A signal processing method, system, device and storage medium of a BOTDR

Abstract

The application relates to the field of optical fiber sensing, and relates to a BOTDR signal processing method, a system, a device and a storage medium. The method comprises the following steps: acquiring Brillouin frequency domain data of an optical fiber position point; performing Brillouin frequency shift detection processing on the Brillouin frequency domain data to obtain a fitting data amount of the Brillouin frequency domain data; performing main peak seeking processing on the Brillouin frequency domain data to obtain a selected point region; in the selected point region of the Brillouin frequency domain data, a corresponding fitting data amount is selected as fitting data of the Brillouin frequency domain data; the fitting data is fitted based on a fitting target function to obtain a fitting curve, and a frequency value corresponding to a wave peak of the fitting curve is obtained, and the frequency value is taken as a Brillouin frequency shift; and the temperature and / or stress change of the optical fiber position point is obtained according to the Brillouin frequency shift. The method can realize accurate Lorentz curve fitting based on a BOTDR signal, and improves the efficiency and accuracy of fitting.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical fiber sensing, and more particularly, to a BOTDR signal processing method, system, device and storage medium. BACKGROUND

[0002] At present, optical fibers show important application value in the health monitoring of large buildings such as bridges and tunnels and the state monitoring of super-long distance pipelines including power systems, communication systems and oil and gas pipelines due to their high sensitivity to temperature and stress changes. In these monitoring scenarios, based on the Brillouin Optical Time Domain Reflectometer (BOTDR) technology, the Brillouin frequency shift caused by temperature or stress changes is obtained by fitting the Lorentz curve of the Brillouin scattering signal, which is a key technical means. In the prior art, common fitting methods include linear least squares fitting by approximating discrete data with a Lorentz curve to minimize deviation, Levenberg-Marquardt algorithm fitting by iteratively operating to reduce the objective function to obtain the optimal solution, and special machine learning methods such as support vector machines (SVM), neural networks and cross-correlation methods. However, the above-mentioned fitting methods generally have the practical problems of large amount of calculation and slow speed, and when the Brillouin scattering spectrum appears as a double-peak spectrum, the fitting effect is poor, which to some extent limits their application efficiency and accuracy in actual monitoring.

[0003] Therefore, it is necessary to make necessary improvements to the signal processing method of BOTDR. SUMMARY

[0004] The present application provides a BOTDR signal processing method, system, device and storage medium for realizing accurate fitting of the Lorentz curve based on the BOTDR signal and improving the efficiency and accuracy of fitting.

[0005] According to a first aspect of the present application, a BOTDR signal processing method is provided, the method comprising:

[0006] obtaining a set of Brillouin frequency domain data for each optical fiber position point;

[0007] performing Brillouin frequency shift detection processing on each set of Brillouin frequency domain data to obtain a fitting data amount corresponding to each set of Brillouin frequency domain data;

[0008] performing main peak finding processing on each set of Brillouin frequency domain data to obtain a selected point region;

[0009] in the selected point region corresponding to each set of Brillouin frequency domain data, selecting a fitting data corresponding to each set of Brillouin frequency domain data according to the corresponding fitting data amount.

[0010] fitting the fitting data corresponding to each group of the Brillouin frequency domain data based on the fitting target function to obtain a fitting curve, and obtaining a frequency value corresponding to a wave peak of the fitting curve as the Brillouin frequency shift;

[0011] According to the Brillouin frequency shift, the temperature and / or stress change of the corresponding optical fiber position point is obtained.

[0012] It can be understood that by accurately obtaining the Brillouin frequency domain data of each optical fiber position point, a solid data foundation is laid for subsequent analysis; the Brillouin frequency shift detection processing and the main peak seeking processing on the Brillouin frequency domain data can effectively filter out the key data area where the Brillouin frequency shift occurs, thereby improving the accuracy and efficiency of data processing; in the selected area, the corresponding fitting data amount is selected as the fitting data, which can deeply fit the key data and simply fit the data that has not relatively occurred the Brillouin frequency shift, thereby ensuring the key processing of the key data, improving the processing precision, reducing other redundant unnecessary processing, and improving the processing efficiency; by using the fitting target function, the Brillouin frequency domain data is accurately fitted, and the Brillouin frequency shift is accurately obtained. Finally, based on the accurate determination of the Brillouin frequency shift, the real-time and accurate monitoring of the temperature and / or stress change of the corresponding optical fiber position point is realized, which not only improves the processing precision of the Brillouin scattering signal, but also improves the precision and efficiency of the fitting processing, thereby providing strong support for the application in the field of optical fiber sensing.

[0013] Optionally, the Brillouin frequency shift detection processing on each group of the Brillouin frequency domain data comprises:

[0014] obtaining the first and last position points of the optical fiber;

[0015] taking the optical fiber position points between the first and last position points of the optical fiber as detection points, adding the Brillouin frequency domain data corresponding to each detection point to the Brillouin frequency domain data of the adjacent previous optical fiber position point to obtain a plurality of added amplitudes;

[0016] obtaining a maximum added amplitude corresponding to each group of the Brillouin frequency domain data according to the plurality of added amplitudes corresponding to each group of the Brillouin frequency domain data;

[0017] determining whether the maximum added amplitude is less than or equal to a preset first amplitude threshold value, if yes, it is determined that the corresponding Brillouin frequency domain data has occurred the Brillouin frequency shift; if not, it is determined that the corresponding Brillouin frequency domain data has not occurred the Brillouin frequency shift.

[0018] It can be understood that the fiber position points between the head and tail position points of the optical fiber are set as detection points, and the Brillouin frequency domain data of each detection point is added with the data of the adjacent previous fiber position point to obtain an added amplitude value. By comparing whether the maximum value in the added amplitude value is less than or equal to a first amplitude threshold value, it can be accurately judged whether the Brillouin frequency domain data has Brillouin frequency shift. Through the fine detection between the head and tail position points of the optical fiber and the accumulation analysis of the Brillouin frequency domain data, efficient identification of the Brillouin frequency shift is realized, which not only improves the efficiency of data processing, but also enhances the accuracy of Brillouin frequency shift detection, and provides a reliable data basis for subsequent temperature and stress change monitoring based on the Brillouin frequency shift.

[0019] Optionally, the obtaining of the fitting data quantity corresponding to each group of Brillouin frequency domain data comprises:

[0020] If the Brillouin frequency domain data has Brillouin frequency shift, the fiber position points corresponding to the Brillouin frequency domain data and the fiber position points before and after the preset number of fiber position points are taken as frequency shift influence points, and a preset first fitting point number is selected as the fitting data quantity of the corresponding Brillouin frequency domain data for each frequency shift influence point;

[0021] A preset second fitting point number is selected as the fitting data quantity of the corresponding Brillouin frequency domain data for other fiber position points except the frequency shift influence points;

[0022] The first fitting point number is greater than the second fitting point number.

[0023] It can be understood that when the Brillouin frequency shift of the Brillouin frequency domain data is detected, the fiber position points and the fiber position points before and after the preset number of fiber position points are marked as frequency shift influence points, and more fitting point numbers are set for these frequency shift influence points to capture the Brillouin frequency shift characteristics more finely, so as to ensure the accuracy of the fitting result. For the fiber position points not affected by the Brillouin frequency shift, a smaller number of fitting points is used to ensure the processing efficiency while meeting the basic fitting requirements. This differentiated fitting data quantity setting method not only ensures the high-precision processing of the key area, but also avoids unnecessary calculation burden in the global range, thereby optimizing the processing flow of the Brillouin scattering signal and improving the monitoring accuracy and response speed of the temperature and stress change.

