JP2022085115A - Phase unwrapping program, phase unwrapping device, and phase unwrapping method - Google Patents

Abstract

To provide a phase unwrapping program with which it is possible to make corrections to 2π or greater phase changes.SOLUTION: The present invention executes: a process of acquiring the data sequence of a phase difference caused by elongation/shrinkage of an optical fiber, regarding each sampling position of the optical fiber; a first process of performing phase unwrapping upon a first data sequence acquired regarding a first sampling position where phase wrapping is occurring and obtaining a second data sequence; and a second process of correcting, using a third data sequence acquired regarding a second sampling position that is lower in sensitivity to vibration than the first sampling position and at which a data sequence is acquired that has a prescribed degree of correlation between the first data sequence and itself, the data of the second data sequence so that the coefficient of correlation between the second and the third data sequences further increases, or correcting the data of the second data sequence so that an error between a model created from the third data sequence and a frequency response function and the second data sequence decreases.SELECTED DRAWING: Figure 8

Description

The present invention relates to a phase unwrapping processing program, a phase unwrapping processing apparatus, and a phase unwrapping processing method.

DAS (Distributed Acoustic Sensor) or DVS (Distributed Vibration Sensor), a technique for measuring vibration accompanied by deformation of the optical fiber scattering position, is known from the coherent of the rear Rayleigh scattered light when an optical pulse is applied to the optical fiber (Distributed Vibration Sensor). For example, see Patent Documents 1 to 3). The DAS can acquire vibration information at each position of the optical fiber at the periodic timing of the laser pulse. DAS is mainly used for pipeline monitoring and geological surveys. Since DAS uses the principle of the interferometry, the phase difference of π or more is folded and wrapped and measured. A method of performing phase unwrapping on a wrapped measured value is disclosed in Non-Patent Document 1 and the like.

JP-A-2019-52938 Special Table 2018-504603 Special Table 2019-504323 Gazette

Itoh, K. 1982. Analysis of the phase unwrapping algorithm. Appl. Opt. 21: 14 2470

However, in the above phase unwrapping, it is difficult to correct for a phase change of 2π or more.

In one aspect, it is an object of the present invention to provide a phase unwrapping processing program, a phase unwrapping processing apparatus, and a phase unwrapping processing method capable of performing correction for a phase change of 2π or more.

In one embodiment, the phase unwrapping processing program causes the computer to acquire a data string of the phase difference caused by the expansion and contraction of the optical fiber at each sampling position of the optical fiber, and the first sampling in which phase wrap occurs. The first process of obtaining the second data string by performing phase unwrapping on the first data string acquired for the position, and the first data string having lower sensitivity to vibration than the first sampling position. The correlation coefficient between the second data string and the third data string is larger by using the third data string acquired for the second sampling position where the data string having a predetermined degree of correlation between the two is acquired. The data in the second data string is modified so that the data in the second data string becomes smaller, or the error between the model created from the third data string and the frequency response function and the second data string becomes smaller. The second process of modifying the data of is executed.

Correction can be performed for a phase change of 2π or more.

(A) is a schematic diagram showing the overall configuration of the vibration measuring device, and (b) is a block diagram for explaining the hardware configuration of the arithmetic unit. It is a figure for demonstrating the detail of vibration measurement. It is a figure which illustrates the time series phase data stored in the storage part. (A) is a diagram illustrating the phase difference at a specific sampling position, (b) is a diagram illustrating the phase difference of (a) being phase-wrapped, and (c) is a diagram illustrating the phase of (b). It is a figure which illustrates the phase unwrap processing about the wrapping result. It is a waterfall diagram of a phase difference. It is a flowchart which illustrates an example of the phase unwrapping method of a vibration measuring apparatus. (A) to (d) are diagrams for explaining the details of the phase unwrapping method. (A) to (d) are diagrams for explaining the details of the phase unwrapping method. It is a figure which illustrates the table stored in the storage part. It is a figure for demonstrating the optimization process which increases the correlation coefficient. It is a flowchart which exemplifies another example of the phase unwrapping method of a vibration measuring apparatus. It is a figure which illustrates the table stored in the storage part. (A) to (c) are diagrams for explaining phase unwrapping by a transfer function. It is a figure which illustrates the vibration measurement system. It is a figure which illustrates the vibration measurement system.

