Distributed optical fiber sensing data processing method and system and storage medium

Abstract

The invention discloses a distributed optical fiber sensing data processing method and system and a storage medium, and the method comprises the steps: carrying out the amplitude demodulation and phase demodulation of optical fiber sensing data at each spatial position, and obtaining a first amplitude demodulation result and a first phase demodulation result at each spatial position; unwinding the first phase demodulation result at each spatial position to obtain a second phase demodulation result at each spatial position; based on the second phase demodulation result at each spatial position, judging whether wrong unwrapping occurs at each spatial position; and if wrong unwrapping occurs at a certain spatial position, correcting the second phase demodulation result at the spatial position by using the first amplitude demodulation result at the spatial position. Therefore, distortion elimination of the phase signal can be realized, and the signal quality is improved.

Description

Technical Field

[0001] This application relates to the field of distributed optical fiber sensing technology, and in particular to a method, system, and storage medium for processing distributed optical fiber sensing data. Background Technology

[0002] Sensing technology and communication technology are closely related; fiber optic sensing technology emerged alongside the development of fiber optic communication technology. In recent years, as sensing systems based on optical reflectometer technology have become increasingly mature, they have been widely applied in various fields such as pipeline health monitoring, rail transit monitoring, perimeter intrusion monitoring, and underwater environment monitoring.

[0003] Demodulation schemes for fiber optic sensing systems include amplitude demodulation and phase demodulation. Amplitude demodulation can quickly locate the spatial position of an event, but it cannot obtain specific information about the event. Phase demodulation is widely used and recognized in the industry due to its high sensitivity and the linear relationship between the demodulated signal and the event. However, phase demodulation is limited by its inherent range of 0 to 2π, and dewinding is required to recover the true signal. In strong noise environments, the demodulated signal is easily distorted during dewinding due to noise. Currently, only a few studies have proposed solving this problem through data post-processing, such as trend prediction-based correction of distortion points (i.e., replacing distorted points with custom values) or introducing deep learning algorithms to suppress phase errors. These methods sacrifice some information from the data to some extent and lack universality, meaning that different application scenarios require independent model training. Summary of the Invention

[0004] This application provides a method, system, and storage medium for processing distributed optical fiber sensing data to solve at least some of the problems in the related art.

[0005] This application provides a method for processing distributed optical fiber sensing data, the method comprising:

[0006] Amplitude demodulation and phase demodulation are performed on the fiber optic sensing data at each spatial location to obtain the first amplitude demodulation result and the first phase demodulation result at each spatial location.

[0007] The first phase demodulation results at each spatial location are de-wound to obtain the second phase demodulation results at each spatial location;

[0008] Based on the second phase demodulation results at each spatial location, determine whether an erroneous unwinding has occurred at each spatial location;

[0009] If an erroneous unwinding occurs at a certain spatial location, the second phase demodulation result at that spatial location is corrected using the first amplitude demodulation result at that spatial location.

[0010] Furthermore, if an erroneous unwinding occurs at a certain spatial location, the method of correcting the second phase demodulation result at that spatial location using the first amplitude demodulation result at that spatial location includes:

[0011] Determine the spatial location of the unwinding error, the first amplitude demodulation result at the spatial location of the unwinding error, and the second phase demodulation result at the spatial location of the unwinding error; wherein, the spatial location of the unwinding error is the spatial location where the erroneous unwinding occurs;

[0012] The first amplitude demodulation result and the second phase demodulation result at the unwinding error spatial location are filtered to obtain the second amplitude demodulation result and the third phase demodulation result;

[0013] Determine the displacement difference between the second amplitude demodulation result and the third phase demodulation result, and align the first amplitude demodulation result, the second amplitude demodulation result, the second phase demodulation result, and the third phase demodulation result according to the displacement difference;

[0014] Based on the amplitude of the second amplitude demodulation result and the amplitude of the third phase demodulation result, the amplitude of the first amplitude demodulation result is adjusted to obtain the third amplitude demodulation result;

[0015] Determine the unwinding error time region in the second phase demodulation result at the spatial location of the unwinding error;

[0016] The segment corresponding to the unwinding error time region in the third amplitude demodulation result is used to replace the segment corresponding to the unwinding error time region in the second phase demodulation result to obtain the corrected unwinding phase demodulation result.

[0017] Furthermore, after unwinding the first phase demodulation results at each spatial location to obtain the second phase demodulation results at each spatial location, the processing method further includes:

[0018] Detrending is performed on the first amplitude demodulation result and the second phase demodulation result at each spatial location.

[0019] Furthermore, determining whether an erroneous unwinding has occurred at each spatial location based on the second phase demodulation results at each spatial location includes:

[0020] Based on the second phase demodulation results at each spatial location, calculate the frequency spectral density of the low-frequency band and the frequency spectral density of the high-frequency band at each spatial location.

[0021] If the difference between the frequency spectral density of the low-frequency band and the frequency spectral density of the high-frequency band at a certain spatial location is greater than the limit for the difference in frequency spectral density, it is determined that an erroneous unwinding has occurred at that spatial location.

[0022] Furthermore, the filtering of the first amplitude demodulation result and the second phase demodulation result at the unwinding error spatial location to obtain the second amplitude demodulation result and the third phase demodulation result includes:

[0023] The first amplitude demodulation result and the second phase demodulation result at the unwinding error spatial location are filtered using a bandpass filter, and interference data is removed to obtain the second amplitude demodulation result and the third phase demodulation result.

[0024] The center frequency of the bandpass filter ranges from 10Hz to Fs / 4, where Fs is the repetition frequency of the light source in the distributed optical fiber sensing system that acquires the distributed optical fiber sensing data.

[0025] Furthermore, the removal of interfering data includes:

[0026] Delete the first drift interference segment at the beginning of the first amplitude demodulation result after filtering at the spatial location of the unwinding error;

[0027] Delete the second drift interference segment at the beginning of the filtered second phase demodulation result at the unwinding error spatial location.