[0024] Optionally, the main peak seeking processing of each group of Brillouin frequency domain data to obtain a selected point region comprises:

[0025] The number of wave peaks of the Brillouin frequency domain data is obtained;

[0026] If the number of wave peaks of the Brillouin frequency domain data is one, the wave peak is taken as the main peak of the Brillouin frequency domain data;

[0027] If the number of wave peaks of the Brillouin frequency domain data is multiple, peak point amplitudes of the multiple wave peaks are obtained;

[0028] A maximum peak point amplitude is obtained according to the peak point amplitudes, and a wave peak corresponding to the maximum peak point amplitude is taken as a main peak of the Brillouin frequency domain data;

[0029] A selected point region is obtained from the corresponding Brillouin frequency domain data according to a preset second amplitude threshold and the main peak.

[0030] It can be understood that, by performing main peak seeking processing on the Brillouin frequency domain data, the main peak of the Brillouin frequency domain data is accurately identified, the corresponding wave peak is directly selected as the main peak for single-wave-peak data, and the main peak is determined by comparing the peak point amplitudes for multiple-wave-peak data, so that the accuracy of main peak selection for multiple-wave-peak data is ensured. In combination with the second amplitude threshold for screening the selected point region, noise interference and interference of non-main peak data in the multiple-wave-peak data are effectively excluded, and the accuracy and reliability of data processing are improved, thereby laying a solid foundation for accurate calculation of Brillouin frequency shift and temperature / stress monitoring.

[0031] Optionally, the obtaining of the selected point region from the corresponding Brillouin frequency domain data according to the preset second amplitude threshold and the main peak comprises:

[0032] A plurality of frequency offset values are obtained forward and backward with the main peak as the center based on the corresponding Brillouin frequency domain data, and an amplitude corresponding to the frequency offset value is greater than or equal to the second amplitude threshold;

[0033] A minimum frequency offset value and a maximum frequency offset value in the plurality of frequency offset values are obtained;

[0034] The minimum frequency offset value is taken as a lower limit of frequency of the selected point region, and the maximum frequency offset value is taken as an upper limit of frequency of the selected point region;

[0035] The corresponding Brillouin frequency domain data is divided according to the lower limit of frequency and the upper limit of frequency to obtain the selected point region.

[0036] It can be understood that, by combining the preset second amplitude threshold and the main peak positioning, the selected point region of the Brillouin frequency domain data is accurately determined; the frequency offset values corresponding to the amplitudes greater than or equal to the second amplitude threshold are obtained forward and backward with the main peak as the center, and the minimum frequency offset value and the maximum frequency offset value are determined as the upper and lower limits of frequency, so that the data segment containing the main peak and the adjacent high-amplitude region is effectively screened. This method not only improves the accuracy of the selected point region and reduces noise interference, but also ensures the complete retention of key information, thereby providing a high-quality data basis for subsequent accurate calculation of Brillouin frequency shift and reliable monitoring of temperature / stress change, and significantly improving the overall performance and monitoring accuracy of the optical fiber sensing system.

[0037] Optionally, the step of fitting the fitted data corresponding to each group of Brillouin frequency domain data based on the fitting objective function to obtain the fitted curve includes:

[0038] The fitting objective function Represented as:

[0039]

[0040] in, The fitting objective function The frequency offset variable, The fitting objective function Parameters;

[0041] Based on the fitted data, determine Initial values ​​of the parameters:

[0042]

[0043]

[0044]

[0045] in, The maximum frequency offset value in the fitted data. The minimum frequency offset value in the fitted data. The maximum amplitude value in the fitted data. The minimum amplitude in the fitted data;

[0046] Based on the fitted objective function The fitted data is subjected to iterative fitting processing to obtain... Medium parameters The optimal solution, according to the above Obtain the fitted curve.

[0047] Understandably, this involves constructing a fitting objective function based on the Lorenz curve model. By initializing parameters using the fitted data, efficient and accurate fitting of Brillouin frequency domain data was achieved. Using frequency offset as a variable, combined with Four key parameters comprehensively capture the characteristics of Brillouin frequency domain data. During initialization, these parameters are rationally set using data extrema. The initial value is used to ensure the accuracy of the fitting starting point. This is achieved by fitting the objective function. Through iterative optimization, the optimal solutions for the four parameters are precisely obtained, thus yielding the fitted curve. This method not only improves fitting efficiency and accuracy but also effectively reduces noise interference, providing reliable data support for the accurate monitoring of temperature and stress changes in fiber optic sensing.

[0048] Optionally, the obtaining a set of Brillouin frequency domain data of each optical fiber position point comprises:

[0049] obtaining a set of Brillouin time domain data of each optical fiber position point, performing fast Fourier transform and cumulative average processing on each set of Brillouin time domain data to obtain corresponding frequency domain data;

[0050] performing log smoothing processing on each set of frequency domain data;

[0051] performing normalization processing on each set of frequency domain data after the smoothing processing to obtain each set of Brillouin frequency domain data.

[0052] It can be understood that the Brillouin time domain data of each optical fiber position point is converted into frequency domain data through fast Fourier transform, and the signal-to-noise ratio of the data is enhanced through cumulative average processing, laying a solid foundation for subsequent analysis; the log smoothing processing on the frequency domain data effectively suppresses sharp fluctuations and noise in the data, making the data characteristics more clear and identifiable; through normalization processing, the frequency domain data of different optical fiber position points are unified to the same order of magnitude, eliminating the influence of amplitude difference on subsequent analysis, and ensuring the consistency and comparability of the data. The above processing not only improves the accuracy and reliability of the Brillouin frequency domain data, but also provides high-quality data support for accurate detection of Brillouin frequency shift and precise monitoring of temperature / stress change.

[0053] According to a second aspect of the present application, a signal processing system of a BOTDR is provided, the system comprising:

[0054] an acquisition curve module for acquiring a set of Brillouin frequency domain data of each optical fiber position point;

[0055] a Brillouin frequency shift detection module for performing Brillouin frequency shift detection processing on each set of Brillouin frequency domain data to obtain a fitting data amount corresponding to each set of Brillouin frequency domain data;

[0056] a selected point region acquisition module for performing main peak searching processing on each set of Brillouin frequency domain data to obtain a selected point region;

[0057] a fitting data acquisition module for selecting, in the selected point region corresponding to each set of Brillouin frequency domain data, fitting data corresponding to each set of Brillouin frequency domain data according to the corresponding fitting data amount;

[0058] a fitting module for fitting the fitting data corresponding to each set of Brillouin frequency domain data based on a fitting target function to obtain a fitting curve, and obtaining a frequency value corresponding to a wave peak of the fitting curve as the Brillouin frequency shift;

[0059] a change obtaining module, configured to obtain temperature and / or stress change of a corresponding optical fiber position point according to the Brillouin frequency shift.

[0060] According to a third aspect of the present application, an electronic device is provided, comprising:

[0061] a memory, configured to store one or more computer programs;

[0062] a processor, when the one or more computer programs are executed by the processor, implements the signal processing method of the BOTDR according to the first aspect.

[0063] According to a fourth aspect of the present application, a computer readable storage medium is provided, which stores computer instructions for causing a processor to implement the signal processing method of the BOTDR according to the first aspect when executed.

