Distributed optical fiber data common-mode noise elimination method and system and storage medium

Abstract

The invention provides a distributed optical fiber data common-mode noise elimination method and system and a storage medium, and belongs to the field of optical fiber sensing technology application. The method comprises the following steps: inputting original DAS data; extracting a noise standard channel; performing noise matching filtering; performing noise median filtering; and outputting the de-noised data. According to the method, the original DAS data is sequentially subjected to noise matching filtering and noise median filtering, so that the signal-to-noise ratio of the DAS data can be improved.

Description

Technical Field

[0001] The present invention belongs to the field of optical fiber sensing technology applications, and in particular relates to a distributed optical fiber data common mode noise elimination method, system and storage medium. Background Art

[0002] As an emerging transformative technology, distributed optical fiber sensing (DAS) has developed rapidly in the fields of oil and gas exploration and development, engineering monitoring, etc., but there are still some problems that need to be solved urgently.

[0003] During DAS data collection, affected by the collection equipment itself and external environmental factors, the laser emitted by the light source will generate common mode noise, and the demodulated data will generate different degrees of common mode noise. The characteristic of this noise is that the same amplitude of noise will appear simultaneously on different channels in the record.

[0004] Currently, this kind of common mode noise is generally avoided by reducing internal and external factors during acquisition. However, in actual acquisition, environmental factors are not ideal and cannot be completely avoided. Summary of the invention

[0005] The purpose of the present invention is to solve the difficulties existing in the above-mentioned prior art and to provide a distributed optical fiber data common mode noise elimination method, system and storage medium, which solves the problem that when the existing distributed optical fiber sensor DAS is collecting data, the demodulated data will produce common mode noise to varying degrees due to the influence of the collection equipment itself and external environmental factors.

[0006] One of the purposes of the present invention is to provide a distributed optical fiber data common mode noise elimination method.

[0007] A second object of the present invention is to provide a distributed optical fiber data common mode noise elimination system.

[0008] A third object of the present invention is to provide a computer readable storage medium.

[0009] A fourth object of the present invention is to provide a computer device.

[0010] The present invention is achieved through the following technical solutions:

[0011] A first aspect of the present invention provides a method for eliminating common mode noise of distributed optical fiber data, wherein original DAS data is subjected to noise matching filtering and noise median filtering in sequence to obtain denoised data.

[0012] A further improvement of the present invention is:

[0013] The method comprises the following steps:

[0014] Input raw DAS data;

[0015] Extract the noise standard track;

[0016] Noise matched filtering;

[0017] Noise median filtering;

[0018] Output denoised data.

[0019] A further improvement of the present invention is:

[0020] The original DAS data is the original data collected by the distributed optical fiber sensing DAS, including channel data and sampling time.

[0021] A further improvement of the present invention is:

[0022] The specific operation of extracting the noise standard channel includes:

[0023] All channel data in the original DAS data are superimposed and the superimposed data are used as the noise standard channel.

[0024] A further improvement of the present invention is:

[0025] The noise matched filtering specifically includes:

[0026] Match filtering is performed on the noise standard channel and the original DAS data channel by channel;

[0027] The valid signal data after matched filtering is retained.

[0028] A further improvement of the present invention is:

[0029] The noise median filtering specifically includes the following operations:

[0030] (1) For the data output by the matched filter in the third step, at a sampling time, a channel is selected in the channel direction, and a time window is selected with the sample point corresponding to the channel as the midpoint, and the median value of the sample points in the time window is obtained, and the median value of the sample points is subtracted from the midpoint value to obtain the output value at the midpoint position;

[0031] (2) At the same sampling time as step (1), perform a channel cycle and repeat step (1) to obtain the output value at the corresponding midpoint position on each channel;

[0032] (3) After calculating the results of all channels at a sampling time in step (2), the sampling time loop is performed again, and steps (1) and (2) are repeated to obtain the output values ​​of all sampling times and channel directions.

[0033] A further improvement of the present invention is:

[0034] The output denoised data is specifically:

[0035] The data after noise median filtering is output as a two-dimensional array according to the time sequence and channel number, which is the denoised data.

[0036] A third aspect of the present invention provides a distributed optical fiber data common mode noise elimination system, comprising:

[0037] An input unit, used to input raw DAS data;

[0038] An extraction unit, connected to the input unit, for extracting a noise standard channel;

[0039] A matched filtering unit, connected to the extraction unit, for noise matched filtering;

[0040] A median filter unit, connected to the matched filter unit, for performing noise median filtering;

[0041] The output unit is connected to the median filter unit and is used to output the denoised data.