[0028] Furthermore, determining the shift difference between the second amplitude demodulation result and the third phase demodulation result includes:

[0029] Peak finding is performed on the second amplitude demodulation result and the third phase demodulation result; wherein the interval between peaks is in the range of Fs / 2f0 to Fs / f0, where Fs is the repetition frequency of the light source in the distributed optical fiber sensing system that acquires the distributed optical fiber sensing data, and f0 is the center frequency of the bandpass filter;

[0030] Obtain the time positions of multiple peaks in the second amplitude demodulation result and the time positions of multiple peaks in the third phase demodulation result;

[0031] The average of the differences between the time positions of multiple peaks in the second amplitude demodulation result and the time positions of multiple peaks in the corresponding third phase demodulation result is calculated as the displacement difference.

[0032] Furthermore, the step of adjusting the amplitude of the first amplitude demodulation result based on the amplitude of the second amplitude demodulation result and the amplitude of the third phase demodulation result to obtain the third amplitude demodulation result includes:

[0033] Based on the standard deviation of the amplitude of the second amplitude demodulation result and the standard deviation of the amplitude of the third phase demodulation result, the amplitude of the first amplitude demodulation result is adjusted to obtain the third amplitude demodulation result; the standard deviation of the third amplitude demodulation result is consistent with the standard deviation of the amplitude of the third phase demodulation result.

[0034] Furthermore, adjusting the amplitude of the first amplitude demodulation result based on the standard deviation of the amplitude of the second amplitude demodulation result and the standard deviation of the amplitude of the third phase demodulation result includes:

[0035] Determine the first standard deviation of the amplitude of the second amplitude demodulation result;

[0036] Determine the temporal location of the unwinding error in the second phase demodulation result at the spatial location of the unwinding error;

[0037] The third phase demodulation result is divided into multiple time intervals based on the unwinding error time position;

[0038] Determine the standard deviation of the amplitude of the third phase demodulation result in each time interval, and take the mean of the standard deviations of multiple amplitudes as the second standard deviation of the third phase demodulation result;

[0039] The amplitude of the first amplitude demodulation result is scaled up to the ratio of the first standard deviation to the second standard deviation.

[0040] Furthermore, the step of replacing the segment corresponding to the unwinding error time region in the second phase demodulation result with the segment corresponding to the unwinding error time region in the third amplitude demodulation result to obtain the corrected unwinding phase demodulation result includes:

[0041] Obtain the first amplitude difference between the second amplitude demodulation result and the third phase demodulation result at the beginning position of the unwinding error time region;

[0042] Obtain the second amplitude difference between the second amplitude demodulation result and the third phase demodulation result at the end of the unwinding error time region;

[0043] Extract the segment of the third amplitude demodulation result in the unwinding error time region and replace the segment of the second phase demodulation result in the unwinding error time region by shifting the first amplitude difference vertically;

[0044] The second phase demodulation result is shifted vertically by the second amplitude difference in the segment after the unwinding error time region, so as to align with the vertically shifted third amplitude demodulation result in the segment of the unwinding error time region.

[0045] Furthermore, the processing method also includes:

[0046] The distributed optical fiber sensing data is acquired through an acquisition device, and the amplitude demodulation and phase demodulation are performed on the distributed optical fiber sensing data acquired by the acquisition device.

[0047] Furthermore, the processing method also includes:

[0048] The distributed optical fiber sensing data is acquired by a main acquisition device and an auxiliary acquisition device, respectively. The distributed optical fiber sensing data acquired by the main acquisition device is subjected to phase demodulation, and the distributed optical fiber sensing data acquired by the auxiliary acquisition device is subjected to amplitude demodulation.

[0049] Another aspect of this application discloses a distributed optical fiber sensing data processing system, including a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement a method for processing distributed optical fiber sensing data.

[0050] In another aspect, this application provides a storage medium on which a program is stored, and when the program is executed, a method for processing distributed optical fiber sensing data is implemented.

[0051] This application provides a method, system, and storage medium for processing distributed optical fiber sensing data. The method includes: performing amplitude demodulation and phase demodulation on optical fiber sensing data at various spatial locations to obtain first amplitude demodulation results and first phase demodulation results at each spatial location; unwinding the first phase demodulation results at each spatial location to obtain second phase demodulation results at each spatial location; determining whether erroneous unwinding has occurred at each spatial location based on the second phase demodulation results; and correcting the second phase demodulation result at a spatial location using the first amplitude demodulation result at that location if erroneous unwinding has occurred. This achieves phase signal distortion elimination and improves signal quality. Attached Figure Description

[0052] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0053] Figure 1a This is a two-dimensional data display diagram of distributed fiber optic sensing data. Figure 1b This is a schematic diagram of the time series at a certain spatial location.

[0054] Figure 2 This is a flowchart illustrating a method for processing distributed optical fiber sensing data according to an embodiment of this application;

[0055] Figure 3 for Figure 2 A schematic diagram of one embodiment of step 40 in the distributed optical fiber sensing data processing method 1 shown;

[0056] Figure 4 This is a flowchart illustrating a distributed optical fiber sensing data processing method 1 according to another embodiment of this application;

[0057] Figure 5 for Figure 2 The flowchart of step 30 in the method 1 for processing distributed optical fiber sensing data is shown.

[0058] Figure 6 for Figure 3 A flowchart illustrating one implementation of step 43 in the distributed optical fiber sensing data processing method 1 shown.

[0059] Figure 7 for Figure 3 A flowchart illustrating one embodiment of step 45 in the distributed optical fiber sensing data processing method 1 shown.

