Information generation device, information generation method and program

Abstract

To make it possible to acquire information suitable for identifying an event on the basis of an optical signal received from an optical fiber.SOLUTION: An information generation device is configured that comprises: a distortion velocity calculation unit that calculates a distortion velocity on the basis of an optical signal to be output from an optical fiber disposed in a prescribed environment; an oscillation velocity calculation unit that calculates an oscillation velocity on the basis of the distortion velocity; an oscillation acceleration calculation unit that calculates oscillation acceleration by differentiating the oscillation velocity; and an identification use information generation unit that uses the oscillation acceleration to generate one or more pieces of identification use information to be used in identifying a prescribed event in the environment.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an information generating device, an information generating method, and a program. [Background technology]

[0002] A technology is known in which a pattern corresponding to the traveling state of a vehicle on a road is detected based on an optical signal received from an optical communication fiber laid on the road, and the traveling state of a vehicle on the road is detected based on the detected pattern (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2020 / 116030 Summary of the Invention [Problem to be solved by the invention]

[0004] When identifying a specific event based on an optical signal received from an optical fiber, if information used to identify the event (identification use information) is generated from the optical signal, it is preferable that such identification use information can contribute to improving the accuracy of event identification.

[0005] In consideration of the above-mentioned problems, the present invention aims to provide identification and utilization information that can contribute to improving the accuracy of event identification when identifying an event using identification and utilization information based on an optical signal received from an optical fiber. [Means for solving the problem]

[0006] (1) One aspect of the present invention that solves the above-mentioned problems is an information generating device that includes a strain rate calculation unit that calculates a strain rate based on an optical signal output from an optical fiber arranged in a specified environment, a vibration velocity calculation unit that calculates a vibration velocity based on the strain rate, a vibration acceleration calculation unit that calculates a vibration acceleration by differentiating the vibration velocity, and an identification use information generation unit that uses the vibration acceleration to generate one or more identification use information for use in identifying a specified event in the environment.

[0007] (2) One aspect of the present invention is the information generating device described in (1), in which the vibration acceleration calculation unit may calculate the vibration acceleration by passing the differentiated vibration velocity through a low-pass filter.

[0008] (3) One aspect of the present invention is an information generating device as described in (1) or (2), wherein the identification / use information generating unit may generate time-series vibration information indicating changes in vibration over time for each specific position based on the vibration acceleration.

[0009] (4) One aspect of the present invention is an information generating device described in any one of (1) to (3), wherein the identification and use information generating unit may generate time-series vibration position information indicating a change in vibration position over time based on the vibration acceleration.

[0010] (5) One aspect of the present invention is an information generating device described in any one of (1) to (4), wherein the identification / usage information generating unit may generate frequency characteristic information indicating the frequency characteristics of vibration at each specific position per unit time by performing frequency analysis on the vibration acceleration per unit time.

[0011] (6) One aspect of the present invention is an information generating method in an information generating device, comprising: a strain rate calculation step in which a strain rate calculation unit calculates a strain rate based on an optical signal output from an optical fiber arranged in a specified environment; a vibration rate calculation step in which a vibration rate calculation unit calculates a vibration rate based on the strain rate; a vibration acceleration calculation step in which a vibration acceleration calculation unit calculates a vibration acceleration by differentiating the vibration rate; and an identification use information generation step in which an identification use information generation unit uses the vibration acceleration to generate one or more identification use information for use in identifying a specified event in the environment.

[0012] (7) One aspect of the present invention is a program for causing a computer to function as a strain rate calculation unit that calculates a strain rate based on an optical signal output from an optical fiber arranged in a specified environment, a vibration rate calculation unit that calculates a vibration rate based on the strain rate, a vibration acceleration calculation unit that calculates a vibration acceleration by differentiating the vibration rate, and an identification use information generation unit that uses the vibration acceleration to generate one or more pieces of identification use information to be used to identify a specified event in the environment. Effect of the Invention

