CN108709661B - Data processing method and device for distributed optical fiber temperature measurement system - Google Patents
Data processing method and device for distributed optical fiber temperature measurement system Download PDFInfo
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- CN108709661B CN108709661B CN201810834271.5A CN201810834271A CN108709661B CN 108709661 B CN108709661 B CN 108709661B CN 201810834271 A CN201810834271 A CN 201810834271A CN 108709661 B CN108709661 B CN 108709661B
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Abstract
The invention relates to a data processing method and device for a distributed optical fiber temperature measurement system. A data processing method for a distributed optical fiber temperature measurement system is provided, which comprises the following steps: collecting multiple groups of optical time domain reflection signals in the same sensing optical fiber in multiple sampling rounds through time division delay; carrying out interpolation synthesis on the collected multiple groups of optical time domain reflection signals according to the sequence of the multiple groups of optical time domain reflection signals corresponding to the spatial positions on the sensing optical fiber; and smoothing the optical time domain reflection signal after interpolation synthesis to obtain a signal after noise reduction. By using the data processing method, the spatial resolution is improved under the condition of low sampling rate limitation, and the signal to noise ratio of the signal is improved, so that the temperature measurement precision of the distributed optical fiber temperature measurement system is improved. The application also provides a data processing device for the distributed optical fiber temperature measurement system, the distributed optical fiber temperature measurement system comprising the data processing device and a computer readable storage medium.
Description
Technical Field
The invention relates to the technical field of distributed optical fiber temperature measurement, in particular to a data processing method and device for a distributed optical fiber temperature measurement system.
Background
The distributed optical fiber temperature measurement technology is a novel temperature measurement technology and has the advantages of intrinsic safety, accurate temperature measurement, large monitoring range, no electromagnetic interference and the like. Due to the limitation of hardware cost and algorithm, the problems of insufficient spatial resolution and low temperature measurement precision commonly exist in the conventional distributed optical fiber temperature measurement equipment, and the defects reduce the detection capability of the distributed optical fiber temperature measurement equipment.
The spatial resolution is generally improved by increasing the data sampling rate and reducing the pulse width of the probe light. However, reducing the pulse width of the detection light further reduces the signal-to-noise ratio of the optical signal, and finally deteriorates the temperature measurement accuracy. The above problem is usually solved by using Coded Optical Time Domain Reflectometry (COTDR) or Optical Frequency Domain Reflectometry (OFDR), but the implementation is rather complicated and costly. The problems of cost pressure, difficulty in implementation and the like exist when the data sampling rate is improved by a hardware method. In addition, no effective noise reduction method is available at present to improve the temperature measurement precision.
Disclosure of Invention
Therefore, it is necessary to provide a data processing method and apparatus capable of effectively improving the spatial resolution and the temperature measurement accuracy of the distributed optical fiber temperature measurement system, in order to solve the above problems.
According to one aspect of the invention, a data processing method for a distributed optical fiber temperature measurement system is provided, which comprises the following steps: collecting multiple groups of optical time domain reflection signals in the same sensing optical fiber in multiple sampling rounds through time division delay; carrying out interpolation synthesis on the collected multiple groups of optical time domain reflection signals according to the sequence of the multiple groups of optical time domain reflection signals corresponding to the spatial positions on the sensing optical fiber; and smoothing the optical time domain reflection signal after interpolation synthesis to obtain a signal after noise reduction.
In one embodiment, acquiring multiple sets of optical time domain reflection signals in the same sensing fiber through time division delay in multiple sampling rounds includes: sequentially outputting a plurality of clock signals with corresponding phase changes in a plurality of sampling turns; generating a corresponding trigger pulse signal through the control of a clock signal corresponding to the trigger pulse signal in each sampling turn, and triggering a laser of the distributed optical fiber temperature measurement system to generate a laser pulse signal through the trigger pulse signal; generating a corresponding data acquisition starting signal after the trigger pulse signal corresponding to the data acquisition starting signal is finished in each sampling turn, so that the time difference between the generation time of the data acquisition signal in the plurality of sampling turns and the generation time of the corresponding trigger pulse signal is changed at equal intervals in sequence; and collecting the optical time domain reflection signal in each sampling round.