[0064] According to any one of the above aspects, the embodiments of the present application provide a signal processing method, system, device and storage medium of the BOTDR, a set of Brillouin frequency domain data of each optical fiber position point is obtained; Brillouin frequency shift detection processing is performed on each set of Brillouin frequency domain data to obtain a fitting data amount corresponding to each set of Brillouin frequency domain data; main peak seeking processing is performed on each set of Brillouin frequency domain data to obtain a selected point region; in the selected point region corresponding to each set of Brillouin frequency domain data, fitting data corresponding to each set of Brillouin frequency domain data is selected according to the corresponding fitting data amount; fitting is performed on the fitting data corresponding to each set of Brillouin frequency domain data based on a fitting target function to obtain a fitting curve, and a frequency value corresponding to a wave peak of the fitting curve is obtained, which is taken as the Brillouin frequency shift; and temperature and / or stress change of a corresponding optical fiber position point is obtained according to the Brillouin frequency shift. The above method has the following benefits:

[0065] ·accurately and efficiently obtaining the Brillouin frequency shift: the present application distinguishes from the method of using convolution processing in the prior art to find the Brillouin frequency shift, avoids the auxiliary processing process and large consumption of computing resources caused by the method of using convolution processing, and instead obtains the first and last position points of the optical fiber, adds the Brillouin frequency domain data of the detection points between the first and last position points of the optical fiber to the Brillouin frequency domain data of the adjacent previous optical fiber position point, obtains a plurality of added amplitudes, and accurately judges whether the Brillouin frequency domain data has a frequency shift by analyzing the added amplitudes. This step not only improves the accuracy of frequency shift detection, but also simplifies the processing process and saves computing resources, improves the efficiency of obtaining the optical fiber position point of the Brillouin frequency shift, provides a reliable basis for subsequent data processing, and ensures the accuracy of the monitoring result.

[0066] The application can effectively locate key data in the Brillouin frequency domain data by acquiring the main peak and the corresponding selected point region, and improve the probability of obtaining accurate Brillouin frequency shift subsequently. Meanwhile, limiting the selected point in the data range where the main peak is located can correspond to compatible processing of multi-peak spectrum, and reduce the misjudgment and poor fitting effect of traditional multi-peak spectrum processing.

[0067] The application cooperates with the main peak seeking processing to construct a unified fitting target function, which is different from the traditional fitting data for single-peak data and multi-peak data for fitting, and can avoid the complex process and redundant processing process of using different fitting target functions for fitting in different positions of the same optical fiber. Meanwhile, it can be understood that the accurate selection of the initial value of the fitting target function can greatly improve the fitting effect of the function. The application uses a unified fitting target function to obtain accurate parameter initial values by using fitting data, which has good fitting effect for single-peak data and multi-peak data, so that the Brillouin frequency shift corresponding to the position of the optical fiber can be accurately obtained, and the accurate detection of temperature and / or stress change can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0068] In order to more clearly illustrate the technical solutions in the embodiments of the application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0069] Figure 1 A flowchart of a signal processing method of a BOTDR provided for the embodiment.

[0070] Figure 2 A flowchart of Brillouin frequency domain data acquisition and processing provided for the embodiment.

[0071] Figure 3 A flowchart of a Brillouin frequency shift detection processing method provided for the embodiment.

[0072] Figure 4 A flowchart of a main peak seeking processing method provided for the embodiment.

[0073] Figure 5 A flowchart of a selected point region division method provided for the embodiment.

[0074] Figure 6 A schematic diagram of fitting a Lorentz curve for single-peak data of Brillouin frequency domain data provided for the embodiment.

[0075] Figure 7 A schematic diagram of fitting a Lorentz curve for double-peak data of Brillouin frequency domain data provided for the embodiment.

[0076] Figure 8 A functional module schematic diagram of a signal processing system of a BOTDR provided for the embodiment.

[0077] Figure 9 A structural schematic diagram of an electronic device provided for the embodiment. DETAILED DESCRIPTION

[0078] The drawings of the present application are only used for illustrative description, and cannot be understood as limitation to the present application. In order to better illustrate the following embodiments, some components in the drawings will be omitted, enlarged or reduced, and do not represent the actual product size; it is understandable for those skilled in the art that some well-known structures and their descriptions in the drawings can be omitted.

[0079] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of protection of the present application.

[0080] It should be noted that the terms "first", "second" and the like in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily limit to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0081] As a highly sensitive sensing element, optical fiber has unique physical properties that enable it to accurately perceive and respond to changes in temperature and stress. This feature provides strong technical support for many monitoring fields, such as structural health monitoring, geological disaster warning, and power system safety. In these applications, Brillouin frequency shift, as a key parameter in optical fiber sensing technology, can be used as one of the important means of monitoring. Brillouin frequency shift can reflect the temperature or stress changes of the environment in which the optical fiber is located. Moreover, due to the good linear relationship between Brillouin frequency shift and temperature or stress change, the temperature or stress change at the corresponding optical fiber position point can be quickly and accurately inferred by measuring the Brillouin frequency shift, thereby achieving real-time and accurate monitoring of the monitored object.

[0082] However, in actual monitoring process, due to the limitation of the collection accuracy of Brillouin optical time domain reflectometer (BOTDR), we can only obtain a large number of discrete data at a certain optical fiber position point. These discrete data may not be continuous and may not fully represent the true state of the optical fiber. Moreover, when Brillouin frequency shift occurs at a certain optical fiber position point, the Brillouin scattering signal will exhibit instability, resulting in large errors in the collected data. Research has found that the Brillouin scattering data in the optical fiber can be approximated to a Lorentz curve. By fitting the discrete Brillouin scattering data into a continuous Lorentz curve, the Brillouin frequency shift can be more accurately extracted, thereby effectively reducing the error and improving the monitoring accuracy.

[0083] The fitting method in the prior art, such as linear least squares fitting, is a commonly used curve approximation method that seeks the best fitting curve by minimizing the deviation. However, it has large computational load, slow calculation speed, and poor fitting effect when dealing with complex data. Levenberg-Marquardt algorithm, as an iterative optimization method, can reduce the objective function to some extent and obtain the optimal solution, but it also faces the problem of low computational efficiency. In addition, for special cases such as double-peak spectrum data, the processing effect of these traditional fitting methods is often poor, which is difficult to meet the needs of practical applications.

[0084] Therefore, it is necessary to make necessary improvements to the signal processing of BOTDR.

[0085] The embodiment provides a technical solution that can solve the above problems. The specific embodiments of the application will be described in detail below with reference to the accompanying drawings.

[0086] As shown in Figure 1 The embodiment provides a signal processing method of BOTDR, which can be divided into the following steps:

[0087] S100, acquiring a set of Brillouin frequency domain data of each fiber position point;

[0088] Specifically, as shown in the figure, the step of acquiring a set of Brillouin frequency domain data of each fiber position point can include the following steps: Figure 2

[0089] S110, acquiring a set of Brillouin time domain data of each fiber position point, and performing fast Fourier transform and cumulative average processing on each set of Brillouin time domain data to obtain corresponding frequency domain data;

[0090] It can be understood that the Brillouin time domain data in the optical fiber is acquired by a Brillouin optical time domain reflectometer (BOTDR). The working principle of the Brillouin optical time domain reflectometer is based on optical time domain reflection technology, which acquires information by transmitting light pulses into the optical fiber and receiving backscattered light.