[0013] According to the present invention, it is possible to obtain an effect that information suitable for identifying an event can be obtained based on an optical signal received from an optical fiber. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram illustrating an example of the overall functional configuration of an event identification system according to an embodiment of the present invention. [Diagram 2] 1 is a diagram showing an example of the configuration of an optical fiber sensor according to an embodiment of the present invention; [Diagram 3] 10A and 10B are diagrams illustrating another configuration example of the optical fiber sensor according to the present embodiment. [Figure 4] FIG. 2 is a diagram illustrating an example of a functional configuration of an event identification device according to the present embodiment. [Diagram 5] FIG. 2 is a diagram illustrating an example of the configuration of an information generating unit in the present embodiment. [Figure 6] 1 is a diagram showing a specific application example of the event identification system according to the present embodiment; [Figure 7] FIG. 13 is a diagram showing a configuration example of an optical fiber sensor as a modified example of the present embodiment. [Figure 8] FIG. 13 is a diagram showing an example of the configuration of an optical fiber sensor as another modified example of the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] <Embodiment> [Overall configuration example of an event identification system] FIG. 1 shows an example of the overall configuration of an event identification system including a configuration serving as an information generating device according to this embodiment. The event discrimination system shown in the figure includes an optical fiber 22 and an event discrimination device 300 .

[0016] In this embodiment, the optical fiber 22 is disposed in a predetermined manner in the event recognition environment ENV. Specifically, the optical fiber 22 is included in the structure of the optical fiber sensor 20, and the optical fiber sensor 20 is disposed in the event recognition environment ENV. The event recognition environment ENV is an environment in which events that are to be recognized by the event recognition system occur.

[0017] In this embodiment, the optical fiber sensor 20 is a sensor that detects vibrations and sounds generated in response to an event to be identified as a change in an optical signal. The optical fiber sensor 20 disposed in the event identification environment ENV is connected to the event identification device 300 via the end of the optical fiber 22.

[0018] The event identification device 300 is a device that identifies an event to be identified by utilizing an optical signal input from the optical fiber sensor 20. In the figure, an example in which the event identification device 300 is configured as one device is shown, but it may also be configured, for example, by multiple devices in which predetermined functions are distributed.

[0019] [Example of optical fiber sensor configuration] An example of the configuration of the optical fiber sensor 20 of this embodiment will be described with reference to Fig. 2. The optical fiber sensor 20 shown in the figure has a cylindrical resin tube 21 and an optical fiber 22 extending in the axial (pipe axis) O1 direction of the resin tube 21 within a cylindrical wall 21A of the resin tube 21. In this embodiment, the resin tube 21 is a core material.

[0020] There may be a plurality of optical fibers 22 located inside the cylindrical wall 21A. In the figure, an example in which four optical fibers 22 are provided is shown. Fig. 2 shows an example in which four optical fibers 22 are positioned at 90° intervals around the tube axis 2 in a cross section perpendicular to the axis O1. Fig. 2 also shows an example in which the four optical fibers 22 are arranged in a spiral shape centered on the axis O1. The spiral pitch P of the optical fibers 22 may be set according to the required measurement accuracy, etc.

[0021] The optical fiber sensor 20 of this embodiment has a folded portion 222 and a folded portion 223 protruding from one end edge of the resin tube 21 in the longitudinal direction (the direction of the axis O1). The folded portion 222 is a member in which the optical fiber 22a and the optical fiber 22b protruding from one end edge in the longitudinal direction of the resin tube 21 are connected to each other outside the resin tube 21 (in the direction of the axis O1 away from the resin tube 21). The optical fiber 22a and the optical fiber 22b are adjacent to each other in the circumferential direction of the resin tube 21. The folded portion 223 is a member in which the optical fiber 22c and the optical fiber 22d protruding from one end edge of the resin tube 21 are connected outside the resin tube 21. The optical fiber 22c and the optical fiber 22d are adjacent to each other in the circumferential direction of the resin tube 21. That is, in this embodiment, the optical fiber 22 protrudes from the resin tube 21 at one end in the direction of the axis O1, and has folded-back portions 222, 223 outside the resin tube 21, in which an arbitrary optical fiber 22 is connected to an arbitrary other optical fiber 22 adjacent to the arbitrary optical fiber 22 in the circumferential direction of the resin tube 21, which is the core material.

[0022] The optical fiber sensor 20 has a folded portion 229 protruding from the other end edge of the resin tube 21 in the longitudinal direction. The folded-back portion 229 is a member in which the optical fibers 22g and 22h protruding from the other longitudinal end edge of the resin wall portion 24 are connected to the outside of the resin tube 21 (in the direction away from the resin tube 21 in the direction of the axis O1). The optical fibers 22g and 22h are adjacent to each other in the circumferential direction of the resin tube 21. The optical fibers 22g and 22h protrude from the other longitudinal end edge of the resin tube 21. The optical fiber end 22e and the optical fiber end 22f do not form a folded-back portion. The optical fiber end 22e is connected to the event identification device 300.