In one embodiment, after smoothing the interpolated synthesized optical time domain reflection signal to obtain a noise-reduced signal, the data processing method further includes: carrying out peak value detection on the noise-reduced signal to obtain peak information in the noise-reduced signal; and carrying out deconvolution processing on the noise-reduced signal according to the peak information.
In one embodiment, deconvoluting the noise-reduced signal according to the peak information includes: according to the wave crest information, performing signal separation operation on the signal subjected to noise reduction so as to separate a slowly-varying signal from a wave crest signal in the signal; storing the slowly varying signal; carrying out deconvolution operation on the peak signals; and performing signal recovery operation on the slowly-changed signal and the wave crest signal after deconvolution operation.
In one embodiment, the peak information includes the position of the peak, the peak height, and the peak width.
In one embodiment, the signal recovery operation is performed by adding the deconvolved peak signal to the stored ramp signal.
In one embodiment, the data smoothing process adopts smoothing filtering, and parameters of the smoothing filtering are adjusted according to the spatial resolution and the temperature measurement precision required by the distributed optical fiber temperature measurement system.
According to another aspect of the present invention, there is provided a computer readable storage medium having stored thereon a computer program, characterized in that the program, when executed by a processor, implements the steps of the data processing method for a distributed fiber thermometry system according to any of the embodiments described above.
According to still another aspect of the present invention, there is provided a data processing apparatus for a distributed optical fiber thermometry system, comprising: the time division delay sampling unit is used for acquiring a plurality of groups of optical time domain reflection signals in the same sensing optical fiber in a plurality of sampling rounds through time division delay; the data synthesis unit is used for carrying out interpolation synthesis on the collected multiple groups of optical time domain reflection signals according to the sequence of the multiple groups of optical time domain reflection signals corresponding to the spatial positions on the sensing optical fiber; and the data smoothing processing unit is used for smoothing the optical time domain reflection signal after interpolation synthesis to obtain a signal after noise reduction.
According to another aspect of the invention, a distributed optical fiber temperature measurement system is provided, which comprises a sensing optical fiber, a laser and the data processing device.
By applying the data processing method for the distributed optical fiber temperature measurement system, the data processing device for the distributed optical fiber temperature measurement system, the distributed optical fiber temperature measurement system and the computer readable storage medium, the spatial resolution is improved under the condition of low sampling rate limitation because a plurality of groups of optical time domain reflection signals in the same sensing optical fiber are acquired through time division delay in a plurality of sampling rounds and the acquired groups of data are subjected to interpolation synthesis according to the spatial position sequence. Meanwhile, the optical time domain reflection signal after interpolation synthesis is subjected to smoothing processing to obtain a signal after noise reduction, so that the signal to noise ratio of the signal is improved, and the temperature measurement precision of the distributed optical fiber temperature measurement system is improved.
Drawings
FIG. 1 shows a flow diagram of a data processing method for a distributed fiber optic thermometry system in one embodiment of the present application.
Fig. 2 shows a flowchart of step S110 of the data processing method in fig. 1.
Fig. 3 shows a schematic diagram of a trigger pulse signal and a data acquisition start signal in multiple sampling rounds in an embodiment of the present application.
Fig. 4A-4B are schematic diagrams respectively illustrating a plurality of sets of optical time domain reflection signals acquired according to the trigger pulse signal and the data acquisition start signal in the plurality of sampling rounds illustrated in fig. 3 and data obtained after interpolation synthesis of the plurality of sets of optical time domain reflection signals.
FIG. 5 shows a flow chart of a data processing method for a distributed fiber optic thermometry system in another embodiment of the present application.
Fig. 6 shows a flowchart of step S150 of the data processing method in fig. 5.
Fig. 7 shows a schematic diagram of the smoothed signal as a function of distance according to the present application.
Fig. 8 shows a schematic diagram of a peak signal obtained after peak detection and signal separation of the signal in fig. 7.
Fig. 9 shows schematic diagrams before and after performing a deconvolution operation on the peak signal in fig. 8.
Fig. 10 is a diagram showing a signal obtained after a signal recovery operation is performed on the peak signal after the deconvolution operation in fig. 9 and a signal that has not been subjected to deconvolution processing after smoothing processing.