[0060] Figure 8 This is a flowchart illustrating a specific embodiment of the distributed optical fiber data processing method 1 of this application;

[0061] Figure 9 A schematic diagram illustrating phase signal distortion provided in an embodiment of this application;

[0062] Figure 10 A schematic diagram illustrating the phase correction process in the embodiments of this application;

[0063] Figure 11 A schematic diagram of the frequency spectral density of the second-phase demodulation result and the third-phase demodulation result;

[0064] Figure 12 This is a schematic diagram of the structure of a distributed optical fiber data processing system according to one embodiment of this application. Detailed Implementation

[0065] This application provides a method, system, and storage medium for processing distributed optical fiber sensing data. The method, system, and storage medium are described in detail below with reference to the accompanying drawings. Unless otherwise specified, the features in the following embodiments and implementations can be combined with each other.

[0066] Please refer to Figure 1a and Figure 1b , Figure 1aThis is a two-dimensional data visualization of distributed fiber optic sensing data. The Y-axis represents the spatial axis (corresponding to spatial locations, such as 2m, 4m, ..., 100m), and the X-axis represents the time axis (corresponding to time series, with each spatial location corresponding to a set of time series). Figure 1b This is a time series diagram of a certain spatial location. Distributed fiber optic sensing data has a time series at each spatial location.

[0067] Please refer to Figure 2 , Figure 2 This is a flowchart illustrating a method 1 for processing distributed optical fiber sensing data according to an embodiment of this application. Figure 2 As shown, processing method 1 includes steps 10 to 40.

[0068] Step 10: Perform amplitude demodulation and phase demodulation on the fiber optic sensing data at each spatial location to obtain the first amplitude demodulation result and the first phase demodulation result at each spatial location.

[0069] Amplitude demodulation can only quickly pinpoint the spatial location of an event, but it cannot acquire the specific characteristics of the event. Phase demodulation, while highly sensitive and capable of restoring event details, is limited to the 0-2π phase range and requires dewinding to output the true signal.

[0070] Step 10 involves simultaneous amplitude and phase demodulation, simultaneously acquiring the first amplitude demodulation result and the first phase demodulation result. This retains the efficiency advantage of rapid positioning in amplitude demodulation while leveraging the linear characteristics of phase demodulation to provide a data foundation for subsequent detailed analysis.

[0071] Step 20: Dewind the first phase demodulation results at each spatial location to obtain the second phase demodulation results at each spatial location.

[0072] The original phase demodulation result (first phase demodulation result) is constrained by the inherent range of 0-2π, exhibiting periodic folding and failing to directly reflect the true physical changes of the event (such as continuous waveforms of vibration or linear changes in strain). Step 20 dewinds the first phase demodulation result at each spatial location. By eliminating the phase folding phenomenon, the phase signal is restored to a continuous linear signal directly related to the physical quantities of the event (such as vibration and strain) (second phase demodulation result), providing a basis for subsequent judgment on whether erroneous dewinding has occurred at the spatial location.

[0073] Step 30: Based on the second phase demodulation results at each spatial location, determine whether an erroneous unwinding has occurred at each spatial location. This allows for the location of the erroneous unwinding, enabling targeted processing of the fiber optic sensing data at that location.

[0074] Determining whether erroneous unwinding has occurred based on the second phase demodulation result is equivalent to adding a quality verification step to the unwound phase signal. By analyzing the characteristics of the second phase demodulation result, the distortion position can be accurately located, preventing erroneous second phase demodulation results from being directly used in subsequent processing. This blocks the transmission of errors from the source and ensures the accuracy of data processing.

[0075] Step 40: If an erroneous unwinding occurs at a certain spatial location, the second phase demodulation result at that spatial location is corrected using the first amplitude demodulation result at that spatial location.

[0076] Incorrect unwinding causes the second-phase demodulation result to deviate from the true physical signal (such as vibration or strain), while the first-amplitude demodulation result, although unable to provide event details, still retains relatively stable spatial characteristics and signal trends. By using the first-amplitude demodulation result at this spatial location to correct the second-phase demodulation result at that location, errors such as jumps and offsets introduced by unwinding can be eliminated, restoring the linear correlation between the phase signal and the physical quantity. In this way, phase signal distortion can be eliminated, improving signal quality.

[0077] Please refer to Figure 3 , Figure 3 for Figure 2 This is a schematic diagram of one embodiment of step 40 in the distributed optical fiber sensor data processing method 1. (See diagram for details.) Figure 3 As shown, if an erroneous unwinding occurs at a certain spatial location in step 40, the second phase demodulation result at that spatial location is corrected using the first amplitude demodulation result at that spatial location, including steps 41 to 46.

[0078] Step 41: Determine the spatial location of the unwinding error, the first amplitude demodulation result at the unwinding error spatial location, and the second phase demodulation result at the unwinding error spatial location; where the unwinding error spatial location is the spatial location where the erroneous unwinding occurred. First, locate the unwinding error spatial location, then extract the first amplitude demodulation result and the second phase demodulation result at the unwinding error spatial location. This facilitates targeted correction of the second phase demodulation result at the unwinding error spatial location using the first amplitude demodulation result.

[0079] It is understandable that if multiple spatial locations experience incorrect unwinding, the second phase demodulation result at each incorrect spatial location should be corrected accordingly.

[0080] Step 42: Filter the first amplitude demodulation result and the second phase demodulation result at the unwinding error spatial location to obtain the second amplitude demodulation result and the third phase demodulation result.

[0081] By filtering the first amplitude demodulation result and the second phase demodulation result at the unwinding error spatial location, a second amplitude demodulation result and a third phase demodulation result with relatively single frequency can be obtained. This facilitates the determination of the displacement difference between the second amplitude demodulation result and the third phase demodulation result, and the alignment of the first amplitude demodulation result, the second amplitude demodulation result, the second phase demodulation result, and the third phase demodulation result through the displacement difference.