[0042] According to a third aspect of the present invention, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores at least one computer-executable program, and when the at least one program is executed by the computer, the computer executes the steps in the distributed optical fiber data common-mode noise elimination method as described above.

[0043] A fourth aspect of the present invention provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the distributed optical fiber data common mode noise elimination method as described above.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] The present invention proposes a method and system for eliminating common mode noise of DAS data. The original DAS data is subjected to noise matching filtering and noise median filtering in sequence, so as to improve the signal-to-noise ratio of the DAS data. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 is a flow chart of a method for eliminating common-mode noise of distributed optical fiber data in an embodiment of the present invention;

[0047] Figure 2 It is the DAS raw data;

[0048] Figure 3 is the matched filtering result;

[0049] Figure 4It is the final denoising result of the present invention. DETAILED DESCRIPTION

[0050] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0051] The present invention provides a method for eliminating common mode noise of DAS data. The original DAS data is subjected to noise matching filtering and noise median filtering in sequence to obtain denoised data.

[0052] The embodiments of the method of the present invention are as follows:

[0053] [Example 1]

[0054] like Figure 1 As shown, the following steps are included:

[0055] Step 1: Input the original DAS data;

[0056] The original DAS data is the original data collected by the distributed optical fiber sensing DAS, including channel data and sampling time.

[0057] The second step is to extract the noise standard track;

[0058] All channel data in the original DAS data are superimposed, and the superimposed data is used as the noise standard channel;

[0059] The third step is noise matched filtering;

[0060] Specific operations include:

[0061] Matching filtering is performed on the noise standard channel and the original DAS data channel by channel. The matched filtering method can adopt the existing technical method, which will not be described in detail here;

[0062] The valid signal data after matched filtering is retained.

[0063] After the noise is matched and filtered, most of the lateral noise events are eliminated, but there is still a small amount of residue, such as Figure 3 shown.

[0064] Step 4: Noise median filtering;

[0065] Specific operations include:

[0066] (1) For the data output by the matched filter in the third step, at a sampling time, take a channel in the channel direction, take a time window with the sample point corresponding to the channel as the midpoint (that is, at the sampling time, take a time window on different channels with the taken channel as the center), obtain the median of the sample points in the time window (median is a basic concept in mathematical statistics, which is to sort the data according to the size of the value and take the value of the middle data), subtract the median of the sample points from the midpoint value, and use the output value at the midpoint position;

[0067] The size of the time window can be determined by the test results. Specifically, different time window sizes can be used to process the entire process of the present invention respectively, and the time window corresponding to the result with the best effect is selected according to the processing effect.

[0068] (2) At the same sampling time as step (1), perform a channel cycle and repeat step (1) to obtain the output value at the corresponding midpoint position on each channel;

[0069] (3) After calculating the results of all channels at a sampling time in step (2), the sampling time loop is performed again, and steps (1) and (2) are repeated to obtain the output values ​​of all sampling times and channel directions.

[0070] After median filtering, Figure 3 The residual noise in the image is further eliminated, and the profile basically only has valid signals, such as Figure 4 shown.

[0071] Step 5: Output the denoised data.

[0072] The data after noise median filtering is output as a two-dimensional array according to the time sequence and channel number, which is the denoised data.

[0073] like Figure 2 The figure shows the actual data of a vertical seismic profile collected by distributed acquisition. The horizontal axis is the channel and the vertical axis is time. Figure 2 It can be seen that there is a strong horizontal phase axis in the channel direction, which is the common mode noise.

[0074] Figure 3 Yes Figure 2 The result after the original data is matched filtered shows that the common mode noise on the filtered data is greatly reduced, but there is still a little residual.

[0075] Figure 4 is Figure 3 The final output result after further median filtering shows that the signal-to-noise ratio of the output result is further improved.