FIG. 11 shows a schematic diagram of a data processing device for a distributed fiber optic thermometry system in one embodiment of the present application.
FIG. 12 shows a schematic diagram of a data processing device for a distributed fiber optic thermometry system in another embodiment of the present application.
DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.
It will be understood that when an element is referred to as being "formed on" another element, it can be directly formed on the other element or intervening elements may also be present. The terms "upper", "lower", and the like as used herein are for illustrative purposes only and do not denote a single embodiment.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
The application provides a data processing method for a distributed optical fiber temperature measurement system, which comprises the following steps: collecting multiple groups of optical time domain reflection signals in the same sensing optical fiber in multiple sampling rounds through time division delay; carrying out interpolation synthesis on the collected multiple groups of optical time domain reflection signals according to the sequence of the multiple groups of optical time domain reflection signals corresponding to the spatial positions on the sensing optical fiber; and smoothing the optical time domain reflection signal after interpolation synthesis to obtain a signal after noise reduction.
In the data processing method, multiple groups of optical time domain reflection signals in the same sensing optical fiber are acquired through time division delay in multiple sampling rounds, and the obtained multiple groups of data are subjected to interpolation synthesis according to the spatial position sequence, so that the spatial resolution is improved under the condition of low sampling rate limitation. Meanwhile, the optical time domain reflection signal after interpolation synthesis is subjected to smoothing processing to obtain a signal after noise reduction, so that the signal to noise ratio of the signal is improved, and the temperature measurement precision of the distributed optical fiber temperature measurement system is improved.
Based on the above scheme, the following detailed description is provided for specific embodiments with reference to the accompanying drawings.
The data processing method is applied to the distributed optical fiber temperature measurement system. The distributed optical fiber temperature measurement system comprises a sensing optical fiber and a laser. The laser emits a laser pulse signal that is coupled into and propagates in the sensing fiber. As the laser pulses travel through the fiber, they interact with the fiber molecules and undergo various forms of scattering, such as rayleigh, brillouin and raman scattering. Because rayleigh scattering is not sensitive to temperature; the Brillouin scattering is sensitive to temperature and stress, and is easily interfered by external environment to influence the measurement accuracy; the raman scattering is only sensitive to temperature, so the existing distributed optical fiber temperature measurement technology usually performs optical fiber temperature measurement based on the temperature effect mechanism of the raman scattering. Wherein the raman scattering effect produces stokes light and anti-stokes light.
The distributed optical fiber temperature measurement system senses and transmits temperature information of all points along the axial direction of the optical fiber by utilizing the self nonlinear optical effect of the common optical fiber. By means of optical time domain reflection technology, high power optical pulse signal is sent to optical fiber, and the reflected light strength inside the optical fiber is collected for analysis, so that the real-time temperature and change of all the points in the optical fiber may be detected accurately. Therefore, the distributed optical fiber temperature measurement system utilizes the medium of the optical fiber to form a one-dimensional continuously distributed sensing detector, so that the temperature information of continuous multiple points can be sensed simultaneously. The temperature information of each position of the optical fiber is obtained by collecting optical time domain reflection signals of each position of the optical fiber and according to the collected optical time domain reflection signals.
The present application provides a data processing method for a distributed fiber optic thermometry system, as shown in fig. 1, which shows a flow chart of one embodiment of the data processing method. The data processing method comprises the following steps:
step S110, collecting multiple groups of optical time domain reflection signals in the same sensing optical fiber through time division delay in multiple sampling rounds.
Specifically, a set of optical time domain reflection signals is collected in the sensing fiber in each sampling round, the set of optical time domain reflection signals corresponding to different spatial positions on the fiber, and the spacing of the spatial positions depends on the sampling frequency. And time-division delay sampling is carried out in a plurality of sampling rounds, so that the spatial positions of the collected groups of optical time domain reflection signals are translated integrally.
And step S120, carrying out interpolation synthesis on the collected multiple groups of optical time domain reflection signals according to the sequence of the multiple groups of optical time domain reflection signals corresponding to the spatial positions on the sensing optical fibers.