[0082] Step 43: Determine the shift difference between the second amplitude demodulation result and the third phase demodulation result. Based on the shift difference, align the first amplitude demodulation result, the second amplitude demodulation result, the second phase demodulation result, and the third phase demodulation result. Aligning these results ensures they remain synchronized in the time series.

[0083] Step 44: Based on the amplitude of the second amplitude demodulation result and the amplitude of the third phase demodulation result, adjust the amplitude of the first amplitude demodulation result to obtain the third amplitude demodulation result. This avoids a large difference between the amplitude of the first amplitude demodulation result and the amplitude of the second phase demodulation result, which would affect the correction effect.

[0084] Step 45: Determine the unwinding error time region in the second phase demodulation result at the spatial location of the unwinding error. The unwinding error time region is also the time region near the distortion point.

[0085] Step 46: Replace the segment corresponding to the dewinding error time region in the second phase demodulation result with the segment in the third amplitude demodulation result, to obtain the corrected dewinding phase demodulation result. This eliminates phase signal distortion and improves signal quality.

[0086] Please refer to Figure 4 , Figure 4 This is a flowchart illustrating a distributed optical fiber sensing data processing method 1 according to another embodiment of this application. Figure 4 In the embodiment shown, after unwinding the first phase demodulation results at each spatial location in step 20 to obtain the second phase demodulation results at each spatial location, the processing method 1 further includes step 50.

[0087] Step 50 involves detrending the first amplitude demodulation result and the second phase demodulation result at each spatial location. This eliminates the linear increasing trend of the signal over time, reduces system errors, and improves the accuracy of error detection.

[0088] In some embodiments, detrending the first amplitude demodulation result and the second phase demodulation result at each spatial location includes: for the second phase demodulation result, selecting the longest undistorted data segment and calculating its slope k, obtaining a fitting curve with the data starting value as the baseline, and subtracting the fitting curve from the second phase demodulation result to eliminate the trend of the unwound phase signal.

[0089] For the first amplitude demodulation result, considering the complexity of the amplitude demodulation signal, a smooth fitting curve is obtained by fitting the signal. Subtracting the fitting curve from the amplitude demodulation signal yields the detrended first amplitude demodulation result.

[0090] Please refer to Figure 5 , Figure 5 for Figure 2 The flowchart shown is a schematic diagram of step 30 in method 1 for processing distributed optical fiber sensor data. (See diagram for example.) Figure 5 As shown, step 30 determines whether erroneous unwinding has occurred at each spatial location based on the second phase demodulation results at each spatial location, including steps 31 to 32. Determining whether erroneous unwinding has occurred based on the second phase demodulation results involves analyzing the second phase demodulation results and judging whether distortion has occurred based on the difference between high and low frequencies in the frequency spectral density of the unwound phase demodulation data.

[0091] Step 31: Based on the second phase demodulation results at each spatial location, calculate the frequency spectral density of the low-frequency band and the frequency spectral density of the high-frequency band at each spatial location.

[0092] Step 32: If the difference between the frequency spectral density of the low-frequency band and the frequency spectral density of the high-frequency band at a certain spatial location is greater than the frequency spectral density difference limit, it is determined that an erroneous unwinding has occurred at that spatial location. The frequency spectral density difference limit is generally selected to be greater than 10 dB. In the embodiments of this application, the low-frequency band is 0Hz-2Hz, and the high-frequency band is Fs / 5 to Fs / 2, where Fs is the repetition frequency of the light source in the distributed optical fiber sensing system that acquires distributed optical fiber sensing data.

[0093] This solution uses the objective physical quantity of spectral density difference to determine that incorrect unwinding will cause high-frequency noise components in the signal that do not correspond to the event, such as high-frequency spikes caused by phase jumps, which will cause the high spectral density to increase sharply and the difference between high and low frequencies to increase significantly. This judgment is not affected by subjective human factors and has stronger consistency.

[0094] In this embodiment of the application, step 42 filters the first amplitude demodulation result and the second phase demodulation result at the unwinding error spatial location to obtain the second amplitude demodulation result and the third phase demodulation result, including:

[0095] The first amplitude demodulation result and the second phase demodulation result at the unwinding error spatial location are filtered by a bandpass filter, and interference data is removed to obtain the second amplitude demodulation result and the third phase demodulation result.

[0096] The center frequency of the bandpass filter ranges from 10Hz to Fs / 4, where Fs is the repetition frequency of the light source in the distributed optical fiber sensing system that acquires distributed optical fiber sensing data.

[0097] Thus, the center frequency range of the bandpass filter (10Hz to Fs / 4) can be flexibly adjusted according to the characteristics of event signals in different scenarios. Compared with fixed-band low-pass or high-pass filtering, this scheme can obtain a relatively pure single-frequency signal. This facilitates the subsequent determination of the shift difference between the first amplitude demodulation result and the second phase demodulation result using the two single-frequency signals of the second amplitude demodulation result and the third phase demodulation result, and allows for the alignment of the first amplitude demodulation result and the second phase demodulation result based on the shift difference. It also facilitates the correction of the second phase demodulation result using the first amplitude demodulation result.

[0098] Too small a bandpass frequency will result in insufficient peak values ​​for subsequent operations. Too large a bandpass frequency will result in insufficient sampling points per cycle, also affecting subsequent operations. In this embodiment, the bandpass filter uses a window function of order LF = 62, a Kaiser coefficient of 0.5, a sampling rate of 10kHz (consistent with the repetition rate), a center frequency of 200Hz, and cutoff frequencies of ±25Hz (i.e., 175Hz and 225Hz).

[0099] In this embodiment of the application, deleting interfering data includes:

[0100] Delete the first drift interference segment at the beginning of the first amplitude demodulation result after filtering at the spatial location of the unwinding error;

[0101] Delete the second drift interference segment at the beginning of the filtered second phase demodulation result at the unwinding error spatial location.