[0023] In this embodiment, one optical fiber is folded back to form folded-back portions 222, 223, and 229, and optical fiber ends 22e and 22f are protruded from the other edge. Thus, four optical fibers 22 are positioned within the resin tube 21.

[0024] The optical fiber 22 may have a core, a clad, and a coating layer, and may generate scattered light such as Brillouin scattering or Raman scattering due to distortion or temperature of the core when discontinuous pump light such as laser light is incident on the core. For example, an optical fiber composed of a core and a clad may be suitably used as the optical fiber 22. Examples of materials for the core and the clad include plastic and quartz glass.

[0025] Examples of optical fibers include an optical fiber strand having a primary coating around the cladding, an optical fiber core having a secondary coating around the primary coating, and an optical fiber cord having a reinforcing material around the secondary coating and an outer jacket covering the reinforcing material.

[0026] The type of optical fiber 22 is not particularly limited, and can be selected according to the detection target such as strain, vibration, or sound, the detection method, the type of scattered light used during detection, etc. For example, at least one type of optical fiber selected from the group consisting of a single-mode optical fiber, a multimode optical fiber, and a polarization-maintaining optical fiber can be used.

[0027] When a plurality of optical fibers 22 are arranged in the optical fiber sensor 20, the plurality of optical fibers 22 may be the same type of optical fiber or different types of optical fibers.

[0028] 2, the optical fiber is located inside the cylindrical wall of a cylindrical resin tube. However, the present invention is not limited to this, and the optical fiber may be located outside the cylindrical wall (i.e., on the outer circumferential surface of the resin tube). In the above-described embodiment, the core material is a cylindrical resin tube, but the present invention is not limited to this. The core material does not have to be cylindrical (i.e., hollow) and may be solid. When the core material is solid, the optical fiber may be located within the core material or may be located around the periphery of the core material.

[0029] With reference to Fig. 3, a configuration example of the optical fiber sensor 20A in which the core material is solid and the optical fiber is located on the outer periphery of the core material will be described. The optical fiber sensor 20A can be used in place of the optical fiber sensor 20 in the event identification system of this embodiment. Alternatively, when multiple optical fiber sensors are provided in the event identification system of this embodiment, the optical fiber sensor 20 and the optical fiber sensor 20A may be mixed in the multiple optical fiber sensors. 3, the same parts as those in FIG. 2 are given the same reference numerals and their explanations are omitted, and the following mainly describes the differences from the optical fiber sensor 20 in FIG.

[0030] The optical fiber sensor 20A has a long rod-shaped core material 121 and an optical fiber 22 located on the outer circumferential surface of the core material 121. The optical fiber 22 draws a spiral around the axis O2. The spiral pitch P2 of the spiral drawn by the optical fiber 22 is the same as the spiral pitch P.

[0031] The core material 121 is a straight rod-like solid member. By making the core material 121 a solid member, the rigidity of the optical fiber sensor 20A can be further increased, and the detection accuracy of the displacement can be further improved. The outer diameter R2 of the core material 121 is the same as the outer diameter R of the resin pipe 21. Examples of the material of the core material 121 include a resin composition, ceramic, metal, glass, and the like.

[0032] The optical fiber 22 is fixed in close contact with the outer circumferential surface of the core material 121. Methods for fixing the optical fiber 22 to the outer circumferential surface of the core material 121 include, for example, adhesion, fusion, and tape attachment.

[0033] In the optical fiber sensor 20A, the optical fiber 22 may be fixed to the core material 121 by, for example, winding the optical fiber 22 around the core material 121 and bonding it with an adhesive.

[0034] [Example of functional configuration of event identification device] An example of the functional configuration of the event identification device 300 of this embodiment will be described with reference to FIG. In the following description, an example will be given in which the event identification device 300 is connected to one optical fiber sensor 20. Also, an example will be given in which one optical fiber sensor 20 has four optical fibers 22 each individually arranged in a spiral shape.

[0035] The event identification device 300 in the figure includes a receiving unit 301, an information generating unit 302, an event identification unit 303, and a storage unit 304. The functions of the event identification device 300 in the figure may be realized by executing a program using a CPU (Central Processing Unit) included in the event identification device 300 as hardware.