Specifically, as the spatial positions of the collected multiple groups of optical time domain reflection signals are translated on the whole, the collected multiple groups of optical time domain reflection signals can be interpolated and synthesized according to the sequence that the multiple groups of optical time domain reflection signals correspond to the spatial positions on the sensing optical fiber to form a group of optical time domain reflection signals, and the interval between the groups of optical time domain reflection signals corresponding to the spatial positions on the sensing optical fiber is reduced, so that the spatial resolution is improved.
Step S130, performing smoothing processing on the interpolated optical time domain reflection signal to obtain a noise-reduced signal.
Specifically, in order to improve the signal-to-noise ratio of the interpolated and synthesized optical time domain reflection signal, the interpolated and synthesized optical time domain reflection signal is smoothed to obtain a noise-reduced signal, so that the temperature measurement accuracy is improved. In one embodiment, the data smoothing process employs smoothing filtering, and parameters of the smoothing filtering can be adjusted according to the spatial resolution and temperature measurement accuracy required by the distributed optical fiber temperature measurement system. In one embodiment, the parameters of the smoothing filter include the width of the data to be smoothed, i.e. how many data are smoothed per adjacent data.
By applying the data processing method, a plurality of groups of optical time domain reflection signals in the same sensing optical fiber are acquired through time division delay in a plurality of sampling rounds, and the acquired data are subjected to interpolation synthesis according to the spatial position sequence, so that the spatial resolution is improved under the condition of low sampling rate limitation. Meanwhile, the optical time domain reflection signal after interpolation synthesis is subjected to smoothing processing to obtain a signal after noise reduction, so that the signal to noise ratio of the signal is improved, and the temperature measurement precision of the distributed optical fiber temperature measurement system is improved.
In one embodiment, a data processing method of the present application includes:
collecting multiple groups of optical time domain reflection signals in the same sensing optical fiber in multiple sampling rounds through time division delay;
carrying out interpolation synthesis on the collected multiple groups of optical time domain reflection signals according to the sequence of the multiple groups of optical time domain reflection signals corresponding to the spatial positions on the sensing optical fiber to obtain a group of data after interpolation synthesis;
repeating the two steps for multiple times to obtain multiple groups of optical time domain reflection signals after interpolation synthesis;
accumulating and averaging the obtained multiple groups of optical time domain reflection signals after interpolation synthesis to obtain a group of optical time domain reflection signals after preliminary noise reduction; and
and smoothing the optical time domain reflection signal subjected to the preliminary noise reduction to obtain an optical time domain reflection signal subjected to further noise reduction.
By applying the data processing method, multiple sampling rounds and interpolation synthesis are repeated for multiple times, so that multiple groups of optical time domain reflection signals subjected to interpolation synthesis are obtained and are subjected to accumulation averaging, and then the signals subjected to accumulation averaging are subjected to smoothing processing, so that the spatial resolution is improved, the signal to noise ratio of the signals is further improved, and the spatial resolution and the temperature measurement precision of the distributed optical fiber temperature measurement system are further obviously improved.
In one embodiment, as shown in FIG. 2, a flowchart of step S110 of the data processing method of FIG. 1 is shown. Step S110, collecting multiple groups of optical time domain reflection signals in the same sensing fiber through time division delay in multiple sampling rounds, including:
in step S111, a plurality of clock signals with corresponding phase changes are sequentially output in a plurality of sampling rounds.
Specifically, a corresponding one of the clock signals is output in each sampling round, and phases of the corresponding clock signals in the plurality of sampling rounds are different. For example, when n times of sampling are performed, the phase difference of the clock signals corresponding to the adjacent sampling turns is 2 π/n, and the phases of the n clock signals in the n times of sampling are 2 π/n, 4 π/n, … … (n-1)2 π/n and 2 π in this order.
And step S112, generating a corresponding trigger pulse signal under the control of a clock signal corresponding to the trigger pulse signal in each sampling round, wherein the trigger pulse signal triggers a laser of the distributed optical fiber temperature measurement system to generate a laser pulse signal.