[0076] The present invention also provides a distributed optical fiber data common mode noise elimination system, and the embodiments of the distributed optical fiber data common mode noise elimination system are as follows:

[0077] [Example 2]

[0078] The distributed optical fiber data common mode noise elimination system comprises:

[0079] An input unit, used for inputting raw DAS data; the raw DAS data is the raw data collected by the distributed optical fiber sensing DAS, including channel data and sampling time;

[0080] An extraction unit, connected to the input unit, is used to extract a noise standard channel; all channel data in the original DAS data are superimposed, and the superimposed data is used as the noise standard channel;

[0081] A matched filtering unit, connected to the extraction unit, for noise matched filtering; the matched filtering method may adopt the existing technical method;

[0082] A median filter unit is connected to the matched filter unit and is used for noise median filtering; the specific operations include:

[0083] (1) For the data output by the matched filter in the third step, at a sampling time, take a channel in the channel direction, take a time window with the sample point corresponding to the channel as the midpoint (that is, at the sampling time, take a time window on different channels with the taken channel as the center), obtain the median of the sample points in the time window (median is a basic concept in mathematical statistics, which is to sort the data according to the size of the value and take the value of the middle data), subtract the median of the sample points from the midpoint value, and use the output value at the midpoint position;

[0084] The size of the time window can be determined by the test results. Specifically, different time window sizes can be used to process the entire process of the present invention respectively, and the time window corresponding to the result with the best effect is selected according to the processing effect.

[0085] (2) At the same sampling time as step (1), perform a channel cycle and repeat step (1) to obtain the output value at the corresponding midpoint position on each channel;

[0086] (3) After calculating the results of all channels at a sampling time in step (2), the sampling time loop is performed again, and steps (1) and (2) are repeated to obtain the output values ​​of all sampling times and channel directions;

[0087] The output unit is connected to the median filtering unit and is used to output the denoised data. Specifically, the data after the noise median filtering is output as a two-dimensional array according to the time sequence and the channel sequence number, that is, the denoised data.

[0088] The present invention also provides a computer-readable medium, and an embodiment of the computer-readable medium is as follows:

[0089] [Example 3]

[0090] The computer-readable storage medium stores at least one computer-executable program, and when the at least one program is executed by the computer, the computer executes the steps in the distributed optical fiber data common mode noise elimination method as described above.

[0091] The specific steps include:

[0092] Step 1: Input the original DAS data;

[0093] The original DAS data is the original data collected by the distributed optical fiber sensing DAS, including channel data and sampling time;

[0094] The second step is to extract the noise standard track;

[0095] All channel data in the original DAS data are superimposed, and the superimposed data is used as the noise standard channel;

[0096] The third step is noise matching filtering. The specific operations include:

[0097] Matching filtering is performed on the noise standard channel and the original DAS data channel by channel, and the matched filtering method can adopt the existing technology;

[0098] The valid signal data after matched filtering is retained.

[0099] The fourth step is noise median filtering. The specific operations include:

[0100] (1) For the data output by the matched filter in the third step, at a sampling time, take a channel in the channel direction, take a time window with the sample point corresponding to the channel as the midpoint (that is, at the sampling time, take a time window on different channels with the taken channel as the center), obtain the median of the sample points in the time window (median is a basic concept in mathematical statistics, which is to sort the data according to the size of the value and take the value of the middle data), subtract the median of the sample points from the midpoint value, and use the output value at the midpoint position;

[0101] The size of the time window can be determined by the test results. Specifically, different time window sizes can be used to process the entire process of the present invention respectively, and the time window corresponding to the result with the best effect is selected according to the processing effect.

[0102] (2) At the same sampling time as step (1), perform a channel cycle and repeat step (1) to obtain the output value at the corresponding midpoint position on each channel;

[0103] (3) After calculating the results of all channels at a sampling time in step (2), the sampling time loop is performed again, and steps (1) and (2) are repeated to obtain the output values ​​of all sampling times and channel directions.

[0104] Step 5: Output the denoised data.

[0105] The data after noise median filtering is output as a two-dimensional array according to the time sequence and channel number, which is the denoised data.

[0106] The present invention also provides a computer device, and an embodiment of the computer device is as follows:

[0107] [Example 4]

[0108] The computer device comprises a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor performs the following steps:

[0109] Step 1: Input the original DAS data;

[0110] The original DAS data is the original data collected by the distributed optical fiber sensing DAS, including channel data and sampling time.

[0111] Step 2: Extract the noise standard track;

[0112] All channel data in the original DAS data are superimposed, and the superimposed data is used as the noise standard channel;

[0113] The third step is noise matching filtering. The specific operations include:

[0114] Matching filtering is performed on the noise standard channel and the original DAS data channel by channel, and the matched filtering method can adopt the existing technology;

[0115] The valid signal data after matched filtering is retained.