[0102] The initial drift is mostly due to transient interference when the filter circuit is powered on. A data deletion operation is performed on the first amplitude demodulation result and the second phase demodulation result after bandpass filtering. Specifically, the segment from the beginning of the data segment to the LF / 2 data point is deleted. This segment is considered unusable due to the filtering operation, where LF is the filter order. This process makes the reference for subsequent correction steps cleaner and improves the reliability of the final correction result.

[0103] Please refer to Figure 6 , Figure 6 for Figure 3 The flowchart illustrates one embodiment of step 43 in the distributed optical fiber sensor data processing method 1. Figure 6 As shown, step 43 determines the shift difference between the second amplitude demodulation result and the third phase demodulation result, including steps 431 to 433.

[0104] Step 431 involves peak finding of the second amplitude demodulation result and the third phase demodulation result; wherein the interval between peaks ranges from Fs / 2f0 to Fs / f0, where Fs is the repetition frequency of the light source in the distributed fiber optic sensing system acquiring distributed fiber optic sensing data, and f0 is the center frequency of the bandpass filter. Noise signals can produce false peaks, and if the peak interval is not limited, it will lead to incorrect peak position identification. The peak interval range (Fs / 2f0 to Fs / f0) is determined by the system parameter (Fs) and the target signal frequency band (f0), which can effectively eliminate false peaks caused by noise and ensure the authenticity of the peak position. In this embodiment, the peak interval value is 40.

[0105] Step 432: Obtain the time positions of multiple peaks in the second amplitude demodulation result and the time positions of multiple peaks in the third phase demodulation result. Specifically, obtain two sets of peaks in the second amplitude demodulation result and the third phase demodulation result, and mark the time positions of the peaks in the second amplitude demodulation result and the third phase demodulation result.

[0106] Step 433: Calculate the average of the differences between the time positions of multiple peaks in the second amplitude demodulation result and the time positions of multiple peaks in the corresponding third phase demodulation result, and use this average as the displacement difference. Calculating the displacement difference using only a single peak is susceptible to noise near that peak, leading to a large error in the displacement difference. This scheme, by averaging the differences of multiple peaks, can offset the random errors of a single peak, making the displacement difference closer to the true value.

[0107] After determining the displacement difference, the first amplitude demodulation result and the second amplitude demodulation result can be moved back and forth to align the first amplitude demodulation result, the second amplitude demodulation result, the second phase demodulation result, and the third phase demodulation result.

[0108] In this embodiment of the application, step 44, based on the amplitude of the second amplitude demodulation result and the amplitude of the third phase demodulation result, adjusts the amplitude of the first amplitude demodulation result to obtain the third amplitude demodulation result, including:

[0109] Based on the standard deviation of the amplitude of the second amplitude demodulation result and the standard deviation of the amplitude of the third phase demodulation result, the amplitude of the first amplitude demodulation result is adjusted to obtain the third amplitude demodulation result; the standard deviation of the third amplitude demodulation result is consistent with the standard deviation of the amplitude of the third phase demodulation result.

[0110] The core physical meaning of standard deviation is the degree of dispersion of data, i.e., the level of fluctuation. The smaller the standard deviation, the more concentrated the data and the smaller the fluctuation. The larger the standard deviation, the more dispersed the data and the greater the fluctuation. Since the second amplitude demodulation result and the third phase demodulation result are filtered single-frequency signals, it is relatively easy to determine the standard deviations of the amplitudes of the second amplitude demodulation result and the third phase demodulation result. The standard deviation of the amplitude of the second amplitude demodulation result is consistent with that of the first amplitude demodulation result, and the standard deviation of the amplitude of the second phase demodulation result is consistent with that of the third phase demodulation result. Therefore, by adjusting the amplitude of the first amplitude demodulation result using the standard deviations of the second and third amplitude demodulation results, the third amplitude demodulation result can be obtained. The standard deviation of the third amplitude demodulation result is also consistent with that of the second phase demodulation result. This facilitates subsequent correction of the second amplitude demodulation result using the third phase demodulation result.

[0111] In some implementations, the amplitude of the first amplitude demodulation result is adjusted based on the standard deviation of the amplitude of the second amplitude demodulation result and the standard deviation of the amplitude of the third phase demodulation result to obtain the third amplitude demodulation result, including:

[0112] Determine the first standard deviation of the amplitude of the second amplitude demodulation result;

[0113] The unwinding error time location is determined in the second phase demodulation result at the spatial location of the unwinding error. In some embodiments, the unwinding error time location is determined by calculating the frequency spectral density at each time point in the second phase demodulation result.

[0114] The third-phase demodulation result is divided into multiple time intervals based on the unwinding error time position. Specifically, there are n unwinding error time positions z0, z1, ..., zn. The third-phase demodulation result is divided into n+1 time intervals according to the unwinding error time position, which means the third-phase demodulation result is divided into n+1 data segments.

[0115] Determine the standard deviation of the amplitude of the third-phase demodulation result in each time interval, and take the average of the standard deviations of multiple amplitudes as the second standard deviation of the third-phase demodulation result. Specifically, calculate the standard deviation of these n+1 data segments, and take the average of these n+1 standard deviations as the second standard deviation of the amplitude of the third-phase demodulation result.

[0116] The amplitude of the first amplitude demodulation result is scaled by the ratio of the first standard deviation to the second standard deviation. The second amplitude demodulation result is then scaled up or down by the ratio of the first standard deviation to the second standard deviation, while the first amplitude demodulation result is also scaled up or down by the ratio of the first standard deviation to the second standard deviation, to obtain the third amplitude demodulation result.