Specifically, the trigger pulse signal is a high or low level pulse signal generated by clock signal control. The generation of the trigger pulse signal is controlled by the corresponding clock signal in each sampling round. The triggering pulse signal triggers a laser of the distributed optical fiber temperature measuring system to generate a laser pulse signal, and the generated laser pulse signal is coupled to the sensing optical fiber and is transmitted in the sensing optical fiber.
And step S113, generating a corresponding data acquisition starting signal after the trigger pulse signal corresponding to the data acquisition starting signal is finished in each sampling turn, so that the time difference between the generation time of the data acquisition signal in the plurality of sampling turns and the generation time of the corresponding trigger pulse signal is sequentially changed at equal intervals.
Specifically, the data acquisition start signal controls the time for starting to acquire data, that is, the time for starting to acquire the optical time domain reflection signal in the sensing optical fiber, and the difference between the generation time of the trigger pulse signal in two adjacent sampling rounds and the generation time of the corresponding data acquisition start signal is fixed to Δ. As shown in fig. 3, a schematic diagram of the generation time of the data acquisition start signal and the generation time of the trigger pulse signal in a plurality of sampling rounds is shown. In fig. 3, the time intervals between the trigger pulse signal and the data acquisition start signal are X, X + Δ, X +2 Δ … … X + (n-1) Δ in this order over a plurality of sampling rounds. A time interval Y from the end time of the trigger pulse signal in the 1 st sampling round to the generation time of the data acquisition start signal may be set. In one embodiment, the time interval Y is less than the length of the fiber multiplied by 2 divided by the speed of light traveling in the fiber.
Step S114, collecting optical time domain reflection signals in each sampling round.
Specifically, after the data acquisition start signal is generated, the optical time domain reflection signal starts to be acquired in each sampling round. Because the time intervals between the trigger pulse signals and the data acquisition start signals in the multiple sampling rounds are sequentially changed at equal intervals, the spatial positions of the optical time domain reflection signals acquired in two adjacent sampling rounds on the corresponding sensing optical fiber are integrally translated by c delta/2 (wherein c is the propagation speed of laser in the optical fiber, and delta is the difference value of the time intervals from the generation time of the trigger pulse signals in two adjacent sampling rounds to the generation time of the corresponding data acquisition start signals), so that multiple groups of optical time domain reflection signals with the translated spatial positions are obtained.
Fig. 4A shows n sets of optical time domain reflection signals acquired in n samples according to the trigger pulse signal and the data acquisition start signal shown in fig. 3, and fig. 4B shows data obtained by performing interpolation synthesis on the n sets of optical time domain reflection signals in a spatial sequence. In fig. 4A, the data in each sampling contains m data corresponding to m positions on the optical fiber. The interpolated data in fig. 4B corresponds to n times m data at n times m positions on the fiber. Therefore, the spatial resolution of the distributed optical fiber temperature measurement system is obviously improved along with the increase of the sampling turn n. The sampling times can be determined according to the requirement of the spatial resolution of the distributed optical fiber temperature measurement system and the response time of the system. In one embodiment, the sampling round n may be determined to be 2-8 times. Specifically, it can be determined that 2 samples are taken within one clock cycle. It may also be determined that 4 samples are taken within one clock cycle. It may also be determined that 8 samples are taken within one clock cycle. In this regard, the present embodiment is not limited thereto. And then, carrying out data smoothing treatment on the interpolated data, and improving the signal-to-noise ratio, thereby improving the temperature measurement precision of the optical fiber temperature measurement system.
In one embodiment, the above process (n sampling rounds) is repeated k times, the value of k may be changed as required, and during or after the repetition process, the optical time domain reflection signals at the same optical fiber position are added and then averaged to complete the process of accumulating average noise reduction and obtain a set of data after preliminary noise reduction. And carrying out smooth filtering on the data subjected to the preliminary noise reduction to obtain the data subjected to the further noise reduction, so that the signal-to-noise ratio of the sampled data is improved, and the temperature measurement precision is improved.
In one embodiment, an FPGA (Field-Programmable Gate Array) is used as a main controller for controlling generation and delay of the trigger pulse signal and generation of the data acquisition start signal, so as to control data acquisition, and the FPGA is also used for controlling data processing, such as data accumulation averaging, interpolation synthesis, smoothing processing, and the like, so as to improve spatial resolution and temperature measurement accuracy of the existing system without changing a hardware circuit, and more accurately reflect detected temperature information. In another embodiment, an FPGA may be used to control the acquisition of data and the processing of the data by a processor downstream of the FPGA.