Hereinafter, embodiments will be described with reference to the drawings.

(First Embodiment)
FIG. 1A is a schematic view showing the overall configuration of the vibration measuring device 100. As illustrated in FIG. 1A, the vibration measuring device 100 includes a measuring device 10, an arithmetic unit 20, an optical fiber 30, a display device 40, and the like. The measuring machine 10 includes a laser 11, an optical circulator 12, a detector 13, and the like. The arithmetic unit 20 includes an instruction unit 21, a vibration measurement unit 22, a storage unit 23, a first data acquisition unit 24, a first unwrapping unit 25, a second data acquisition unit 26, a second unwrapping unit 27, an analysis unit 28, and the like. To prepare for.

FIG. 1B is a block diagram for explaining the hardware configuration of the arithmetic unit 20. As illustrated in FIG. 1B, the arithmetic unit 20 includes a CPU 101, a RAM 102, a storage device 103, an interface 104, and the like. Each of these devices is connected by a bus or the like. The CPU (Central Processing Unit) 101 is a central processing unit. The CPU 101 includes one or more cores. The RAM (Random Access Memory) 102 is a volatile memory that temporarily stores a program executed by the CPU 101, data processed by the CPU 101, and the like. The storage device 103 is a non-volatile storage device. As the storage device 103, for example, a ROM (Read Only Memory), a solid state drive (SSD) such as a flash memory, a hard disk driven by a hard disk drive, or the like can be used. By executing the vibration measurement program stored in the storage device 103 by the CPU 101, the arithmetic unit 20 has an instruction unit 21, a vibration measurement unit 22, a storage unit 23, a first data acquisition unit 24, and a first unwrapping unit 25. , The second data acquisition unit 26, the second unwrapping unit 27, the analysis unit 28, and the like are realized. Each part of the arithmetic unit 20 may be hardware such as a dedicated circuit.

The laser 11 is a light source such as a semiconductor laser, and emits laser light in a predetermined wavelength range according to the instruction of the instruction unit 21. In the present embodiment, the laser 11 emits an optical pulse (laser pulse) at predetermined time intervals. The optical circulator 12 guides the optical pulse emitted by the laser 11 to the optical fiber 30 to be measured for vibration, and guides the backward scattered light returned from the optical fiber 30 to the detector 13.

The optical pulse incident on the optical fiber 30 propagates in the optical fiber 30. The optical pulse gradually attenuates while generating forward scattered light traveling in the propagation direction and backscattered light (return light) traveling in the feedback direction, and propagates in the optical fiber 30. The backscattered light re-enters the optical circulator 12. The backscattered light incident on the optical circulator 12 is emitted to the detector 13. The detector 13 is, for example, a receiver for obtaining a phase difference from the locally transmitted light.

FIG. 2 is a diagram for explaining the principle of vibration measurement. As illustrated in FIG. 2, a laser pulse is incident on the optical fiber 30 as incident light. Of the backward scattered light, the coherent light of the return light, which is Rayleigh scattered light having the same frequency as the incident light, shifts in phase due to vibration and returns to the optical circulator 12. The vibration measuring unit 22 creates time-series data (hereinafter referred to as time-series phase data) of the phase difference caused by the expansion and contraction of the optical fiber 30 at each sampling position based on the detection result of the detector 13. The phase difference caused by the expansion and contraction of the optical fiber 30 is, for example, a phase difference caused by a change in time, a phase difference caused by a change in location, a phase difference between incident light and backscattered light, and the like. The storage unit 23 stores the time-series phase data at each sampling position created by the vibration measurement unit 22. The sampling position is a point defined at a predetermined interval or a section defined at a predetermined interval in the stretching direction of the optical fiber 30. For example, the sampling position is a point defined every 1.25 m or a section defined every 1.25 m and having a length of 1.25 m or less in the stretching direction of the optical fiber 30. Each phase difference of the time series phase data may be obtained from the phase difference detected at each point, or may be obtained from the total or average of the phase differences detected in each section. .. If the next laser pulse is oscillated before the return light scattered at the end of the optical fiber 30 returns, the return light will be mixed and correct measurement will not be possible. Therefore, the minimum period of the laser pulse is the optical fiber to be measured. Determined by length.

