibration frequency spectrum for each position (section), divides the extracted band into arbitrary bandwidths (e.g., 3 Hz), and calculates the average value of the spectral intensity for each divided band. Figure 12 shows the result of extracting only the data in the 20-99 Hz band from the frequency spectrum of Figure 5, dividing it into 3 Hz intervals, and calculating the average value. Here, the calculation processing unit 12 creates a sequence of the calculated spectral intensity average values ​​arranged in order of frequency. This sequence of average values ​​is called the "band power sequence". Since Figure 4 shows the vibration data for 0 to 1 second, Figure 12 is the "band power sequence limited to 0-1 seconds". The processing unit 12 creates band power sequences for other time points as well.

[0035] [Step S14] Creation of Reference Flag Sequence (Sub-step S14-1) Figure 13 is a diagram illustrating the process of creating suspected anomalous vibration band data / suspected anomalous vibration occurrence band data (unit flag sequence) for each band at the relevant point or section and for an arbitrary time (0-1 seconds). As explained in sub-step S3-3, the arithmetic processing unit 12 compares the magnitude of the data for each band of the band power sequence for each unit time created in step S13 with the data adjacent to it in the frequency direction. At this time, the comparison may be made with either the band adjacent to the band being compared on the lower or higher frequency side, or with both. If the data is larger than the adjacent data by a predetermined ratio (e.g., 5 times) or more, a flag (e.g., "Yes") is assigned to that band data to indicate that it is a normal anomalous vibration occurrence band, and a flag (e.g., "No") is assigned to the band data that does not exceed the ratio to indicate that it is a normal non-anomalous vibration occurrence band, creating a sequence of data (right table in Figure 13). This sequence of data is called the normal unit time flag sequence (unit flag sequence). (Sub-step S14-2) The arithmetic processing unit 12 performs the unit flag sequence creation process of sub-step S14-1 for vibration data at other times as well, creating a flag sequence for the entire measurement time under normal conditions (left table in Figure 14). Then, the arithmetic processing unit 12 creates a sequence by calculating the logical OR in the time direction for each band of the flag sequence for the entire measurement time under normal conditions (right table in Figure 14). This sequence obtained by calculating the logical OR is called the reference flag sequence (at X [m]) for each point or section. (Sub-step S14-3) The arithmetic processing unit 12 performs the process of sub-step S14-2 at all data acquisition locations along the entire length or a portion of the longitudinal direction of the optical fiber, and arranges the created reference flag sequences for each point by distance to create a reference flag sequence for the entire length of the optical fiber cable (Figure 15).

[0036] [Step S15] When the vibration acquisition route is being monitored (monitoring process), the vibration transmitted through the optical fiber cable 50 is measured using DAS. As explained in step S13, the arithmetic processing unit 12 performs frequency analysis on the time series data (1 second from 0 to 1 second) at an arbitrary point X from the vibration data acquired in step S2, and calculates the vibration frequency spectrum for each position (section) in the longitudinal direction of the optical fiber cable 50. [Step S16] Creation of unit flag series for each point (sub-step S16-1) As explained in sub-step S3-2, the arithmetic processing unit 12 extracts only an arbitrary band (e.g., 20-99 Hz) from the vibration frequency spectrum for each position (section), divides the extracted band into arbitrary bandwidths (e.g., 3 Hz), and calculates the average value of the spectral intensity for each divided band. Figure 16 shows the result (band power series) of extracting only the data in the 20-99 Hz band from the frequency spectrum, dividing it into 3 Hz intervals, and calculating the average value. Figure 16 is the "limited band power sequence for 0-1 seconds". The arithmetic processing unit 12 creates band power sequences for other time periods as well. (Sub-step S16-2) Figure 17 is a diagram illustrating the process of creating suspected anomalous vibration band data / suspected anomalous vibration occurrence band data (unit flag sequence) for each band at the relevant point or section and for an arbitrary time (0-1 seconds). As explained in sub-step S3-3, the arithmetic processing unit 12 compares the magnitude of the data for each band in the band power sequence for each unit time created in sub-step S16-1 with the data adjacent to it in the frequency direction. At this time, the comparison may be made with either the band adjacent to the band being compared on the lower or higher frequency side, or with both. If the band is larger than the adjacent data by a predetermined ratio (e.g., twice) or more, a flag (e.g., "Yes") is assigned to that band to indicate that it is an anomalous vibration occurrence band, and a flag (e.g., "No") is assigned to bands that do not exceed the ratio to indicate that they are anomalous vibration non-occurring bands, creating a sequence data (unit flag sequence) (right table in Figure 17).