By applying the data processing method, a plurality of trigger pulse signals with time delay are generated by controlling a plurality of clock signals with different phases, so that a plurality of groups of optical time domain reflection signals with shifted spatial positions are collected, the plurality of groups of optical time domain reflection signals are subjected to interpolation synthesis according to the spatial position sequence to obtain a group of optical time domain reflection signals, and the temperature information of the corresponding position on the optical fiber is obtained according to the group of optical time domain reflection signals, so that the spatial resolution of the distributed optical fiber sampling system is improved under the condition of low sampling rate limitation.
According to the method and the device, after interpolation synthesis, data smoothing processing is carried out on the obtained optical time domain reflection signals to obtain the signals after noise reduction, the signal to noise ratio is improved, and the temperature measurement precision of the optical fiber temperature measurement system is improved. Considering that the data smoothing process helps to improve the signal-to-noise ratio, but also causes the spatial resolution to be reduced, the data processing method in the present application further includes performing deconvolution processing on the noise-reduced data to improve the spatial resolution of the optical fiber thermometry system. The above-described data processing method will be described below with reference to the embodiments and the drawings.
In one embodiment, as shown in FIG. 5, a flow chart of a data processing method for a distributed fiber optic thermometry system of the present application is shown. The data processing method shown in fig. 5 is different from the data processing method shown in fig. 1 in that the data processing method shown in fig. 5 further includes:
step S140, performing peak detection on the noise-reduced signal to obtain peak information in the noise-reduced signal.
Specifically, the noise-reduced signal includes a peak signal on an echo signal due to the ambient temperature. And carrying out peak value detection on the noise-reduced signal to obtain peak information. Wherein the peak information includes a position of a peak, a peak height, and a peak width.
And S150, performing deconvolution processing on the noise-reduced signal according to the peak information.
In particular, deconvolution can be applied in the fields of image processing, signal processing, and spectral detection. The result obtained by the deconvolution operation is equivalent to the reduction of the optical pulse width, and therefore contributes to the improvement of the spatial resolution. And after the peak value detection is carried out on the signal subjected to noise reduction, carrying out deconvolution processing on the signal subjected to noise reduction according to the detected peak information. Since the deconvolution processing is mainly directed to the peak signal in the noise-reduced signal, it is necessary to acquire peak information first.
By applying the data processing method, the peak value detection is carried out on the signal after noise reduction so as to obtain the peak information in the signal after noise reduction, and the signal after noise reduction is subjected to deconvolution processing according to the peak information, so that the spatial resolution of the distributed optical fiber temperature measurement system is improved.
In one embodiment, as shown in FIG. 6, a flowchart of step S150 in the data processing method shown in FIG. 5 is shown. Step S150, carrying out deconvolution processing on the signal after noise reduction according to the peak information, comprising the following steps:
and step S151, performing a signal separation operation on the noise-reduced signal according to the peak information to separate the slowly-varying signal from the peak signal in the signal.
Specifically, the noise-reduced signal includes a peak signal and a ramp signal, and the ramp signal corresponding to the peak signal is a reference signal for the peak signal to change. Since the deconvolution operation is mainly performed on the peak signal, it is necessary to separate the slowly varying signal from the noise-reduced signal. The signal separation operation needs to be based on peak information such as the position of the peak, the peak height and the peak width, etc. In one embodiment, the signal splitting operation includes: after peak detection, a plurality of data are respectively taken before and after the peak signal to perform slow signal fitting to obtain a slow signal, and then the slow signal at the corresponding position is subtracted from the peak signal to obtain a peak signal after signal separation. Fig. 7 shows a graph of the amplitude of the signal obtained after data smoothing of the interpolated data as a function of distance (i.e. spatial position on the fiber). As can be seen from fig. 7, the smoothed signal includes a peak signal and a ramp signal. Fig. 8 shows a schematic diagram of a peak signal obtained after performing peak detection and signal separation on the smoothed signal in fig. 7. The range of signals over which the deconvolution operation is performed is also indicated in fig. 8.