[0036] The receiving unit 301 receives an optical signal from the optical fiber 22. In this case, the receiving unit 301 is connected to the optical fiber ends 22e (22e-1, 22e-2, 22e-3, 22e-4) of the four optical fibers 22. That is, the receiving unit 301 is connected to each of the four optical fibers 22 provided in one optical fiber-carrying sensor 20.

[0037] The receiving unit 301 inputs pulsed light from the optical fiber end 22e into each of the four connected optical fibers 22. In the optical fiber 22, scattered light is generated as the input pulsed light is transmitted, and returns to the input side as return light via the same optical fiber 22. The receiving unit 301 receives the return light as an optical signal.

[0038] For example, in the event recognition environment ENV, vibrations and sounds occur in response to the occurrence of an event to be recognized. The occurrence of such vibrations and sounds affects the scattered light transmitted in the optical fiber 22 via the ground or air, and also affects the return light received by the receiving unit 301. In other words, the return light changes in response to the vibrations and sounds generated in the event recognition environment ENV.

[0039] The optical signal Sopt received by the receiving unit is input to the information generating unit 302. The information generating unit 302 generates a plurality of pieces of identification information using the input optical signal Sopt. The identification information is information used by the event identifying unit 303 to identify a target event (event identification).

[0040] The event identification unit 303 executes event identification using the multiple event identification information generated by the information generation unit 302, and outputs the identification result (event identification result). For example, the event identification unit 303 may store the event identification result in the storage unit 304. The event identification unit 303 may also output the event identification result by an external display or printer. Furthermore, data in which the event identification result obtained by the event identification unit 303 is associated with the corresponding identification utilization information may be used as teacher data for constructing a trained model used by the event identification unit 303.

[0041] The memory unit 304 stores various information related to the event identifier 300 .

[0042] [Example of information generation unit configuration] An example of the configuration of the information generating unit 302 will be described with reference to FIG. In the information generating section 302 , the optical signal S opt output from the receiving section 301 is input to a strain rate calculating section 321 .

[0043] The strain rate calculation unit 321 calculates the strain rate using the input optical signal Sopt. The strain rate indicates the rate of change in strain over time, and is generally calculated by dividing the amount of deformation (displacement) per unit time by the length before the displacement. The strain rate calculation unit 321 inputs strain rate information D1 indicating the calculated strain rate information to the vibration velocity calculation unit 322.

[0044] The vibration velocity calculation section 322 calculates the vibration velocity using the strain rate indicated by the input strain rate information D1. The vibration velocity calculation section 322 may calculate the vibration velocity using the following formula (1) used in DAS (Distributed Acoustic Sensing).

[0045]

number

[0046] The vibration velocity calculation section 322 inputs vibration velocity information D2 indicating the calculated vibration velocity to the vibration acceleration calculation section 323.

[0047] The vibration acceleration calculation section 323 calculates the vibration acceleration using the vibration velocity indicated by the input vibration velocity information D2. The vibration acceleration calculation section 323 may calculate the vibration acceleration by differentiating (for example, first-order differential) the vibration velocity. Moreover, high-frequency noise may increase due to differentiation of the vibration velocity. Therefore, the vibration acceleration calculation unit 323 may pass the vibration acceleration obtained by differentiating the vibration velocity through a low-pass filter with a predetermined cutoff frequency. The vibration acceleration calculation section 323 inputs vibration acceleration information D3 indicating the calculated vibration acceleration to the identification use information generation section 324.

[0048] The identification use information generating unit 324 generates the identification use information by using the vibration acceleration indicated by the input vibration acceleration information D3. Specifically, the identification use information generating unit 324 can generate time series waveform information D11, time series vibration position information D12, and time series frequency characteristic information D13 as the identification use information. That is, the information generating unit 302 of this embodiment can generate a plurality of pieces of identification use information from the vibration acceleration information D3.

[0049] The time-series waveform information D11 is information (an example of time-series vibration information) that indicates a change over time in a waveform corresponding to a vibration occurring at a specific position in the event identification environment ENV. The identification use information generating section 324 may generate a plurality of pieces of time-series waveform information D11 corresponding to each of a plurality of arbitrary positions defined in the event identification environment ENV, using the vibration acceleration indicated by the vibration acceleration information D3.

[0050] The time-series vibration position information D12 is information indicating a change in position of a vibration occurring in the event identification environment ENV over time. The identification use information generating section 324 may detect the occurrence of vibration based on the vibration acceleration indicated by the vibration acceleration information D3, and generate a plurality of pieces of time-series vibration position information D12 in accordance with each detected vibration.