[0037] [Step S17] The correction processing unit 12 using the reference flag sequence compares the time-based unit flag sequence created in step S16 (middle table in Figure 18) and the reference flag sequence created in step S14 (left table in Figure 18) at the same point or interval (e.g., X [m]) with the reference flag sequence created in step S14 (left table in Figure 18), as shown in Figure 18. Based on the comparison, the processing unit 12 records a flag indicating that the vibration is not occurring for frequency components where both flags are the same, and generates a correction flag sequence (right table in Figure 18) in which the flags of the unit flag sequence are recorded for frequency components where the flags of the unit flag sequence are different. Specifically, the processing unit 12 sets the frequency band where both flags are "Yes" to "No", and sets the frequency band where both flags are "No" and the flags of the unit flag sequence are different (frequency bands where the unit flag sequence is "Yes" and the reference flag sequence is "No", and frequency bands where the unit flag sequence is "No" and the reference flag sequence is "Yes") to no correction (the flags remain as they are in the unit flag sequence).

[0038] The following steps involve performing the sub-steps S3-4 and beyond described in the basic operation. That is, in the basic operation, the sub-steps S3-4 and beyond were performed on the "unit flag series" in the right-hand table of Figure 7, but in this embodiment, the sub-steps S3-4 and beyond are performed on the "modified unit flag series" in the right-hand table of Figure 18.

[0039] [Step S18] Calculation of suspected anomalous vibration sequence for each location or section (Sub-step S18-1) This step corresponds to the sub-step S3-4 of the basic operation. The calculation processing unit 12 determines that if one or more bands in the time-based correction unit flag sequence (right table in Figure 18) are suspected anomalous vibration bands (bands with the "Yes" flag assigned), the unit correction flag sequence for that time (e.g., 0 to 1 second) at that location or section (e.g., X [m]) is a suspected anomalous vibration sequence (e.g., "Yes"; Figure 19). Otherwise, it determines that it is not a suspected anomalous vibration sequence (e.g., "No").

[0040] (Sub-step S18-2) This step corresponds to sub-step S4-1 of the basic operation. The determination of the suspected anomalous vibration sequence is performed on the entire vibration data in the time direction (e.g., 30 seconds) at the point or section (e.g., X [m]) measured in step S15, and a sequence of the presence or absence of anomalous vibration is created for each point or section (Figure 20(A)). If any percentage (e.g., 70%) or more of the sequence of the presence or absence of anomalous vibration for each point or section becomes a suspected anomalous vibration sequence ("Yes"), that point is designated as a suspected anomalous vibration location. Figure 20(A) is a table showing the suspected anomalous vibration sequences at a point or section at a distance X [m] arranged in order of measurement time. In the section at distance X+3, the time for "Yes" exceeds 70%, so the section at distance X+3 [m] is designated as a suspected anomalous vibration location. The calculation processing unit 12 performs this operation at all data acquisition positions along the entire length of the optical fiber in the longitudinal direction or at any monitoring section. (Sub-step S18-2) This step corresponds to sub-step S4-2 of the basic operation. Subsequently, the arithmetic processing unit 12 assigns a bit "1" to the location or section suspected of being affected by the unusual vibration in the sequence data with the horizontal axis representing the longitudinal distance of the optical fiber cable 50, and a bit "0" to the location or section that was not affected by the unusual vibration ("Bit assignment operation" in Figure 20(B)). The sequence data with the horizontal axis representing the longitudinal distance of the optical fiber cable 50 and the vertical axis representing bits related to the location suspected of being affected by the unusual vibration is called the unusual vibration presence / absence bit sequence (Figure 9(C)).

[0041] [Step S19] The singular vibration presence / absence coefficient sequence creation calculation processing unit 12 calculates a moving average of an arbitrary number of points (for example, 10 points) in the longitudinal direction of the optical fiber for the singular vibration presence / absence bit sequence (Figure 21(A)) created in step S18 (Figure 21(B)). This moving average value is defined as the singular vibration presence / absence coefficient. The calculation processing unit 12 creates a sequence data (judgment value sequence) with the distance in the longitudinal direction of the optical fiber on the horizontal axis and the singular vibration presence / absence coefficient on the vertical axis (Figure 21(C)). [Step S1a] Threshold exceedance judgment calculation processing unit 12 detects the distance in the longitudinal direction of the optical fiber that exceeds an arbitrary threshold (for example, 0.8) in the sequence data (judgment value sequence) of singular vibration presence / absence coefficient calculated in step S19, and estimates the point or range in the longitudinal direction of the optical fiber that exceeds the threshold as the singular vibration occurrence location. [Step S1b] The anomalous vibration location estimation processing unit 12 estimates where the anomalous vibration location is by correlating the distance of the optical fiber cable 50, for which the presence or absence coefficient of anomalous vibration recorded in step S1a was confirmed to exceed a threshold, with the relationship between the position of the fiber length in the longitudinal direction of the optical fiber cable 50 and the position of the road, which was grasped in step S11.