In this embodiment, it may also be determined whether to perform a signal separation operation on the peak signal corresponding to the peak information according to the detected peak information. Specifically, the condition for performing the signal separation operation on the peak signal corresponding to the peak information may be set according to actual conditions and requirements, for example, a peak width threshold and/or a peak height threshold may be set. Specifically, the signal separation operation is performed on the peak signal corresponding to the peak information when the peak width and/or the peak height of the detected peak satisfy a threshold condition. For example, the signal separation operation is performed on the peak signal corresponding to the peak information when the peak width of the detected peak is smaller than a preset peak width threshold, or the signal separation operation is performed on the peak signal corresponding to the peak information when the detected peak height is larger than a preset peak height threshold, or the signal separation operation is performed on the peak signal corresponding to the peak information when the peak width of the detected peak is smaller than the preset peak width threshold and the detected peak height is larger than the preset peak height threshold. And if the threshold condition is not met, the peak signal corresponding to the peak information is not subjected to the gradual signal separation operation.
Step S152 stores the ramp signal.
Specifically, the ramp signal is stored in the storage unit.
In step S153, deconvolution is performed on the peak signal.
Specifically, fig. 9 shows schematic diagrams before and after performing a deconvolution operation on the peak signal in fig. 8. Wherein the dotted line is a schematic diagram of the peak signal before the deconvolution operation, and the solid line is a schematic diagram of the peak signal after the deconvolution operation. It can be seen that the peak width of the peak signal after the deconvolution operation becomes narrow, and the peak height becomes high. The deconvolution operation can effectively reduce the influence of integral broadening in the photoelectric detection process and eliminate errors caused by deconvolution under low resolution, the pulse signal width is equivalently compressed through the deconvolution operation, and the spatial resolution is further improved. In the present embodiment, the deconvolution algorithm may be a Jansson deconvolution, a Wiener deconvolution, a Gold deconvolution, or an FFT-based deconvolution, but is not limited to the above convolution algorithms.
In step S154, a signal recovery operation is performed on the slowly varying signal and the peak signal after the deconvolution operation.
Specifically, fig. 10 shows a schematic diagram of a signal after a signal recovery operation is performed on the ramp signal and the peak signal after the deconvolution operation in fig. 9, and a signal after smoothing processing without deconvolution processing. In one embodiment, the signal recovery operation is performed by adding the deconvolved peak signal to the stored ramp signal. And performing signal recovery operation on the slowly-varying signal and the wave crest signal after deconvolution operation to obtain a recovered signal, and acquiring temperature distribution on the corresponding sensing optical fiber according to the recovered signal.
By applying the data processing, signal separation operation is carried out on the signal subjected to noise reduction according to wave crest information to obtain a wave crest signal and a slowly-varying signal, deconvolution is carried out on the wave crest signal, and signal recovery operation is carried out on the slowly-varying signal and the wave crest signal subjected to deconvolution operation to obtain a signal subjected to deconvolution processing, and then the temperature of the corresponding position of the optical fiber is obtained according to the signal subjected to deconvolution processing.
The present application also provides a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, performs the steps of: collecting multiple groups of optical time domain reflection signals in the same sensing optical fiber in multiple sampling rounds through time division delay; carrying out interpolation synthesis on the collected multiple groups of optical time domain reflection signals according to the sequence of the multiple groups of optical time domain reflection signals corresponding to the spatial positions on the sensing optical fiber; and smoothing the optical time domain reflection signal after interpolation synthesis to obtain a signal after noise reduction.
In one embodiment, collecting multiple sets of optical time domain reflection signals in the same sensing fiber through time division delay in multiple sampling rounds comprises: sequentially outputting a plurality of clock signals with corresponding phase changes in a plurality of sampling turns; generating a corresponding trigger pulse signal through the control of a clock signal corresponding to the trigger pulse signal in each sampling turn, and triggering a laser of the distributed optical fiber temperature measurement system to generate a laser pulse signal through the trigger pulse signal; generating a corresponding data acquisition starting signal after the trigger pulse signal corresponding to the data acquisition starting signal is finished in each sampling turn, so that the time difference between the generation time of the data acquisition signal in the plurality of sampling turns and the generation time of the corresponding trigger pulse signal is changed at equal intervals in sequence; and collecting the optical time domain reflection signal in each sampling round.