[0051] In addition, the vibration acceleration indicated by the vibration acceleration information D3 may have a positive or negative value and may not be suitable as input data for the learning model if the value exceeds the range of ±1. Therefore, the identification and use information generating unit 324 may perform the following supplementary calculation when calculating the time-series waveform information D11 or the time-series vibration position information D12. The identification-use information generating unit 324 may, for example, normalize the vibration acceleration indicated by the vibration acceleration information D3 with a pre-event initial value. Specifically, the optical signal Sopt may have an initial value that is not zero. In this case, the identification-use information generating unit 324 may normalize the value of the vibration acceleration by subtracting the initial value. Furthermore, when obtaining learning data for the learning device to learn, the identification and use information generating unit 324 may cut out the vibration acceleration indicated by the vibration acceleration information D3 using a time window. Furthermore, the identification-use information generating unit 324 may convert the vibration acceleration indicated by the vibration acceleration information D3 into an absolute value. Furthermore, the identification-use information generating unit 324 may obtain a gain y (dB) for an arbitrary reference value (n0, m0) for the absolute value. The identification / use information generating unit 324 may clarify the feature portion by squaring the vibration acceleration indicated by the vibration acceleration information D3. The identification / use information generating unit 324 may obtain a gain y (dB) for an arbitrary reference value (n0, m0) for the value obtained by squaring. Furthermore, the identification and use information generating unit 324 may perform downsampling by thinning out the vibration acceleration indicated by the vibration acceleration information D3, calculating a moving average, or passing the vibration acceleration information D3 through a low-pass filter. In addition, in order to cope with a case where a specific portion occurs in the frequency for each vibration source, the vibration acceleration indicated by the vibration acceleration information D3 may be passed through a band-pass or high-pass filter. Furthermore, the vibration acceleration value indicated by the vibration acceleration information D3 may be normalized so as to be restricted within the range of ±1.

[0052] The time-series frequency characteristic information D13 is information indicating changes over time in frequency characteristics corresponding to vibrations occurring at specific positions in the event identification environment ENV. The identification-use information generating unit 324 cuts out the vibration acceleration indicated by the vibration acceleration information D3 using a time window, and performs FFT calculations on the section of the cut out vibration acceleration. The identification-use information generating unit 324 repeatedly executes the same process while shifting the time of the time window. The identification-use information generating unit 324 obtains time-series frequency characteristic information D13 by arranging information indicating frequency characteristics for each time obtained by such calculations according to the passage of time. The time-series frequency characteristic information D13 obtained in this way may be a spectrogram.

[0053] Furthermore, the identification and use information generating unit 324 may further execute the following processing when calculating the time-series frequency characteristic information D13. That is, the identification and use information generating section 324 may normalize the vibration acceleration indicated by the vibration acceleration information D3 with the pre-event initial value. Furthermore, the identification and use information generating unit 324 may use any time window (e.g., a Blackman-Harris window, etc.) to extract an arbitrary window length, such as a one-second window. Then, frequency information may be obtained by Fourier transform. The frequency information may be obtained as a complex number. The complex number may be converted into an absolute value, and a gain may be obtained using an arbitrary reference value for the information obtained by converting the complex number into an absolute value. Furthermore, the identification and use information generating unit 324 may shift the start point of the time window (time shift). In addition, the identification and use information generating unit 324 may set the ranges of the time windows to overlap in part. In addition, when the ranges of the time windows overlap in part, the identification and use information generating unit 324 may average the values ​​of the overlapping parts.

[0054] As described above, in the event identification system of this embodiment, the time-series waveform information D11, the time-series vibration position information D12, and the time-series frequency characteristic information D13 are generated as identification use information used for identifying an event.

[0055] The event identification section 303 can identify an event by using at least one of the three pieces of identification use information, that is, the time-series waveform information D11, the time-series vibration position information D12, and the time-series frequency characteristic information D13. That is, the event identification unit 303 may estimate an event by using any one of the time-series waveform information D11, the time-series vibration position information D12, and the time-series frequency characteristic information D13. Also, the event identification unit 303 may identify an event by using two of the time-series waveform information D11, the time-series vibration position information D12, and the time-series frequency characteristic information D13. In this way, when selectively using a part of the three pieces of identification use information, the identification use information suitable for identifying the target event is selected. Furthermore, the event identifying section 303 may identify an event by using all of the time-series waveform information D11, the time-series vibration position information D12, and the time-series frequency characteristic information D13.