FIG. 3 is a diagram illustrating the time-series phase data stored in the storage unit 23. As illustrated in FIG. 3, phase difference data (radians) at each position (sampling position) of the optical fiber 30 are stored for each time.

Vibration measurement can be performed using the time series phase data at each sampling position. For example, from the time-series phase data, it is possible to calculate vibration data indicating how much each sampling position of the optical fiber 30 is displaced per unit time. This method is known as self-interferometry. The physical quantity to be measured differs depending on whether the light to be interfered is locally transmitted light or backscattered light. The former is the phase difference corresponding to the strain, and the latter is the phase difference with respect to the strain rate by taking a time difference. By acquiring the phase difference with the period of the laser pulse, it can be converted into time-series strain vibration data corresponding to the optical fiber position. If vibration data can be calculated, estimation of the position of the vibration source, estimation of the type of vibration source (earthquake type, ship type, etc.), vibration transmission speed, vibration source speed, vibration type (equipment abnormality) Vibration, normal vibration, etc.) can be estimated.

FIG. 4A is a diagram illustrating a phase difference corresponding to the above-mentioned distortion at a specific sampling position. The horizontal axis shows the elapsed time, and the vertical axis shows the phase difference corresponding to the strain. In FIGS. 4 (b) and 4 (c) below, the horizontal axis indicates the elapsed time, and the vertical axis indicates the phase difference corresponding to the strain. As illustrated in FIG. 4A, the phase difference fluctuates with the passage of time.

FIG. 4B is a diagram illustrating a phase difference of FIG. 4A with phase wrapping. The phase difference actually acquired by the vibration measuring unit 22 is as shown in FIG. 4 (b). Phase wrapping is a wrapping process that folds the phase difference within the range of −π (-3.14) to + π (+3.14). Since the measured value in FIG. 4 (b) is different from that in FIG. 4 (a), by performing phase unwrapping on the phase wrapping processing result, the measured value becomes the phase difference with respect to the actual distortion. It is required to correct.

FIG. 4C is a diagram illustrating a phase unwrap process in which the phase wrapping result of FIG. 4B is corrected by shifting the phase change amount by 2π with respect to a portion where the phase change amount exceeds π. When the phase difference changes by 2π or more, it is difficult to restore it accurately. For example, the circled portion in FIG. 4 (c) is significantly different from the waveform in FIG. 4 (a).

Here, an example of the phase unwrapping process will be described. Let s (n) be the nth phase. Let Φ be the phase wrap operator. In this case, the relationship between the following equation (1) and the following equation (2) can be obtained. k is a variable that specifies how many phases of 2π should be added.

The phase difference Δs (n) can be expressed by the following equation (3).

From the above equations (1) to (3), the relationship of the following equation (4) can be obtained.

Assuming that the phase difference is from −π to + π, the relationship of the following equation (5) is obtained.

Therefore, the relationship of the following equation (6) can be obtained.

In this way, when the phase difference is π or more, a phase difference of 2π is added. If the phase difference is -π or less, a phase difference of -2π is added.