[0042] The arithmetic processing unit 12 may output the waveform shown in Figure 21(C) to the display unit 15 from the output unit 14, or it may output data indicating the anomalous vibration section. Alternatively, the arithmetic processing unit 12 may query the identification unit 13 for the distance of the anomalous vibration section (the distance of the optical fiber cable 50 from the vibration measuring instrument 20), and output the map location corresponding to the distance answered by the identification unit 13, along with map data, to the display unit 15 from the output unit 14. The display unit 15 displays this information to the operator. Based on the displayed information, the operator can recognize the specific vibration location occurring in the optical fiber cable 50 as the location where the event occurred.

[0043] The vibration analysis processing device described above is characterized by its ability to represent locations where vibrations with unique frequency components are transmitted through an optical fiber cable using a "unique vibration presence / absence flag sequence," referencing a reference flag sequence to correct flags indicating that specific vibrations occur regularly to "none," and then using a moving average of these flags to determine the locations where unique vibrations occur using a "unique vibration presence / absence coefficient sequence."

[0044] Specifically, the vibration analysis processing device of the present embodiment measures in advance the location where a "specific frequency peak occurring in a normal state" is observed and the band in which the specific frequency peak is observed, using an optical fiber cable laid along the detection target route and a vibration measuring device, and stores the measurement results as reference data in the normal state. By detecting that the vibration data measured in the monitoring state contains "vibrations with specific frequency peaks" not recorded in the reference data in the normal state and the positions thereof, it is characterized by estimating the location of an event accompanied by new specific vibrations such as construction work.

[0045] According to the present invention, it is possible to perform specific vibration position determination without being affected by the magnitude of the acquired vibration due to the unique vibration propagation characteristics different for each road and the influence of steady vibrations having specific frequency peaks generated by artificial structures or the like.

[0046] 10: Vibration analysis processing device 11: Input unit 12: Arithmetic processing unit 13: Specifying unit 14: Output unit 15: Display unit 20: Vibration measuring device 40: Road 50: Optical fiber cable

Claims

1. A vibration analysis processing apparatus comprising: an input unit into which vibration data transmitted to an optical fiber cable measured by a vibration measuring instrument is input; and a calculation processing unit that performs a preparation step and a monitoring step, wherein the calculation processing unit, in the preparation step, divides the vibration data into a plurality of sections in the distance direction of the optical fiber cable, generates a unit flag sequence for each section and per unit time, assigning a flag to each of the vibration data in each section to indicate whether or not vibration is occurring in each bandwidth, and generates a reference flag sequence for each section by calculating the logical OR in the time direction for each bandwidth of the unit flag sequence, in the monitoring step, generates the unit flag sequence for each section and per unit time, compares the unit flag sequence with the reference flag sequence for the section corresponding to the unit flag sequence, and generates a modified flag sequence that modifies the frequency components for which both have the same flag to indicate that vibration is not occurring, and generates a bit sequence that represents in bits the sections in which the modified flag sequence containing a flag indicating that vibration is occurring in any of the bandwidths exists at a predetermined rate or higher, and other sections. A vibration analysis apparatus characterized by generating a determination value sequence by arranging moving average values ​​calculated with an arbitrary window size in the distance direction for the bit sequence in the distance direction, and detecting a point or range in the determination value sequence where the moving average value exceeds an arbitrary threshold.

2. The arithmetic processing unit is characterized by generating the unit flag sequence by performing a flag assignment operation for each section, wherein the flag assignment operation involves: obtaining the frequency spectrum of time-series data of the vibration data at an arbitrary time; calculating the average intensity of the frequency spectrum for each band; and assigning a flag indicating "vibration present" to a band where the ratio of the average intensity with an adjacent band is greater than a predetermined value at an arbitrary time, and assigning a flag indicating "no vibration" to other bands, as described in claim 1.

3. The vibration analysis processing apparatus according to claim 1, further comprising an output unit that outputs the aforementioned location or range as the vibration generation location of the optical fiber cable.

4. The vibration analysis processing apparatus according to claim 1, further comprising: an identification unit that compares information on the route along which the optical fiber cable is laid with the distance of the point or area in the longitudinal direction of the optical fiber cable from the vibration measuring instrument to identify the geographic location of the point or area; and an output unit that outputs the geographic location.

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