[0091] It can be understood that the Brillouin optical time domain reflectometer (BOTDR) has long distance monitoring capability, and the monitoring distance can reach tens of kilometers, which is suitable for long distance and large range monitoring requirements, and can reduce the number and cost of monitoring points. In this embodiment, the Brillouin time domain data of multiple fiber position points in an optical fiber is acquired, and each fiber position point corresponds to a set of Brillouin time domain data. Similarly, after performing fast Fourier transform and cumulative average processing on each set of Brillouin time domain data of each fiber position point, a set of Brillouin frequency domain data of each fiber position point can also be obtained.

[0092] In this embodiment, the acquired Brillouin time domain data needs to be processed by fast Fourier transform (FFT) and cumulative average processing to obtain corresponding frequency domain data. Because the Brillouin frequency shift, which has a good linear relationship with the temperature or stress change in the optical fiber, is a frequency domain parameter itself, converting the Brillouin time domain data into frequency domain data and then processing it can more conveniently and quickly obtain the corresponding Brillouin frequency shift. Cumulative average processing of the Brillouin time domain data can effectively reduce the noise in the data and enhance the signal stability, and provide high-quality data support for subsequent analysis, especially when the converted frequency domain data appears double peaks or multiple peaks, the double peak or multiple peak transition position can present a slow moving upward process, so that the subsequent fitting work can be more smoothly and accurately completed, and the fitting accuracy is improved.

[0093] ​It can be understood that, in the actual monitoring process, due to the limitation of the acquisition accuracy of the Brillouin optical time domain reflectometer (BOTDR), only a large number of discrete data of a certain fiber position point can be obtained, which cannot completely represent the real state of the optical fiber. When Brillouin frequency shift occurs at a certain fiber position point, the Brillouin scattering signal will appear unstable, resulting in a large error in the collected data. It is found that the Brillouin scattering data in the optical fiber can be approximated to a Lorentz curve in shape, so that the Brillouin frequency shift can be extracted more accurately by fitting the discrete Brillouin scattering data into a continuous Lorentz curve, thereby effectively reducing the error and improving the monitoring accuracy.

[0094] In a preferred embodiment, a preset uniform number of points can be used as the total number of discrete points obtained at each fiber position point. Specifically, the total number of discrete points is determined by the frequency and bandwidth of the analog-to-digital converter (ADC) sampling, and is a fixed value. Preferably, in this embodiment, the total number of discrete points can be 128 points.

[0095] It can be understood that the obtained Brillouin frequency domain data can be a three-dimensional data, each set of Brillouin frequency domain data corresponding to a fiber position point, specifically the position information of the fiber position point; the Brillouin frequency domain data of the fiber position point is a two-dimensional discrete point graph, which takes frequency as the first coordinate and Brillouin intensity as the second coordinate, reflecting the Brillouin intensity value corresponding to each frequency offset value.

[0096] S120, performing log smoothing processing on each set of frequency domain data;

[0097] In this embodiment, the log smoothing processing of the frequency domain data can effectively suppress high-frequency noise, enhance signal feature contrast, improve weak signal sensitivity, and provide high-quality data for subsequent normalization and fitting processing.

[0098] S130, performing normalization processing on each set of frequency domain data that has completed the smoothing processing to obtain each set of Brillouin frequency domain data.

[0099] Specifically, for each set of frequency domain data that has completed the smoothing processing, normalization processing is performed according to the following formula:

[0100]

[0101] wherein, is the current amplitude of a discrete data in the frequency domain data, is the normalized amplitude of the discrete data, is the maximum amplitude in the frequency domain data, the minimum amplitude value in the frequency domain data, an absolute value operation is performed.

[0102] It can be understood that the normalization of the frequency domain data can eliminate the amplitude difference, enhance the characteristics of the main peak, provide a unified reference for subsequent analysis, reduce the complexity of calculation, improve the sensitivity of weak signals, and help improve the accuracy of Brillouin frequency shift detection.

[0103] S200, performing Brillouin frequency shift detection processing on each group of the Brillouin frequency domain data to obtain a fitting data quantity corresponding to each group of the Brillouin frequency domain data;

[0104] In this embodiment, the fiber position point where the Brillouin frequency shift occurs and the nearby other fiber position points affected by the Brillouin frequency shift are preliminarily obtained, the key data where the Brillouin frequency shift occurs is preliminarily located, and the key data is focused on fitting, and the data not affected by the Brillouin frequency shift is simply fitted, which not only ensures the accuracy of the key data fitting, but also avoids in-depth processing of unnecessary data, thereby improving the efficiency of the fitting processing.

[0105] Specifically, as shown in the figure, Figure 3 the Brillouin frequency shift detection processing on each group of the Brillouin frequency domain data can include the following steps:

[0106] S210, obtaining fiber head and tail position points;

[0107] In this embodiment, in the Brillouin frequency shift detection processing, the Brillouin frequency domain data corresponding to the front and rear fiber position points are compared to obtain the fiber position point of the Brillouin frequency shift. In order to facilitate the operation and avoid the redundant process of comparison, the fiber head and tail position points are obtained, and the fiber head and tail position points are marked by default and not compared.

[0108] S220, taking the fiber position points between the fiber head and tail position points as detection points, adding the Brillouin frequency domain data corresponding to each detection point to the Brillouin frequency domain data of the adjacent previous fiber position point to obtain a plurality of added amplitudes;

[0109] It can be understood that in the fiber sensing, the frequency coordinates of the Brillouin frequency domain data have consistency, that is, the Brillouin frequency domain data obtained at different fiber position points on the same fiber are located in the same frequency band range. This characteristic shows that the Brillouin scattering signal of the fiber remains stable in the frequency dimension and is independent of the position of the fiber, so that the related analysis of obtaining the Brillouin frequency shift is mainly concentrated on the amplitude of the Brillouin frequency domain data. Therefore, in this embodiment, the Brillouin frequency domain data corresponding to each detection point is added to the Brillouin frequency domain data of the adjacent previous fiber position point, and a plurality of doubled frequency offset values are obtained in the frequency.

[0110] It can be understood that the Brillouin frequency shift BFS refers to the change amount of the frequency of the Brillouin scattered light in the optical fiber relative to the frequency of the incident light. In actual application, if the Brillouin frequency shift occurs at the optical fiber position point, the first peak value of the corresponding Brillouin frequency domain data relative to the second peak value of the Brillouin frequency domain data of the adjacent previous optical fiber position point will move in frequency, specifically, the frequency offset value corresponding to the second peak value will decrease or increase compared with the frequency offset value corresponding to the first peak value, and therefore it is called Brillouin frequency shift. Generally, the Brillouin frequency shift occurs only when the temperature or stress change occurs at the optical cable position point, otherwise, the Brillouin frequency shift will not occur.

[0111] Therefore, if there is no temperature or stress change at the optical fiber position point, the Brillouin frequency shift will not occur in the Brillouin frequency domain data corresponding to the optical fiber position point, that is, the peak position of the Brillouin frequency domain data of the optical fiber position point will not change; after the Brillouin frequency shift occurs, the peak position of the Brillouin frequency domain data will move forward and backward in the frequency coordinate.