[0117] In this patent application, during amplitude correction, the filtered second amplitude demodulation result is calibrated first, and then the unfiltered first amplitude demodulation result is simultaneously corrected. The second amplitude demodulation result is filtered, clean data. By scaling it proportionally, a clean amplitude reference that perfectly matches the phase fluctuation can be obtained. Then, scaling the first amplitude demodulation result by the same proportion ensures that the fluctuation characteristics of the first amplitude demodulation result are completely consistent with the phase reference of the clean amplitude reference.

[0118] Please refer to Figure 7 , Figure 7 for Figure 3 The flowchart illustrates one embodiment of step 45 in the distributed optical fiber sensor data processing method 1. Figure 7 As shown, step 45 replaces the segment corresponding to the unwinding error time region in the second phase demodulation result with the segment corresponding to the unwinding error time region in the third amplitude demodulation result to obtain the corrected unwinding phase demodulation result. It is understood that if multiple distortion points exist, i.e., multiple unwinding error time regions, it is necessary to correct each segment corresponding to the unwinding error time region in the second phase demodulation result. This embodiment uses the correction of a segment corresponding to one unwinding error time region in the second phase demodulation result as an example. Correcting a segment corresponding to one unwinding error time region in the second phase demodulation result includes steps 451 and 454.

[0119] Step 451: Obtain the first amplitude difference between the second amplitude demodulation result and the third phase demodulation result at the beginning position of the unwinding error time region.

[0120] The second amplitude demodulation result and the third phase demodulation result are filtered single-frequency signals, which facilitates the determination of the first amplitude difference between the second amplitude demodulation result and the third phase demodulation result at the beginning position of the unwinding error time region. The first amplitude difference between the second amplitude demodulation result and the third phase demodulation result at the beginning position of the unwinding error time region is also the amplitude difference between the third amplitude demodulation result and the second phase demodulation result at the beginning position of the unwinding error time region.

[0121] Step 452: Obtain the second amplitude difference between the second amplitude demodulation result and the third phase demodulation result at the end of the unwinding error time region.

[0122] The second amplitude demodulation result and the third phase demodulation result are filtered single-frequency signals, which facilitates the determination of the second amplitude difference between the second amplitude demodulation result and the third phase demodulation result at the end position of the unwinding error time region. The first amplitude difference between the second amplitude demodulation result and the third phase demodulation result at the end position of the unwinding error time region is also the amplitude difference between the third amplitude demodulation result and the second phase demodulation result at the end position of the unwinding error time region.

[0123] Step 453: Extract the segment of the third amplitude demodulation result in the unwinding error time region and replace the segment of the second phase demodulation result in the unwinding error time region by shifting the first amplitude difference vertically. In this way, the beginning of the segment of the third amplitude demodulation result in the unwinding error time region can be connected to the beginning of the second phase demodulation result in the unwinding error time region.

[0124] Step 454: The segment of the second phase demodulation result after the unwinding error time region is shifted vertically by the second amplitude difference to align with the segment of the third amplitude demodulation result after vertical shifting within the unwinding error time region. Thus, the segment of the second phase demodulation result after the unwinding error time region can be connected to the end of the segment of the third amplitude demodulation result within the unwinding error time region.

[0125] Please refer to Figure 8 , Figure 8 This is a flowchart illustrating a specific embodiment of the distributed optical fiber data processing method 1 of this application. Figure 8 As shown, the distributed optical fiber data processing method includes: firstly, performing phase demodulation and amplitude demodulation on the distributed optical fiber sensing data, and then unwinding the phase demodulation result to obtain the unwound phase signal. Next, it is determined whether the unwound phase signal at spatial location L of the optical fiber exhibits distortion. If distortion exists, the amplitude demodulated signal and the unwound phase signal at spatial location L are selected, bandpass filtered, and data segments affected by the filtering are deleted. Peak finding is performed to obtain the peak values ​​of the filtered amplitude demodulated signal and the filtered unwound phase signal. The shift difference between the filtered amplitude demodulated signal and the filtered unwound phase signal is calculated. The unwound phase signal and the amplitude demodulated signal are aligned; the amplitude demodulated signal is amplified or reduced according to the amplitude intensity of the unwound phase signal; the corresponding segment of the adjusted amplitude demodulated signal replaces the unwound phase signal; the step transition of the data is eliminated based on the first and last values ​​of the replaced segment; and finally, the corrected unwound phase signal is output.

[0126] This application employs a simple and rapid method to process erroneous signals in phase demodulation. It eliminates the need for complex system architectures and significantly reduces computational overhead. It effectively eliminates phase errors in the unwound phase signal caused by strong background noise in phase-sensitive optical time-domain reflectometer systems. Furthermore, this solution effectively improves the signal-to-noise ratio and enhances overall signal quality. Figure 8 The process of handling distributed fiber optic sensing data allows the phase demodulation results that detect erroneous unwinding to be corrected by the amplitude demodulation results. This processing method effectively preserves the most real signal and suppresses low-frequency noise, thus maintaining the high sensitivity of phase demodulation and achieving the acquisition of high-quality signals.

[0127] In some embodiments, processing method 1 further includes:

[0128] Distributed fiber optic sensing data is acquired through a single acquisition device, and amplitude and phase demodulation are performed on this data. This allows for amplitude and phase demodulation of distributed fiber optic sensing data acquired by a single device, reducing the number of acquisition devices required and without altering the existing structure of the distributed fiber optic sensing system.

[0129] In other embodiments, processing method 1 further includes:

[0130] Distributed fiber optic sensing data is acquired by a primary acquisition device and an auxiliary acquisition device. The distributed fiber optic sensing data acquired by the primary acquisition device is subjected to phase demodulation, and the distributed fiber optic sensing data acquired by the auxiliary acquisition device is subjected to amplitude demodulation.

[0131] Amplitude demodulation only requires direct detection, while phase demodulation systems are relatively complex. Therefore, an existing acquisition device in a distributed fiber optic sensing system can be used as the main acquisition device, with an additional external acquisition device as an auxiliary acquisition device. The distributed fiber optic sensing data acquired by the auxiliary acquisition device can be directly demodulated with minimal interference.