FIG. 5 is a waterfall diagram of the phase difference. In FIG. 5, the horizontal axis represents the distance from the incident end of the optical fiber 30, the vertical axis represents the elapsed time, and the shading represents the magnitude of vibration. As for the shade, the lighter the color (whiter), the more positive distortion, that is, the greater the elongation, and the darker the color (the darker the color), the more the negative distortion, that is, the greater the shrinkage. In the example of FIG. 5, a natural earthquake occurs at a predetermined time. When the natural earthquake occurs, the vibration becomes large at each position of the optical fiber 30.

As an example, the expansion and contraction of the optical fiber 30 is acquired at sample intervals of several tens of centimeters to several meters. By using the waterfall diagram, the vibration measuring device 100 can easily express the propagation of vibration having a long wavelength such as a natural earthquake. Here, when measuring the phase difference due to expansion and contraction of the optical fiber 30, the sensitivity, that is, the frequency response differs depending on the material of the coating of the optical fiber 30 and the environment in which the optical fiber 30 is laid. Even in a large-scale vibration such as a natural earthquake, there are places where a large phase difference can be obtained and places where a small phase difference can be obtained. The place where a large phase difference is obtained is a place that is easily affected by environmental noise, but is a place where the sensitivity is high. The place where a small phase difference can be obtained is a place that is not easily affected by environmental noise, but has a low sensitivity. The difference in sensitivity caused by the difference in the state of the optical fiber 30 is called coupling. Where a large phase difference can be obtained, phase wrapping is easy, and where a small phase difference can be obtained, phase wrapping is difficult. In the case of large-scale vibration such as an earthquake, there is a difference in the magnitude of the phase difference, but the correlation of vibration is large.

FIG. 6 is a flowchart illustrating an example of a phase unwrapping method of the vibration measuring device 100. 7 (a) to 7 (d) and 8 (a) to 8 (d) are diagrams for explaining the details of the phase unwrapping method in this embodiment.

First, as a precondition, the sensitivity to vibration and the degree of correlation with other sampling positions are obtained in advance for each sampling position of the optical fiber 30 by using the waterfall diagram illustrated in FIG. 7A. .. FIG. 9 is a diagram illustrating a table stored in the storage unit 23. As illustrated in FIG. 9, the sensitivity to vibration and the degree of correlation between the acquired time-series data and the time-series data acquired at other sampling positions are stored for each sampling position. By referring to this table, the sensitivity to vibration is lower than that of a specific sampling position, and the degree of correlation with the time-series data acquired at the specific sampling position (for example, the degree of correlation that exceeds the threshold value). ) Can be specified for the sampling position where the time series data is acquired.

The first data acquisition unit 24 acquires time-series data at each sampling position stored in the storage unit 23 (step S1). Next, the first data acquisition unit 24 searches for the phase difference time series data that requires phase unwrapping among the time series data stored in the storage unit 23 at each sampling position (step S2). Specifically, the first data acquisition unit 24 searches for time-series data at a location where phase wrapping occurs. For example, the first data acquisition unit 24 specifies a place where the phase difference changes by + π or more, a place where the phase difference changes by −π or less, a phase singular point, and the like as a place where phase wrapping occurs. 7 (b) and 8 (a) are time-series data A of sampling positions where phase wrapping occurs.

Next, the first unwrapping unit 25 performs the phase unwrapping process described in the above equations (1) to (6) on the time series data A acquired in step S1 (step S3). FIG. 8B is a diagram illustrating the results obtained by the phase unwrapping process.

Next, the second data acquisition unit 26 acquires reference information for the time series data A from the storage unit 23 (step S4). As the reference information, time-series data having a lower sensitivity to vibration than the sampling position from which the time-series data A was acquired and having a predetermined degree of correlation with the time-series data acquired at the sampling position is acquired. It is time series data B at the sampling position. The time range width of the time series data B and each time coincide with the time series data A. 7 (c) and 8 (c) are diagrams illustrating the time series data B.