[0112] It can be understood that the traditional Brillouin frequency shift detection and processing needs to be convoluted to determine the correlation coefficient in order to obtain the optical fiber position point where the Brillouin frequency shift occurs. However, the convolution processing usually consumes a lot of computing resources, and the processing efficiency is not high. In the embodiment, the normalized Brillouin frequency domain data follows the uniform reference amplitude, and the frequency band position and size are unchanged, and the Brillouin frequency domain data corresponding to the front and rear optical fiber position points are added to obtain a plurality of added amplitudes, and the added amplitudes are used to judge whether the detection point has the Brillouin frequency shift. The method of the present application is simple and convenient, and can save a large amount of computing resources and improve the efficiency of Brillouin frequency shift detection.

[0113] S230, obtaining a maximum added amplitude corresponding to each group of Brillouin frequency domain data according to a plurality of added amplitudes corresponding to the Brillouin frequency domain data;

[0114] In the embodiment, the added amplitude can reflect the movement of the peak value of the Brillouin frequency domain data. It can be understood that if the peak value of the Brillouin frequency domain data of the optical fiber position point does not change, the frequency offset value corresponding to the peak value is consistent with the frequency offset value corresponding to the peak value of the Brillouin frequency domain data of the adjacent previous optical fiber position point. Therefore, when adding, the amplitudes corresponding to the same frequency offset value are added, so that the peak value of the Brillouin frequency domain data of the optical fiber position point is added to the peak value of the Brillouin frequency domain data of the adjacent previous optical fiber position point, and the maximum added amplitude of the obtained added amplitude is ensured to be the sum of the two peak values.

[0115] If the peak value of the Brillouin frequency domain data of the fiber position point changes, the frequency offset value corresponding to the peak value is inconsistent with the frequency offset value corresponding to the peak value of the Brillouin frequency domain data of the adjacent previous fiber position point. Therefore, when the peak value is added to the amplitude value corresponding to the same frequency offset value in the Brillouin frequency domain data of the adjacent previous fiber position point, the obtained added amplitude value is usually smaller than the added amplitude value corresponding to the addition of the two peak values. Similarly, the peak value of the Brillouin frequency domain data of the adjacent previous fiber position point is also added to the amplitude value (non-peak value) corresponding to the same frequency offset value in the Brillouin frequency domain data of the fiber position point, so the obtained added amplitude value is usually smaller than the added amplitude value corresponding to the addition of the two peak values.

[0116] By using the maximum added amplitude value as the analysis data, the added amplitude value affected by the peak value can be found with the maximum probability, so that the movement of the peak value can be found.

[0117] For example, it is assumed that the peak value of the Brillouin frequency domain data of the fiber position point is represented as , and the peak value of the Brillouin frequency domain data of the adjacent previous fiber position point can be represented as . Because each set of Brillouin frequency domain data is normalized, the peak value of each Brillouin frequency domain data is equal, so .

[0118] If the Brillouin frequency shift does not occur at the fiber position point, it can be understood that because the peak value does not move, so ; therefore, at the frequency offset value , the obtained added amplitude value is 2 . It can be understood that 2 is the maximum added amplitude value among all added amplitude values, because no other added amplitude value corresponding to the frequency offset value is greater than the value obtained by adding the two peak values.

[0119] If the Brillouin frequency shift occurs at the fiber position point, , and in the Brillouin frequency domain data of the adjacent previous fiber position point, the frequency offset value is , the amplitude value corresponding to the Brillouin frequency domain data of the adjacent previous fiber position point is , and usually , so the added amplitude value obtained by adding is . Similarly, the frequency offset value is , the amplitude value corresponding to the Brillouin frequency domain data of the fiber position point is , and usually , so the added amplitude value obtained by adding is . Therefore, the maximum added amplitude value of all obtained added amplitude values is usually smaller than twice the amplitude value 2 .

[0120] S240, judging whether the maximum added amplitude is less than or equal to a preset first amplitude threshold value, if yes, determining that the corresponding Brillouin frequency domain data has Brillouin frequency shift; if no, determining that the corresponding Brillouin frequency domain data has no Brillouin frequency shift.

[0121] In the embodiment, the first amplitude threshold value can be preset to be compared with the maximum added amplitude, if less than or equal to the first amplitude threshold value, it is proved that the maximum added amplitude is not obtained by adding two peak values, it is proved that the peak value of the Brillouin frequency domain data of the fiber position point has moved, the Brillouin frequency domain data has Brillouin frequency shift. If no, it is determined that the corresponding Brillouin frequency domain data has no Brillouin frequency shift. In theory, the first amplitude threshold value is preset to be twice the amplitude, but in order to allow some noise and collection errors to occur, the first amplitude threshold value can be preset to be close to twice the peak value, and a small amount of error deviation is allowed. Exemplarily, because each set of Brillouin frequency domain data is normalized, the peak value of each set of Brillouin frequency domain data can be 1, that is, twice the peak value can be 2, and the first amplitude threshold value can be preset to be 1.97, and the first amplitude threshold value can be appropriately adjusted according to actual conditions.

[0122] Specifically, the fitting data amount corresponding to each set of Brillouin frequency domain data is obtained, including:

[0123] If the Brillouin frequency domain data has Brillouin frequency shift, the fiber position point corresponding to the Brillouin frequency domain data and a preset number of fiber position points before and after the fiber position point are taken as frequency shift influence points, and a preset first fitting point number is selected as the fitting data amount of the corresponding Brillouin frequency domain data for each frequency shift influence point;

[0124] A preset second fitting point number is selected as the fitting data amount of the corresponding Brillouin frequency domain data for other fiber position points except the frequency shift influence points;

[0125] The first fitting point number is greater than the second fitting point number.

[0126] In the embodiment, if the Brillouin frequency domain data has Brillouin frequency shift, a large amount of noise will occur when the Brillouin optical time domain reflectometer (BOTDR) is collected, and the collected signal is unstable. Because Brillouin frequency shift occurs in a certain fiber position point, the fiber position points before and after the fiber position point can be affected, so the fiber position point corresponding to the Brillouin frequency domain data and a preset number of fiber position points before and after the fiber position point are taken as frequency shift influence points. Preferably, the preset number can be set to 4, and the preset number can be appropriately adjusted according to actual conditions.

[0127] It can be understood that the frequency shift affected point can reflect that the frequency shift affected point can have temperature and / or stress changes, so it is necessary to use more first fitting points corresponding to the frequency shift affected point as the fitting data amount of the Brillouin frequency domain data, which can minimize the influence of individual error data on the fitting effect and reduce the fitting error caused by unstable data. For other fiber position points other than the frequency shift affected point, it can be basically determined that no Brillouin frequency shift occurs, so only a small number of second fitting points are needed as the fitting data amount, which can save computing resources and speed up the processing speed.

[0128] It can be understood that, in order to simplify the complexity of the fitting process and reduce the consumption of computing resources, the first fitting point number and the second fitting point number are generally set to be less than the total number of discrete points of the Brillouin frequency domain data, so that all discrete points are not needed as data basis when doing fitting processing, and the efficiency of fitting is improved.

[0129] S300, main peak finding processing is performed on each group of Brillouin frequency domain data to obtain a selected point region;

[0130] In the embodiment, in order to simplify the complexity of the fitting and reduce the fitting point number required during the fitting processing, reduce the resource occupied by the point number matrix operation, speed up the running speed of the fitting processing, and avoid the influence of noise and double-peak data transition position on the fitting, main peak finding processing is needed for the Brillouin frequency domain data. The main peak needs to occur Brillouin shift, and the selected point region is obtained in the front and back range of the main peak position, so that the fitting data selected in the selected point region contains the data of the Brillouin frequency shift, accurately locates the occurrence position of the key data, and improves the accuracy of the fitting processing.