[0132] The distributed fiber optic sensing data used for amplitude demodulation can be the same as the phase demodulation data, or it can be data collected and recorded by an auxiliary acquisition device. The auxiliary acquisition device can be placed directly on the returning backscattered Rayleigh signal link.

[0133] When a distributed fiber optic sensing system includes both a primary acquisition device and an auxiliary acquisition device, the primary and auxiliary acquisition devices can share a common path, or they can not completely share a common path. This application does not impose any restrictions on this.

[0134] Please refer to Figure 9 , Figure 9 This is a schematic diagram illustrating phase signal distortion provided in an embodiment of this application. Figure 9 In the diagram, the orange line represents the amplitude demodulation signal, i.e., the first amplitude demodulation result. The black line represents the unwound phase demodulation signal, i.e., the second phase demodulation result. The second phase demodulation result shows two obvious distortions, while the first amplitude demodulation result shows a stable change.

[0135] Please refer to Figure 10 , Figure 10This is a schematic diagram illustrating the phase correction process in an embodiment of this application. The orange line represents the amplitude demodulation signal, i.e., the first amplitude demodulation result. The blue line represents the unwound phase demodulation signal, i.e., the second phase demodulation result. Two obvious distortions can be seen in the second phase demodulation result. The purple portion of the amplitude demodulation signal is used to replace the first distortion in the second phase demodulation result, and the cyan portion of the amplitude demodulation signal is used to replace the second distortion in the second phase demodulation result.

[0136] Please refer to Figure 11 , Figure 11 This is a schematic diagram of the frequency spectral density of the second-phase demodulation result and the third-phase demodulation result. (See diagram for example.) Figure 11 As shown, blue represents the frequency spectral density of the second-phase demodulated signal, and yellow represents the frequency spectral density of the third-phase demodulated signal, which is also the corrected frequency spectral density of the second-phase demodulated signal. After adopting the distributed optical fiber data processing method provided in this application, the signal-to-noise ratio is improved by nearly 20 dB. The distributed optical fiber data processing method provided in this application can simply and quickly correct the phase demodulated signal, preserving the characteristics of the original signal to the greatest extent possible while significantly improving the signal quality.

[0137] Please refer to Figure 12 , Figure 12 This is a schematic diagram of the structure of a distributed optical fiber data processing system 5 according to one embodiment of this application. Figure 12 As shown, the distributed optical fiber data processing system 5 includes a memory, a processor, and a program stored in the memory and capable of running on the processor. When the processor executes the program, it implements the distributed optical fiber data processing method 1.

[0138] exist Figure 12 In the illustrated embodiments, the distributed optical fiber data processing system 5 may include a computer-readable storage medium 52, which may store a program that can be invoked by a processor 51, and may include a non-volatile storage medium. In some embodiments, the distributed optical fiber data processing system may include memory 53 and an interface 54. In some embodiments, the distributed optical fiber data processing system may also include other hardware depending on the actual application.

[0139] This application, in another aspect, provides a computer-readable storage medium on which a program is stored, which, when executed, implements the distributed optical fiber data processing method 1. In some embodiments, it may take the form of a computer program product implemented on one or more computer-readable storage media 52 (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing program code. The computer-readable storage medium 52 includes permanent and non-permanent, removable and non-removable media, and information storage can be implemented by any method or technology. The information may be computer-readable instructions, data structures, program modules, or other data. Examples of computer-readable storage media 52 include, but are not limited to: phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, read-only optical disc read-only memory (CD-ROM), digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium, which can be used to store information that can be accessed by a computing device.

[0140] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the application disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0141] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A method for processing distributed optical fiber sensor data, characterized in that, The processing method includes: Amplitude demodulation and phase demodulation are performed on the fiber optic sensing data at each spatial location to obtain the first amplitude demodulation result and the first phase demodulation result at each spatial location. The first phase demodulation results at each spatial location are de-wound to obtain the second phase demodulation results at each spatial location; Based on the second phase demodulation results at each spatial location, determine whether an erroneous unwinding has occurred at each spatial location; If an erroneous unwinding occurs at a certain spatial location, the second phase demodulation result at that spatial location is corrected using the first amplitude demodulation result at that spatial location.

2. The method for processing distributed optical fiber sensor data according to claim 1, characterized in that, If an erroneous unwinding occurs at a certain spatial location, the second phase demodulation result at that spatial location is corrected using the first amplitude demodulation result at that spatial location, including: Determine the spatial location of the unwinding error, the first amplitude demodulation result at the spatial location of the unwinding error, and the second phase demodulation result at the spatial location of the unwinding error; wherein, the spatial location of the unwinding error is the spatial location where the erroneous unwinding occurs; The first amplitude demodulation result and the second phase demodulation result at the unwinding error spatial location are filtered to obtain the second amplitude demodulation result and the third phase demodulation result; Determine the displacement difference between the second amplitude demodulation result and the third phase demodulation result, and align the first amplitude demodulation result, the second amplitude demodulation result, the second phase demodulation result, and the third phase demodulation result according to the displacement difference; Based on the amplitude of the second amplitude demodulation result and the amplitude of the third phase demodulation result, the amplitude of the first amplitude demodulation result is adjusted to obtain the third amplitude demodulation result; Determine the unwinding error time region in the second phase demodulation result at the spatial location of the unwinding error; The segment corresponding to the unwinding error time region in the third amplitude demodulation result is used to replace the segment corresponding to the unwinding error time region in the second phase demodulation result to obtain the corrected unwinding phase demodulation result.

3. The method for processing distributed optical fiber sensing data according to claim 1, characterized in that, After unwinding the first phase demodulation results at each spatial location to obtain the second phase demodulation results at each spatial location, the processing method further includes: Detrending is performed on the first amplitude demodulation result and the second phase demodulation result at each spatial location.