Next, the second unwrapping unit 27 further performs phase unwrapping on the phase unwrapping processing result of FIG. 7B so that the correlation coefficient between the time series data A and the time series data B becomes large. Try (step S5). FIG. 10 is a diagram for explaining an optimization process in which the correlation coefficient becomes large. As illustrated in FIG. 10, first, the correlation coefficient between the time-series data A and the time-series data B is calculated with an arbitrary window width (same time range). When the calculated correlation coefficient falls below the threshold value considering noise, the correlation coefficient is increased by adding an integral multiple of ± 2π to the data after an arbitrary time. For example, maximize the correlation coefficient. All-time data can be phase-unwrapped by correcting while shifting the position of the window.

Next, the second unwrapping unit 27 outputs the phase unwrapping result to the analysis unit 28 (step S6). The analysis unit 28 creates vibration data at each sampling position by using, for example, the time series data stored in the storage unit 23 at each sampling position and the unwrapping processing result of the second unwrapping unit 27. The analysis unit 28 collates the created vibration data with the data stored in advance in a database or the like, and stores and analyzes the data. For example, by collating the spectrum data of vibration, it is possible to determine what the vibration source is. The display device 40 displays the analysis result and the like by the analysis unit 28.

According to this embodiment, as reference information, the time-series data B at the sampling position where the sensitivity to vibration is lower than the sampling position from which the time-series data A was acquired is adopted. In the time series data B, phase wrapping is unlikely to occur. Further, the time-series data B is time-series data at the sampling position where the time-series data having a predetermined correlation degree with the time-series data acquired at the sampling position where the time-series data A is acquired is acquired. .. By performing phase unwrapping on the time-series data A so that the correlation coefficient becomes higher with respect to the time-series data B, even if the time-series data A has a phase change of 2π or more, the time is accurate. The series data A can be corrected.

In this embodiment, the vibration measuring unit 22 is an example of an acquisition unit that acquires a data string of a phase difference caused by expansion and contraction of the optical fiber at each sampling position of the optical fiber. In an example of the first processing unit, the first unwrapping unit 25 performs phase unwrapping on the first data string acquired for the first sampling position where the phase wrap occurs to obtain the second data string. be. Time series data A is an example of the first data string. The second unwrapping unit 27 is acquired for the second sampling position where a data string having a lower sensitivity to vibration than the first sampling position and having a predetermined degree of correlation with the first data string is acquired. This is an example of a second processing unit that modifies the data in the second data string so that the correlation coefficient between the second data string and the third data string becomes larger by using the third data string. The time series data B is an example of the third data string. The storage unit 23 is an example of a storage unit that stores the sensitivity to vibration at each sampling position and the degree of correlation between the data sequences of the sampling positions. The analysis unit 28 is an example of an analysis unit that creates vibration data at each sampling position using at least the result of the second processing unit. The display device 40 is an example of a display device that displays the analysis result of the vibration data created by the analysis result.

(Modification example)
FIG. 11 is a flowchart illustrating another example of the phase unwrapping method of the vibration measuring device 100.

First, as a precondition, the sensitivity to vibration and the frequency response function with other sampling positions are obtained in advance for each sampling position of the optical fiber 30 by using the waterfall diagram illustrated in FIG. 7A. back. FIG. 12 is a diagram illustrating a table stored in the storage unit 23. As illustrated in FIG. 12, for each sampling position, the sensitivity to vibration, the degree of correlation between the acquired time-series data and the time-series data acquired at other sampling positions, and the frequency response with other sampling positions. Functions and are stored. By referring to this table, the sensitivity to vibration is lower than that of a specific sampling position, and the degree of correlation with the time-series data acquired at the specific sampling position (for example, the degree of correlation that exceeds the threshold value). It becomes possible to specify the frequency response function with the sampling position from which the time series data having) is acquired.

The first data acquisition unit 24 acquires time-series data at each sampling position stored in the storage unit 23 (step S11). Next, the first data acquisition unit 24 searches for the phase difference time series data that requires phase unwrapping among the time series data stored in the storage unit 23 at each sampling position (step S12).