[0131] Specifically, as shown in Figure 4 The main peak finding processing on each group of Brillouin frequency domain data to obtain a selected point region can include the following steps:

[0132] S310, the number of wave peaks of the Brillouin frequency domain data is obtained;

[0133] S320, if the number of wave peaks of the Brillouin frequency domain data is one, the wave peak is taken as the main peak of the Brillouin frequency domain data; if the number of wave peaks of the Brillouin frequency domain data is multiple, the peak point amplitude of multiple wave peaks is obtained; the maximum peak point amplitude is obtained according to a plurality of peak point amplitudes, and the wave peak corresponding to the maximum peak point amplitude is taken as the main peak of the Brillouin frequency domain data;

[0134] In the embodiment, if the number of wave peaks of the Brillouin frequency domain data is one, it means that the Brillouin frequency domain data is single-peak data, and the wave peak is directly taken as the main peak of the Brillouin frequency domain data.

[0135] In this embodiment, if there are multiple peaks in the Brillouin frequency domain data, it indicates that the Brillouin frequency domain data is multi-peak data. It is necessary to obtain the peak corresponding to the maximum peak amplitude among the multiple peaks as the main peak to prevent other peaks caused by noise or peaks caused by the transition position of the optical fiber due to temperature or stress changes from affecting the fitting process.

[0136] S330. Based on the preset second amplitude threshold and the main peak, obtain the selected area from the corresponding Brillouin frequency domain data.

[0137] Specifically, such as Figure 5 As shown, the step of obtaining the selected area from the corresponding Brillouin frequency domain data based on the preset second amplitude threshold and the main peak may include the following steps:

[0138] S331. Based on the corresponding Brillouin frequency domain data, with the main peak as the center, obtain several frequency offset values ​​forward and backward, wherein the amplitude corresponding to the frequency offset value is greater than or equal to the second amplitude threshold.

[0139] Understandably, Brillouin shift typically occurs near the peak of the Brillouin frequency domain data. Therefore, it is necessary to obtain several frequency offset values ​​greater than or equal to the second amplitude threshold, centered on the main peak, both forward and backward. Setting the second amplitude threshold ensures that the obtained frequency offset values ​​are limited to a preset range of the main peak, preventing the selected point area from being too large or too small, and ensuring that the fitted data selected from the reselected point area does not differ too much, thereby improving the efficiency and accuracy of selecting the fitted data. Preferably, the second amplitude threshold can be set to 0.8, which ensures that the selected point area roughly includes discrete data of about 10 discrete points. The second amplitude threshold can be adjusted appropriately according to the actual situation.

[0140] S332. Obtain the minimum and maximum frequency offset values ​​among the plurality of frequency offset values;

[0141] S333. The minimum frequency deviation value is used as the lower limit of the frequency of the selected area, and the maximum frequency deviation value is used as the upper limit of the frequency of the selected area.

[0142] S334. Divide the corresponding Brillouin frequency domain data according to the lower frequency limit and the upper frequency limit to obtain the selected point region.

[0143] Specifically, assuming the lower frequency limit is The upper limit of frequency is And in a straight line and straight line The area enclosed by the peak is used as the selection area to ensure that several discrete points, including the main peak, are selected as fitting data.

[0144] S400, in the selected point region corresponding to each group of the Brillouin frequency domain data, selecting fitting data corresponding to each group of the Brillouin frequency domain data according to the corresponding fitting data amount;

[0145] In the embodiment, the fitting data amount to be selected for each fiber position point is obtained through step S200, and the selected point region is obtained through step S300. Therefore, for the Brillouin frequency shift data corresponding to each fiber position point, the corresponding fitting data amount in the selected point region can be selected as the fitting data corresponding to each group of the Brillouin frequency domain data, thereby providing a data basis for subsequent fitting of each group of the Brillouin frequency domain data.

[0146] S500, fitting the fitting data corresponding to each group of the Brillouin frequency domain data based on a fitting target function to obtain a fitting curve, obtaining a frequency value corresponding to a wave peak of the fitting curve, and taking the frequency value as the Brillouin frequency shift;

[0147] It can be understood that the Brillouin frequency domain data corresponding to each fiber position point is approximately a Lorentz curve, and the Brillouin frequency shift can be accurately obtained by fitting the Lorentz curve for each group of the Brillouin frequency domain data. Preferably, the Lorentz curve model is defined as:

[0148]

[0149] wherein, is a frequency offset value, is a frequency offset value is the corresponding scattered light intensity, is a peak intensity in the scattering data, is a full width at half maximum of the scattering data, represents the Brillouin frequency shift.

[0150] In order to facilitate fitting processing, in the embodiment, the above Lorentz curve model is modified as:

[0151]

[0152] wherein, is a frequency offset variable of the modified model is a parameter of the modified model ; the initial value of the modified model represents the Brillouin frequency shift, the initial value of the modified model represents the Brillouin frequency shift, the initial value of the modified model

[0153] Understandably, in this embodiment, the relevant fitting processing needs to be completed in the Matrix Laboratory (MATLAB), and the variation needs to be converted into a MATLAB-readable formula, i.e., the fitting objective function of this embodiment. The fitting objective function of this embodiment is constructed based on the above variation.

[0154] Specifically, the step of fitting the fitted data corresponding to each group of Brillouin frequency domain data based on the fitting objective function to obtain the fitted curve includes:

[0155] The fitting objective function Represented as:

[0156]

[0157] in, The fitting objective function The frequency offset variable, The fitting objective function Parameters;

[0158] Based on the fitted data, determine Initial values ​​of the parameters:

[0159]

[0160]

[0161]

[0162] in, The maximum frequency offset value in the fitted data. The minimum frequency offset value in the fitted data. The maximum amplitude value in the fitted data. The minimum amplitude in the fitted data;

[0163] Based on the fitted objective function The fitted data is subjected to iterative fitting processing to obtain... Medium parameters The optimal solution, according to the above Obtain the fitted curve.

[0164] In the embodiment, according to boundary data of the fitting data, such as maximum frequency offset value, minimum frequency offset value, maximum amplitude value and minimum amplitude value, the initial value of the parameter of the fitting target function is preliminarily obtained, the fitting target function is preliminarily shaped, and then the several discrete points in the fitting data are fitted based on the shaped fitting target function. It can be understood that, in the fitting process, the fitting target function needs to be converted into a least square expression processable by Matlab, the distance between the fitting data and the fitting target function is reduced and balanced through the fitting iteration process based on the fitting data, and the parameters are continuously adjusted , so as to obtain the fitting target function with good fitting effect.

[0165] It can be understood that, after the optimal solution of the fitting target function is obtained, the corresponding Lorentz curve needs to be drawn and displayed, the fitting target function needs to be converted into the Lorentz curve variant in the embodiment, and the Brillouin frequency domain data is drawn by Matlab. The variant is , wherein the parameters respectively correspond to

[0166]

[0167]

[0168]

[0169] , the optimal solution of the fitting target function is

[0170] It can be understood that, after the fitting curve is obtained, the frequency value corresponding to the wave peak of the fitting curve needs to be obtained, and the frequency value is taken as the Brillouin frequency shift. Specifically, the optimal solution of the fitting target function is also equivalent to , the optimal solution of the fitting target function can directly represent the frequency value corresponding to the wave peak of the fitting curve, so can be directly taken as the Brillouin frequency shift.