4. The method for processing distributed optical fiber sensor data according to claim 1, characterized in that, The determination of whether erroneous unwinding has occurred at each spatial location based on the second phase demodulation results at each spatial location includes: Based on the second phase demodulation results at each spatial location, calculate the frequency spectral density of the low-frequency band and the frequency spectral density of the high-frequency band at each spatial location. If the difference between the frequency spectral density of the low-frequency band and the frequency spectral density of the high-frequency band at a certain spatial location is greater than the limit for the difference in frequency spectral density, it is determined that an erroneous unwinding has occurred at that spatial location.

5. The method for processing distributed optical fiber sensing data according to claim 2, characterized in that, The filtering of the first amplitude demodulation result and the second phase demodulation result at the unwinding error spatial location to obtain the second amplitude demodulation result and the third phase demodulation result includes: The first amplitude demodulation result and the second phase demodulation result at the unwinding error spatial location are filtered using a bandpass filter, and interference data is removed to obtain the second amplitude demodulation result and the third phase demodulation result. The center frequency of the bandpass filter ranges from 10Hz to Fs / 4, where Fs is the repetition frequency of the light source in the distributed optical fiber sensing system that acquires the distributed optical fiber sensing data.

6. The method for processing distributed optical fiber sensing data according to claim 5, characterized in that, The deletion of interfering data includes: Delete the first drift interference segment at the beginning of the first amplitude demodulation result after filtering at the spatial location of the unwinding error; Delete the second drift interference segment at the beginning of the filtered second phase demodulation result at the unwinding error spatial location.

7. The method for processing distributed optical fiber sensing data according to claim 2, characterized in that, Determining the shift difference between the second amplitude demodulation result and the third phase demodulation result includes: Peak finding is performed on the second amplitude demodulation result and the third phase demodulation result; wherein the interval between peaks is in the range of Fs / 2f0 to Fs / f0, where Fs is the repetition frequency of the light source in the distributed optical fiber sensing system that acquires the distributed optical fiber sensing data, and f0 is the center frequency of the bandpass filter; Obtain the time positions of multiple peaks in the second amplitude demodulation result and the time positions of multiple peaks in the third phase demodulation result; The average of the differences between the time positions of multiple peaks in the second amplitude demodulation result and the time positions of multiple peaks in the corresponding third phase demodulation result is calculated as the displacement difference.

8. The method for processing distributed optical fiber sensing data according to claim 2, characterized in that, The step of adjusting the amplitude of the first amplitude demodulation result based on the amplitude of the second amplitude demodulation result and the amplitude of the third phase demodulation result to obtain the third amplitude demodulation result includes: Based on the standard deviation of the amplitude of the second amplitude demodulation result and the standard deviation of the amplitude of the third phase demodulation result, the amplitude of the first amplitude demodulation result is adjusted to obtain the third amplitude demodulation result; the standard deviation of the third amplitude demodulation result is consistent with the standard deviation of the amplitude of the third phase demodulation result.

9. The method for processing distributed optical fiber sensing data according to claim 8, characterized in that, The step of adjusting the amplitude of the first amplitude demodulation result based on the standard deviation of the amplitude of the second amplitude demodulation result and the standard deviation of the amplitude of the third phase demodulation result includes: Determine the first standard deviation of the amplitude of the second amplitude demodulation result; Determine the temporal location of the unwinding error in the second phase demodulation result at the spatial location of the unwinding error; The third phase demodulation result is divided into multiple time intervals based on the unwinding error time position; Determine the standard deviation of the amplitude of the third phase demodulation result in each time interval, and take the mean of the standard deviations of multiple amplitudes as the second standard deviation of the third phase demodulation result; The amplitude of the first amplitude demodulation result is scaled up to the ratio of the first standard deviation to the second standard deviation.

10. The method for processing distributed optical fiber sensing data according to claim 2, characterized in that, The step of replacing the segment corresponding to the unwinding error time region in the second phase demodulation result with the segment corresponding to the unwinding error time region in the third amplitude demodulation result to obtain the corrected unwinding phase demodulation result includes: Obtain the first amplitude difference between the second amplitude demodulation result and the third phase demodulation result at the beginning position of the unwinding error time region; Obtain the second amplitude difference between the second amplitude demodulation result and the third phase demodulation result at the end of the unwinding error time region; Extract the segment of the third amplitude demodulation result in the unwinding error time region and replace the segment of the second phase demodulation result in the unwinding error time region by shifting the first amplitude difference vertically; The second phase demodulation result is shifted vertically by the second amplitude difference in the segment after the unwinding error time region, so as to align with the vertically shifted third amplitude demodulation result in the segment of the unwinding error time region.

11. The method for processing distributed optical fiber sensing data according to claim 1, characterized in that, The processing method further includes: The distributed optical fiber sensing data is acquired through an acquisition device, and the amplitude demodulation and phase demodulation are performed on the distributed optical fiber sensing data acquired by the acquisition device.

12. The method for processing distributed optical fiber sensing data according to claim 1, characterized in that, The processing method further includes: The distributed optical fiber sensing data is acquired by a main acquisition device and an auxiliary acquisition device, respectively. The distributed optical fiber sensing data acquired by the main acquisition device is subjected to phase demodulation, and the distributed optical fiber sensing data acquired by the auxiliary acquisition device is subjected to amplitude demodulation.

13. A distributed optical fiber sensing data processing system, characterized in that: The invention includes a memory, a processor, and a computer program stored in the memory, characterized in that the processor executes the computer program to implement a method for processing distributed optical fiber sensing data as described in any one of claims 1-12.

14. A storage medium, characterized in that, The storage medium stores a program, which, when executed, implements the method for processing distributed optical fiber sensing data as described in any one of claims 1-12.

Images