[0116] The fourth step is noise median filtering. The specific operations include:

[0117] (1) For the data output by the matched filter in the third step, at a sampling time, take a channel in the channel direction, take a time window with the sample point corresponding to the channel as the midpoint (that is, at the sampling time, take a time window on different channels with the taken channel as the center), obtain the median of the sample points in the time window (median is a basic concept in mathematical statistics, which is to sort the data according to the size of the value and take the value of the middle data), subtract the median of the sample points from the midpoint value, and use the output value at the midpoint position;

[0118] The size of the time window can be determined by the test results. Specifically, different time window sizes can be used to process the entire process of the present invention respectively, and the time window corresponding to the result with the best effect is selected according to the processing effect.

[0119] (2) At the same sampling time as step (1), perform a channel cycle and repeat step (1) to obtain the output value at the corresponding midpoint position on each channel;

[0120] ①(3) After calculating the results of all channels at a sampling time in step (2), perform a sampling time loop again, repeat steps (1) and (2), and obtain the output values ​​of all sampling times and channel directions;

[0121] Step 5: Output the denoised data.

[0122] The data after noise median filtering is output as a two-dimensional array according to the time sequence and channel number, which is the denoised data.

[0123] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0124] The above technical solution is only one implementation mode of the present invention. For those skilled in the art, it is easy to make various types of improvements or modifications based on the principles disclosed in the present invention, and it is not limited to the technical solution described in the above specific embodiments of the present invention. Therefore, the above description is only preferred and does not have a restrictive meaning.

Claims

1. A distributed optical fiber data common mode noise elimination method, characterized in that: The original DAS data is subjected to noise matched filtering and noise median filtering in turn to obtain denoised data.

2. The distributed optical fiber data common mode noise elimination method according to claim 1, characterized in that: The method comprises the following steps: Input raw DAS data; Extract the noise standard track; Noise matched filtering; Noise median filtering; Output denoised data.

3. The method for eliminating common mode noise of distributed optical fiber data according to claim 2, characterized in that: The original DAS data is the original data collected by the distributed optical fiber sensing DAS, including channel data and sampling time.

4. The method for eliminating common mode noise of distributed optical fiber data according to claim 2, characterized in that: The specific operation of extracting the noise standard channel includes: All channel data in the original DAS data are superimposed and the superimposed data are used as the noise standard channel.

5. The method for eliminating common mode noise of distributed optical fiber data according to claim 2, characterized in that: The noise matched filtering specifically includes: Match filtering is performed on the noise standard channel and the original DAS data channel by channel; The valid signal data after matched filtering is retained.

6. The method for eliminating common mode noise of distributed optical fiber data according to claim 2, characterized in that: The noise median filtering specifically includes the following operations: (1) For the data output by the matched filter, at a sampling time, a channel is selected in the channel direction, a sample point corresponding to the channel is taken as the midpoint, a time window is selected, the median value of the sample points in the time window is obtained, and the median value of the sample points is subtracted from the midpoint value to obtain the output value at the midpoint position; (2) At the same sampling time as step (1), perform a channel cycle and repeat step (1) to obtain the output value at the corresponding midpoint position on each channel; (3) After calculating the results of all channels at a sampling time in step (2), the sampling time loop is performed again, and steps (1) and (2) are repeated to obtain the output values ​​of all sampling times and channel directions.

7. The distributed optical fiber data common mode noise elimination method according to claim 2, characterized in that: The output denoised data is specifically: The data after noise median filtering is output as a two-dimensional array according to the time sequence and channel number, which is the denoised data.

8. A distributed optical fiber data common mode noise elimination system, characterized in that: include: An input unit, used to input raw DAS data; An extraction unit, connected to the input unit, for extracting a noise standard channel; A matched filtering unit, connected to the extraction unit, for noise matched filtering; A median filter unit, connected to the matched filter unit, for performing noise median filtering; The output unit is connected to the median filter unit and is used to output the denoised data.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores at least one computer-executable program, and when the at least one program is executed by the computer, the computer executes the steps in the distributed optical fiber data common mode noise elimination method according to any one of claims 1 to 7.

10. A computer device comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the distributed optical fiber data common mode noise elimination method according to any one of claims 1 to 7.

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