[0171] As shown in Figure 6 , it is a schematic diagram of fitting a Lorentz curve for single-peak data of Brillouin frequency domain data, and as shown in Figure 7 , it is a schematic diagram of fitting a Lorentz curve for double-peak data of Brillouin frequency domain data.

[0172] S600, according to the Brillouin frequency shift, the temperature and / or stress change of the corresponding optical fiber position point is obtained.

[0173] ​​Specifically, since there is a good linear relationship between the Brillouin frequency shift and the temperature and / or stress change, the temperature and / or stress change at the corresponding fiber position point can be obtained according to the obtained Brillouin frequency shift. Preferably, the change of the temperature or stress can be obtained by the following formula:

[0174]

[0175] wherein, represents the propagation speed of acoustic phonons in the fiber material, represents the frequency of the incident light, represents the material property, represents the temperature, represents that the refractive index depends on the material property and the temperature, Young's modulus, represents the Poisson's ratio, represents the core density.

[0176] As Figure 8 shown, the embodiment of the present application further provides a signal processing system of the BOTDR. Optionally, the system comprises:

[0177] a curve obtaining module 711, a Brillouin frequency shift detection module 712, a selected point region obtaining module 713, a fitting data obtaining module 714, a fitting module 715, and a change obtaining module 716, wherein:

[0178] the curve obtaining module 711 is configured to obtain a set of Brillouin frequency domain data of each fiber position point;

[0179] In the embodiment, the curve obtaining module 711 can be configured to perform the step S100 shown in Figure 1 the specific description of the curve obtaining module 711 can refer to the description of the step S100.

[0180] the Brillouin frequency shift detection module 712 is configured to perform Brillouin frequency shift detection processing on each set of the Brillouin frequency domain data to obtain a fitting data amount corresponding to each set of the Brillouin frequency domain data;

[0181] In the embodiment, the Brillouin frequency shift detection module 712 can be configured to perform the step S200 shown in Figure 1 the specific description of the Brillouin frequency shift detection module 712 can refer to the description of the step S200.

[0182] the selected point region obtaining module 713 is configured to perform main peak peak searching processing on each set of the Brillouin frequency domain data to obtain a selected point region;

[0183] In the embodiment, the selected point region obtaining module 713 can be configured to perform the step S300 shown in Figure 1The step S300 is shown, and the specific description of the point selection area acquisition module 713 can refer to the description of the step S300.

[0184] The fitting data acquisition module 714 is configured to select fitting data corresponding to each group of the Brillouin frequency domain data according to the corresponding fitting data amount in the point selection area corresponding to each group of the Brillouin frequency domain data.

[0185] In this embodiment, the fitting data acquisition module 714 can be configured to perform Figure 1 The step S400 is shown, and the specific description of the fitting data acquisition module 714 can refer to the description of the step S400.

[0186] The fitting module 715 is configured to fit the fitting data corresponding to each group of the Brillouin frequency domain data based on a fitting target function to obtain a fitting curve, and acquire a frequency value corresponding to a wave peak of the fitting curve as the Brillouin frequency shift.

[0187] In this embodiment, the fitting module 715 can be configured to perform Figure 1 The step S500 is shown, and the specific description of the fitting module 715 can refer to the description of the step S500.

[0188] The change acquisition module 716 is configured to acquire temperature and / or stress change of a corresponding optical fiber position point according to the Brillouin frequency shift.

[0189] In this embodiment, the change acquisition module 716 can be configured to perform Figure 1 The step S600 is shown, and the specific description of the change acquisition module 716 can refer to the description of the step S600.

[0190] The embodiments of the present application further provide an electronic device, and the structure thereof is shown as Figure 9 The electronic device includes a memory 811, a processor 812, a communication module 813, and an input / output interface 814, and the memory 811, the processor 812, the communication module 813, and the input / output interface 814 can be connected and communicated through a bus 815.

[0191] The memory 811 is configured to store one or more computer programs and transmit the codes of the computer programs to the processor 812; when the one or more computer programs are executed by the processor 812, the signal processing method of the BOTDR in the embodiments of the present application is implemented.

[0192] Optionally, the electronic device can be connected to a network through the communication module 813 to communicate with other devices such as terminals or servers through the network to realize the interaction of data. The electronic device can be various forms of digital computers, such as desktop computers, servers, workstations, mainframe computers or other types of computers. The electronic device can also be various forms of mobile terminals, such as smartphones, tablet computers, wearable devices (such as helmets, glasses, watches, etc.) and other similar mobile terminals.

[0193] Optionally, the electronic device can connect the required input / output devices such as keyboards, display devices, etc. through the input / output interface 814. The electronic device itself can have a display device and can also be externally connected to other display devices through the input / output interface 814. Optionally, storage devices such as hard disks, etc. can also be connected through the input / output interface 814, so that the data in the electronic device can be stored in the storage device or the data in the storage device can be read, and the data in the storage device can also be stored in the memory 811. It can be understood that the input / output interface 814 can be a wired interface or a wireless interface. According to different actual application scenarios, the devices connected to the input / output interface 814 can be a component of the electronic device or an external device connected to the electronic device when needed.

[0194] Optionally, the memory 811 can be a volatile memory and / or a non-volatile memory. The volatile memory can be a random access memory, etc. The non-volatile memory can be a read-only memory, a programmable read-only memory, an erasable programmable read-only memory, an electrically erasable programmable read-only memory or a flash memory, etc.

[0195] Optionally, the computer program stored in the memory 811 can be divided into one or more modules, which are stored in the memory 811 and executed by the processor 812 to complete the method provided by the embodiment. The one or more modules can be a series of computer program instruction segments capable of completing a specific function, which are used to describe the execution process of the computer program in the electronic device.

[0196] Optionally, the processor 812 can be various general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of the processor 812 include, but are not limited to, a central processing unit, a graphics processing unit, a digital signal processor, various special-purpose artificial intelligence computing chips, various processors running machine learning model algorithms, and can also be any appropriate controller, microcontroller, processor, etc. The processor 812 executes various methods and processes of the embodiments, for example, a signal processing method of a BOTDR of the embodiments of the present application.

[0197] Optionally, the bus 815 can include a path for transmitting information. According to different functions, the bus 815 can be divided into an address bus, a data bus, a control bus, etc.

[0198] In an optional implementation, the embodiments of the present application also provide a computer storage medium having a computer program stored thereon, and the computer program enables a computer to execute the method of the method embodiments when executed by the computer. Part or all of the computer program can be loaded and / or installed on the memory 811 of the electronic device. When the computer program is executed by the processor 812, one or more steps of the signal processing method of a BOTDR of the embodiments of the present application can be executed.

[0199] Optionally, the computer-readable storage medium can be a random access memory, a read-only memory, a programmable read-only memory, an erasable programmable read-only memory, an electrically erasable programmable read-only memory, etc.