[0056] When the event discrimination unit 303 discriminates an event using a plurality of pieces of discrimination-use information, it may input all of the plurality of pieces of discrimination-use information to be used to one discriminator, and the output of the one discriminator may be used as a discrimination result. Alternatively, the event discrimination unit 303 may be provided with a plurality of discriminators, and one or more pieces of predetermined discrimination-use information may be input to each of the discriminators, and the output of each discriminator may be integrated to obtain a discrimination result of the event. The event discrimination unit 303 may also be configured such that the output of another discriminator is input to a predetermined discriminator among the plurality of discriminators. As a specific example, the event discrimination unit 303 may have a first discriminator that outputs a discrimination result in response to inputs of time-series waveform information D11 and time-series vibration position information D12, and a second discriminator that outputs a final discrimination result in response to inputs of the output of the first discriminator and time-series frequency characteristic information D13.

[0057] As can be understood from the above description, in this embodiment, the identification and use information is obtained by calculating the strain rate from the optical signal Sopt, calculating the vibration velocity from the calculated strain rate, and then differentiating the calculated vibration velocity to calculate the vibration acceleration. The vibration acceleration thus obtained is suitable for generating the identification and use information, and therefore it is expected that the accuracy of the event identification result will be improved. In addition, when calculating the vibration acceleration, high-frequency noise generated by differentiating the vibration velocity is suppressed by passing it through a low-pass filter. As a result, it is possible to obtain information on the vibration acceleration with suppressed noise, and the quality of the identification and use information generated based on the vibration acceleration is improved, making it possible to improve the accuracy of the event identification result.

[0058] In addition, the event identification unit 303 of this embodiment is configured to generate multiple pieces of identification-use information, and can identify an event by combining and using two or more pieces of identification-use information from the generated identification-use information. This makes it possible to improve the accuracy of the identification result compared to when an event is identified using a single piece of identification-use information.

[0059] [Application example of event identification system] A specific application example of the event identification system of this embodiment will be described with reference to Fig. 6. In Fig. 6, the same parts as those in Fig. 1 are given the same reference numerals and the description thereof will be omitted. In the event identification system shown in the figure, an optical fiber sensor 20 is buried under a road RD along which vehicles CR such as automobiles pass. The optical fiber 22 in the optical fiber sensor 20 thus installed changes the return light in response to vibrations and sounds generated by the vehicle CR passing over the road RD. In the event discrimination device 300, the information generating unit 302 generates discrimination information (time-series waveform information D11, time-series vibration position information D12, and time-series frequency characteristic information D13) by using the return light received by the receiving unit 301. The event discriminating unit 303 outputs a final discrimination result D10 according to the input of the discrimination information.

[0060] In such an event identification system, the identification utilization information (time-series waveform information D11, time-series vibration position information D12, and time-series frequency characteristic information D13) generated by the information generation unit 302 of the event identification device 300 can be treated as information detected regarding vibrations occurring in response to a vehicle passing over a road RD, for example. In addition, the event identification unit 303 can be configured to identify events such as the passing status of the vehicle CR on the road RD and road conditions in response to the input of the identification utilization information, and to output the final identification results D10 regarding these events. As a specific example, the event identification unit 303 may generate a final identification result D10 indicating the results of identifying the speed of each vehicle CR passing through the road RD, the type of each vehicle CR passing through the road RD (e.g., passenger car, freight vehicle, motorcycle, etc.), the weight and size of each vehicle CR passing through the road RD, the unevenness of the road RD, the situation of objects such as luggage falling onto the road RD, etc.

[0061] As the event identification unit 303 in the event identification system of Fig. 6, an identification algorithm that is optimal among the identification algorithms (identification use information to be used, internal classifier configuration, etc.) may be adopted depending on the event to be identified and various conditions in the environment to be identified. Furthermore, the event identification unit 303 may be configured to switch the identification algorithm depending on a change in the event to be identified and various conditions in the environment to be identified.