Next, the first unwrapping unit 25 performs the phase unwrapping process described in the above equations (1) to (6) on the time series data A acquired in step S11 (step S13).

Next, the second data acquisition unit 26 acquires reference information for the time series data A (step S14). As the reference information, time-series data having a lower sensitivity to vibration than the sampling position from which the time-series data A was acquired and having a predetermined degree of correlation with the time-series data acquired at the sampling position is acquired. It is time series data B at the sampling position. The reference information also includes a frequency response function at the sampling position of the time series data B.

Next, the second unwrapping unit 27 creates a model from the time series data B and the frequency response function (step S15). Next, the second unwrapping unit 27 attempts phase unwrapping so that the error between the time series data A and the model created in step S15 becomes small (step S16). 13 (a) to 13 (c) are diagrams illustrating phase unwrapping by a transfer function when the phase difference measured using the optical fiber 30 is regarded as a linear system. First, the second unwrapping unit 27 creates a reference model from the time series data B (FIG. 13 (b)) selected as reference information and the frequency response function, that is, the transfer function. The second unwrapping unit 27 obtains an error between the created model and the time-series data A (FIG. 13A) to which normal phase unwrapping is applied. The second unwrapping unit 27 reduces the error by adding an integral multiple of ± 2π to the data after an arbitrary time. For example, the error is minimized. FIG. 13 (c) shows the phase difference obtained by minimizing the error.

In a general transfer function, a transfer signal is often considered for an input and an output, but in this modification, a signal at a certain sampling position is used as an input signal and a signal at another sampling position is used as an output signal. There is.

Next, the second unwrapping unit 27 outputs the phase unwrapping result to the analysis unit 28 (step S17).

According to this modification, as reference information, the time-series data B at the sampling position where the sensitivity to vibration is lower than the sampling position from which the time-series data A was acquired is adopted. Further, the frequency response function of the sampling position of the time series data B is adopted. In the time series data B, phase wrapping is unlikely to occur. Further, the time-series data B is time-series data at the sampling position where the time-series data having a predetermined correlation degree with the time-series data acquired at the sampling position where the time-series data A is acquired is acquired. .. For such time-series data B, a model is created from the time-series data B and the transfer function. The model created approaches the original data of the time series data A. Therefore, by performing phase unwrapping on the time series data A so that the error with the created model becomes small, even if the time series data A has a phase change of 2π or more, the time series data A can be accurately converted. You will be able to make corrections to it.

In this modification, the second unwrapping unit 27 has a second sampling position in which a data string having a lower sensitivity to vibration than the first sampling position and having a predetermined degree of correlation with the first data string is acquired. Using the third data string obtained for, the data in the second data string is modified so that the error between the model created from the third data string and the frequency response function and the second data string is small. This is an example of the processing unit of.

(Other examples)
FIG. 14 is a diagram illustrating a vibration measurement system. As illustrated in FIG. 14, the vibration measuring system may have a configuration in which the vibration measuring device 100 is connected to the server 302 through a telecommunication line 301 such as the Internet. The server 302 is installed in a data center or the like, includes the CPU 101, RAM 102, storage device 103, interface 104, and the like shown in FIG. 1B, and realizes functions such as the analysis unit 28 of the arithmetic unit 20.

Alternatively, as illustrated in FIG. 15, the vibration measuring system may have a configuration in which the measuring device 10 is connected to the server 302 through the telecommunication line 301. In this case, the server 302 realizes the functions of each part of the arithmetic unit 20.

In each of the above examples, the phase difference obtained from the optical fiber 30 is used as the time series data B, but the time difference is not limited thereto. For example, a phase difference obtained by an external sensor such as a displacement meter or a speedometer may be used.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiment, and various modifications and variations are made within the scope of the gist of the present invention described in the claims. It can be changed.