[0200] Obviously, the above-described embodiments of the present application are only examples for clearly illustrating the technical solutions of the present application, and are not intended to limit the specific embodiments of the present application. Any modification, equivalent replacement, and improvement made within the spirit and principle of the claims of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A signal processing method for BOTDR, characterized in that, The method includes: Obtain a set of Brillouin frequency domain data for each fiber location; Brillouin frequency shift detection processing is performed on each group of Brillouin frequency domain data to obtain the amount of fitted data corresponding to each group of Brillouin frequency domain data. The Brillouin frequency shift detection processing for each group of Brillouin frequency domain data includes: obtaining the beginning and end positions of the optical fibers; using the optical fiber positions between the beginning and end positions as detection points, adding the Brillouin frequency domain data corresponding to each detection point to the Brillouin frequency domain data of the adjacent preceding optical fiber position point to obtain several summed amplitudes; obtaining the corresponding maximum summed amplitude based on the several summed amplitudes corresponding to each group of Brillouin frequency domain data; determining whether the maximum summed amplitude is less than or equal to a preset first amplitude threshold; if so, determining that the corresponding Brillouin frequency domain data has undergone Brillouin frequency shift; otherwise, determining that the corresponding Brillouin frequency domain data has not undergone Brillouin frequency shift. For each group of Brillouin frequency domain data, perform peak finding processing to obtain the selected area; In the selected point region corresponding to each group of Brillouin frequency domain data, the fitting data corresponding to each group of Brillouin frequency domain data is selected according to the corresponding amount of fitting data; The fitting curve is obtained by fitting the fitting data corresponding to each group of Brillouin frequency domain data based on the fitting objective function, and the frequency value corresponding to the peak of the fitting curve is obtained. The frequency value is used as the Brillouin frequency shift. The temperature and / or stress changes at the corresponding fiber location points are obtained based on the Brillouin frequency shift.

2. The method according to claim 1, characterized in that, The step of obtaining the amount of fitted data corresponding to each group of Brillouin frequency domain data includes: If the Brillouin frequency domain data undergoes a Brillouin frequency shift, the fiber location point corresponding to the Brillouin frequency domain data and the preset number of fiber location points before and after it are taken as frequency shift influence points, and a preset first number of fitting points is selected for each frequency shift influence point as the corresponding Brillouin frequency domain data fitting data quantity. For fiber location points other than the frequency shift-affected points, a preset second number of fitting points is selected as the corresponding Brillouin frequency domain data fitting data volume; The first number of fitted points is greater than the second number of fitted points.

3. The method according to claim 1, characterized in that, The step of performing peak-finding processing on each group of Brillouin frequency domain data to obtain the selected point region includes: Obtain the number of peaks in the Brillouin frequency domain data; If the number of peaks in the Brillouin frequency domain data is one, then the peak is taken as the main peak of the Brillouin frequency domain data. If there are multiple peaks in the Brillouin frequency domain data, then the peak amplitudes of the multiple peaks are obtained; The maximum peak amplitude is obtained based on several peak amplitude values, and the peak corresponding to the maximum peak amplitude is taken as the main peak of the Brillouin frequency domain data. The selected area is obtained from the corresponding Brillouin frequency domain data based on the preset second amplitude threshold and the main peak.

4. The method according to claim 3, characterized in that, The step of obtaining the selected region from the corresponding Brillouin frequency domain data based on the preset second amplitude threshold and the main peak includes: Based on the corresponding Brillouin frequency domain data, several frequency offset values ​​are obtained forward and backward with the main peak as the center, and the amplitude corresponding to the frequency offset value is greater than or equal to the second amplitude threshold. Obtain the minimum and maximum frequency offset values ​​among the aforementioned frequency offset values; The minimum frequency offset value is used as the lower frequency limit of the selected area, and the maximum frequency offset value is used as the upper frequency limit of the selected area. The selected point region is obtained by dividing the corresponding Brillouin frequency domain data according to the lower frequency limit and the upper frequency limit.

5. The method according to any one of claims 1 to 4, characterized in that, The process of fitting the fitted data corresponding to each group of Brillouin frequency domain data based on the fitting objective function to obtain the fitted curve includes: The fitting objective function Represented as: in, The fitting objective function The frequency offset variable, The fitting objective function Parameters; Based on the fitted data, determine Initial values ​​of the parameters: in, The maximum frequency offset value in the fitted data. The minimum frequency offset value in the fitted data. The maximum amplitude value in the fitted data. The minimum amplitude in the fitted data; Based on the fitted objective function The fitted data is subjected to iterative fitting processing to obtain... Medium parameters The optimal solution, according to the above Obtain the fitted curve.

6. The method according to any one of claims 1 to 4, characterized in that, The acquisition of a set of Brillouin frequency domain data for each fiber location point includes: A set of Brillouin time-domain data for each fiber location is obtained, and the corresponding frequency-domain data is obtained by performing fast Fourier transform and cumulative averaging on each set of Brillouin time-domain data. For each group of frequency domain data, perform a smoothing process by taking the logarithm (logarithm). Normalize the frequency domain data of each group that has undergone the smoothing process to obtain the Brillouin frequency domain data of each group.

7. A signal processing system for a BOTDR, characterized in that, The system includes: The curve acquisition module is used to acquire a set of Brillouin frequency domain data for each fiber location point; The Brillouin frequency shift detection module is used to perform Brillouin frequency shift detection processing on each group of Brillouin frequency domain data to obtain the amount of fitted data corresponding to each group of Brillouin frequency domain data. The Brillouin frequency shift detection processing on each group of Brillouin frequency domain data includes: obtaining the beginning and end positions of the optical fiber; using the optical fiber position points between the beginning and end positions as detection points, adding the Brillouin frequency domain data corresponding to each detection point to the Brillouin frequency domain data of the adjacent preceding optical fiber position point to obtain several summed amplitudes; obtaining the corresponding maximum summed amplitude based on the several summed amplitudes corresponding to each group of Brillouin frequency domain data; determining whether the maximum summed amplitude is less than or equal to a preset first amplitude threshold; if so, determining that the corresponding Brillouin frequency domain data has undergone Brillouin frequency shift; otherwise, determining that the corresponding Brillouin frequency domain data has not undergone Brillouin frequency shift. The point selection region acquisition module is used to perform peak finding processing on each group of Brillouin frequency domain data to obtain the point selection region; The fitting data acquisition module is used to select the fitting data corresponding to each group of Brillouin frequency domain data in the selected point region corresponding to each group of Brillouin frequency domain data according to the corresponding fitting data quantity. The fitting module is used to fit the fitting data corresponding to each group of Brillouin frequency domain data based on the fitting objective function to obtain a fitting curve, and to obtain the frequency value corresponding to the peak of the fitting curve, and to use the frequency value as the Brillouin frequency shift. The change acquisition module is used to acquire the temperature and / or stress changes at the corresponding fiber location points based on the Brillouin frequency shift.

8. The system according to claim 7, characterized in that, The point selection area acquisition module is also used for: Obtain the number of peaks in the Brillouin frequency domain data; If the number of peaks in the Brillouin frequency domain data is one, then the peak is taken as the main peak of the Brillouin frequency domain data; if the number of peaks in the Brillouin frequency domain data is multiple, then the peak amplitudes of multiple peaks are obtained; the maximum peak amplitude is obtained based on the multiple peak amplitudes, and the peak corresponding to the maximum peak amplitude is taken as the main peak of the Brillouin frequency domain data. The selected area is obtained from the corresponding Brillouin frequency domain data based on the preset second amplitude threshold and the main peak.

9. An electronic device, characterized in that, include: Memory, used to store one or more computer programs; A processor, when the one or more computer programs are executed by the processor, implements a signal processing method for a BOTDR as described in any one of claims 1-6.

10. A computer-readable storage medium storing computer instructions for causing a processor to execute and implement a signal processing method for a BOTDR as described in any one of claims 1-6.

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