[0062] The time-series waveform information D11 has a larger amplitude as the object becomes harder, heavier, and faster. In addition, when the time-series waveform information D11 is graphed on two axes, time and amplitude, it has a characteristic that it becomes pulse-like when a moving object moving at a walking speed is identified, whereas it becomes envelope-like when a moving object moving at high speed such as a vehicle CR is identified. In addition, when the time-series vibration position information D12 is graphed on two axes of time and position, a slope can be obtained with high accuracy according to the speed. In addition, the time-series vibration position information D12 has a higher intensity as the speed increases. In addition, the time-series vibration position information D12 has a characteristic that, when a moving object moving at a speed of about walking is identified, it becomes dot-like, whereas, when a moving object moving at high speed such as a vehicle CR is identified, it becomes line-like. The time-series frequency characteristic information D13 responds to hard objects up to high frequencies. The time-series frequency characteristic information D13 also has a characteristic that the frequency feature amount is likely to change in response to a change in shape such as a depression in the road RD.

[0063] In addition, from the above characteristics, the advantages of identifying each event of abnormality occurrence such as the speed, the type of the vehicle CR, the position of the vehicle CR, and the step on the road RD for the time-series waveform information D11, the time-series vibration position information D12, and the time-series frequency characteristic information D13 are derived as follows. First, the time-series vibration position information D12 is best for identifying the speed, the time-series frequency characteristic information D13 is best for identifying the type of vehicle CR, the time-series vibration position information D12 is best for identifying the position of the vehicle CR, and the time-series frequency characteristic information D13 is best for identifying the occurrence of an abnormality.

[0064] Therefore, in consideration of the advantages of each of the above identification utilization information, when the event identification system of FIG. 6 is configured to identify, for example, two objects, the speed of the vehicle CR and a step on the road RD, a identification algorithm may be constructed for the event identification unit 303 such that the time-series vibration position information D12 and the time-series frequency characteristic information D13 are identified with a higher weighting than the time-series waveform information D11.

[0065] In the event identification system of this embodiment, the events to be identified by the event identification device 300 are not limited to those based on distortion and vibration as described above. For example, the event identification device 300 may be configured to identify events related to temperature, dynamic pressure, and the like.

[0066] <Modification> Modifications of the optical fiber sensor of this embodiment will be described below. The optical fiber sensor shown as a modification can be disposed in the event recognition environment ENV in place of the optical fiber sensor 20 in FIG.

[0067] 10 shows a configuration example of an optical fiber sensor 30 as a modified example of this embodiment. The figure shows a cross section of the optical fiber sensor 30 cut along a direction perpendicular to the extension direction. The optical fiber sensor 30 in the figure includes one optical fiber 22. The optical fiber 22 is covered with a solid inner coating 31. The inner coating 31 is further covered with a solid outer coating 32. The inner coating 31 and the outer coating 32 may be formed of, for example, a resin. In the configuration shown in the figure, a portion corresponding to the core material (resin tube 21) of the optical fiber sensor 20 in Fig. 2 may be an inner coating 31 or an outer coating 32. The hardness of the inner coating 31 or the outer coating 32 serving as the core material in this embodiment may be equivalent to that of the core material (resin tube 21) of the optical fiber sensor 20, for example.

[0068] When a structure has only one optical fiber 22, such as the optical fiber-supported sensor 30 in the same figure, the receiving unit 301 in the event identification device 300 may output one optical signal output from the one optical fiber 22 to the information generating unit 302 as an optical signal Sopt.

[0069] FIG. 11 shows a configuration example of an optical fiber sensor 30A as another modified example of this embodiment. The optical fiber-carrying sensor 30A includes two optical fibers 22-1 and 22-2. For example, the optical fiber 22-1 may be used for detection (measurement), and the optical fiber 22-2 may be used for temperature compensation. The optical fiber 22-1 is covered with a solid inner coating 31-1, and the optical fiber 22-2 is covered with a solid inner coating 31-2. The inner coating 31-1 and the inner coating 31-2 are in contact with each other and are covered with a solid outer coating 32. An outer diameter R3 of the solid outer coating 32 is preferably 5 mm or more and 20 mm or less.

[0070] In the case of the optical fiber sensor 30A of this modified example, the receiving unit 301 may perform temperature compensation on the optical signal output from the optical fiber 22-1 using the optical signal output from the optical fiber 22-2, and output the temperature-compensated optical signal Sopt to the information generating unit 302.

[0071] In this embodiment, the identification and use information generated by the information generating unit 302 is not limited to the three items of the time-series waveform information D11, the time-series vibration position information D12, and the time-series frequency characteristic information D13, and the information generating unit 302 may be configured to generate more identification and use information. As an example, the information generating unit 302 may also generate information indicating a change in the intensity of vibration over time instead of the amplitude of vibration, similar to the time-series waveform information D11.