10 Measuring machine 11 Laser 12 Optical circulator 13 Detector 20 Computing device 21 Indicator 22 Vibration measuring unit 23 Storage unit 24 1st data acquisition unit 25 1st unwrapping unit 26 2nd data acquisition unit 27 2nd unwrapping unit 28 Analysis Part 30 Optical fiber 40 Display device 100 Vibration measuring device

Claims (13)

On the computer
For each sampling position of the optical fiber, the process of acquiring the data string of the phase difference caused by the expansion and contraction of the optical fiber, and
The first process of obtaining the second data string by performing phase unwrapping on the first data string acquired for the first sampling position where the phase wrap occurs, and
Using the third data string acquired for the second sampling position, the data string that is less sensitive to vibration than the first sampling position and has a predetermined degree of correlation with the first data string is acquired. A model created by modifying the data in the second data string so that the correlation coefficient between the second data string and the third data string becomes larger, or by using the third data string and the frequency response function. A phase unwrapping processing program characterized by executing a second process of correcting the data of the second data string so that the error between the second data string and the second data string becomes smaller. In the second process, the correlation coefficient between the second data string and the third data string is calculated with an arbitrary window width, and an integer multiple of ± 2π is added after a predetermined time in the second data string. The phase unwrapping processing program according to claim 1, wherein the correlation coefficient is increased. The first aspect of the present invention is characterized in that an integral multiple of ± 2π is added after a predetermined time in the second data string so that the difference between the model and the second data string becomes small. The described phase unwrapping processing program. To the computer
One of claims 1 to 3, wherein a process of storing the sensitivity to vibration at each sampling position and the degree of correlation between the data strings between the sampling positions in the storage unit is executed. The phase unwrapping processing program described in. To the computer
The phase unwrapping process according to any one of claims 1 to 4, wherein a process of creating vibration data at each sampling position is executed using at least the result of the second process. program. To the computer
The phase unwrapping processing program according to claim 5, wherein the processing for displaying the analysis result of the created vibration data on the display device is executed. For each sampling position of the optical fiber, an acquisition unit that acquires a data string of the phase difference caused by expansion and contraction of the optical fiber, and an acquisition unit.
A first processing unit that performs phase unwrapping on the first data string acquired for the first sampling position where phase wrap occurs to obtain a second data string, and
Using the third data string acquired for the second sampling position, the data string that is less sensitive to vibration than the first sampling position and has a predetermined degree of correlation with the first data string is acquired. A model created by modifying the data in the second data string so that the correlation coefficient between the second data string and the third data string becomes larger, or by using the third data string and the frequency response function. A phase unwrapping processing apparatus comprising: The second processing unit calculates the correlation coefficient between the second data string and the third data string with an arbitrary window width, and adds an integer multiple of ± 2π after a predetermined time in the second data string. The phase unwrapping processing apparatus according to claim 7, wherein the correlation coefficient is increased. 7. The second processing unit is characterized in that an integral multiple of ± 2π is added after a predetermined time in the second data string so that the difference between the model and the second data string becomes small. The phase unwrapping processing apparatus according to. 6. The phase unwrapping processing apparatus described. The phase unwrapping according to any one of claims 7 to 10, further comprising an analysis unit that creates vibration data at each sampling position using at least the result of the second processing unit. Processing equipment. The phase unwrapping processing device according to claim 11, further comprising a display device for displaying the analysis result of the vibration data created by the analysis result. The computer
For each sampling position of the optical fiber, the process of detecting the data string of the phase difference caused by the expansion and contraction of the optical fiber, and
The first process of obtaining the second data string by performing phase unwrapping on the first data string acquired for the first sampling position where the phase wrap occurs, and
Using the third data string acquired for the second sampling position, the data string that is less sensitive to vibration than the first sampling position and has a predetermined degree of correlation with the first data string is acquired. A model created by modifying the data in the second data string so that the correlation coefficient between the second data string and the third data string becomes larger, or by using the third data string and the frequency response function. A phase unwrapping processing method comprising executing a second process of correcting the data in the second data string so that the error between the data and the second data string becomes smaller.

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