[0072] In addition, a program for realizing the function of the above-mentioned event identification device 300 may be recorded in a computer-readable recording medium, and the program recorded in the recording medium may be read into a computer system and executed to perform the processing of the above-mentioned event identification device 300. Here, "reading a program recorded in a recording medium into a computer system and executing it" includes installing the program into a computer system. The "computer system" here includes hardware such as an OS and peripheral devices. In addition, the "computer system" may include a plurality of computer devices connected via a network including the Internet, a WAN, a LAN, a dedicated line, and other communication lines. In addition, the "computer-readable recording medium" refers to a portable medium such as a flexible disk, an optical magnetic disk, a ROM, a CD-ROM, and a storage device such as an HDD or an SDD built into a computer system. In this way, the recording medium storing the program may be a non-transient recording medium such as a CD-ROM. In addition, the recording medium also includes a recording medium provided inside or outside the computer system that can be accessed from a distribution server in order to distribute the program. The code of the program stored in the recording medium of the distribution server may be different from the code of the program in a format executable by a terminal device. That is, as long as it can be downloaded from a distribution server and installed in a form executable by a terminal device, the format in which it is stored in the distribution server does not matter. The program may be divided into multiple parts, downloaded at different times, and then combined on the terminal device, or each of the divided programs may be distributed by a different distribution server. Furthermore, the "computer-readable recording medium" includes a program that holds a program for a certain period of time, such as a volatile memory (RAM) inside a computer system that becomes a server or a client when a program is transmitted via a network. The program may also be a program for realizing part of the above-mentioned functions. Furthermore, the program may be a so-called difference file (difference program) that can realize the above-mentioned functions in combination with a program already recorded in the computer system. [Explanation of symbols]

[0073] 20, 20A, 30, 30A Optical fiber carrying sensor, 22, 22-1, 22-2 Optical fiber, 31, 31-1, 31-2 Inner coating, 32 Outer coating, 121 Core material, 300 Event identification device, 301 Receiving unit, 302 Information generation unit, 303 Event identification unit, 304 Memory unit, 321 Velocity calculation unit, 322 Vibration velocity calculation unit, 323 Vibration acceleration calculation unit, 324 Identification utilization information generation unit

Claims

1. a strain rate calculation unit that calculates a strain rate based on an optical signal output from an optical fiber disposed in a predetermined environment; A vibration velocity calculation unit that calculates a vibration velocity based on the strain velocity; a vibration acceleration calculation unit that calculates a vibration acceleration by differentiating the vibration velocity; an identification-use information generating unit that generates one or more pieces of identification-use information used to identify a predetermined event in the environment by using the vibration acceleration; An information generating device comprising:

2. The vibration acceleration calculation unit calculates the vibration acceleration by passing the differentiated vibration velocity through a low-pass filter. The information generating device according to claim 1 .

3. The identification / use information generating unit generates time-series vibration information indicating a change in vibration over time for each specific position based on the vibration acceleration.

3. The information generating device according to claim 1 or 2.

4. The identification / use information generating unit generates time-series vibration position information indicating a change in vibration position over time based on the vibration acceleration.

3. The information generating device according to claim 1 or 2.

5. The identification / use information generating unit performs a frequency analysis on the vibration acceleration for each unit time to generate frequency characteristic information indicating a frequency characteristic of the vibration for each specific position for each unit time.

3. The information generating device according to claim 1 or 2.

6. An information generation method in an information generation device, comprising: a strain rate calculation step in which a strain rate calculation unit calculates a strain rate based on an optical signal output from an optical fiber disposed in a predetermined environment; a vibration velocity calculation step in which a vibration velocity calculation unit calculates a vibration velocity based on the strain velocity; a vibration acceleration calculation step in which a vibration acceleration calculation unit calculates a vibration acceleration by differentiating the vibration velocity; an identification-use information generating step of generating one or more pieces of identification-use information used to identify a predetermined event in the environment by using the vibration acceleration; An information generating method comprising:

7. Computer, a strain rate calculation unit that calculates a strain rate based on an optical signal output from an optical fiber disposed in a predetermined environment; a vibration velocity calculation unit that calculates a vibration velocity based on the strain velocity; a vibration acceleration calculation unit that calculates a vibration acceleration by differentiating the vibration velocity; an identification-use information generating unit that generates one or more pieces of identification-use information used to identify a predetermined event in the environment by using the vibration acceleration; A program to function as a

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