In one embodiment, after smoothing the interpolated synthesized optical time domain reflection signal to obtain a noise-reduced signal, the data processing method further includes: carrying out peak value detection on the noise-reduced signal to obtain peak information in the noise-reduced signal; and carrying out deconvolution processing on the noise-reduced signal according to the peak information.
In one embodiment, deconvoluting the noise-reduced signal according to the peak information includes: according to the wave crest information, performing signal separation operation on the signal subjected to noise reduction so as to separate a slowly-varying signal from a wave crest signal in the signal; storing the slowly varying signal; carrying out deconvolution operation on the peak signals; and performing signal recovery operation on the slowly-changed signal and the wave crest signal after deconvolution operation.
In one embodiment, the peak information includes a position of a peak, a peak height, and a peak width.
In one embodiment, the signal recovery operation is performed by adding the deconvolved peak signal to the stored ramp signal.
In one embodiment, the data smoothing process adopts smoothing filtering, and parameters of the smoothing filtering are adjusted according to the spatial resolution and the temperature measurement precision required by the distributed optical fiber temperature measurement system.
It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by hardware instructions of a computer program, which can be stored in a non-volatile computer-readable storage medium, and when executed, can include the processes of the embodiments of the methods described above. Any reference to memory, storage, database, or other medium used in the embodiments provided herein may include non-volatile and/or volatile memory, among others. Non-volatile memory can include read-only memory (ROM), Programmable ROM (PROM), Electrically Programmable ROM (EPROM), Electrically Erasable Programmable ROM (EEPROM), or flash memory. Volatile memory can include Random Access Memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms such as Static RAM (SRAM), Dynamic RAM (DRAM), Synchronous DRAM (SDRAM), Double Data Rate SDRAM (DDRSDRAM), Enhanced SDRAM (ESDRAM), Synchronous Link DRAM (SLDRAM), Rambus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).
The present application further provides a data processing apparatus for a distributed optical fiber thermometry system, as shown in fig. 11, a schematic diagram of the data processing apparatus 1000 in an embodiment of the present application is shown. The data processing apparatus 1000 includes:
and the time division delay sampling unit 100 is used for acquiring multiple groups of optical time domain reflection signals in the same sensing optical fiber through time division delay in multiple sampling rounds.
And the data synthesis unit 200 is configured to perform interpolation synthesis on the collected multiple sets of optical time domain reflection signals according to the order of the multiple sets of optical time domain reflection signals corresponding to the spatial positions on the sensing optical fiber.
And a data smoothing unit 300, configured to smooth the interpolated synthesized optical time domain reflection signal to obtain a noise-reduced signal.
In one embodiment, the time-division delay sampling unit 100 is specifically configured to: sequentially outputting a plurality of clock signals with corresponding phase changes in a plurality of sampling turns; generating a corresponding trigger pulse signal through the control of a clock signal corresponding to the trigger pulse signal in each sampling turn, and triggering a laser of the distributed optical fiber temperature measurement system to generate a laser pulse signal through the trigger pulse signal; generating a corresponding data acquisition starting signal after the trigger pulse signal corresponding to the data acquisition starting signal is finished in each sampling turn, so that the time difference between the generation time of the data acquisition signal in the plurality of sampling turns and the generation time of the corresponding trigger pulse signal is changed at equal intervals in sequence; and collecting the optical time domain reflection signal in each sampling round.
In one embodiment, as shown in FIG. 12, a schematic diagram of a data processing device 2000 for a distributed fiber optic thermometry system of the present application is shown. The data processing apparatus 2000 differs from the data processing apparatus 1000 in fig. 11 in that the data processing apparatus 2000 further includes:
the peak detection unit 400 performs peak detection on the noise-reduced signal to acquire peak information in the noise-reduced signal.
The deconvolution processing unit 500 performs deconvolution processing on the noise-reduced signal according to the peak information.
In one embodiment, the deconvolution processing unit 500 is specifically configured to: according to the wave crest information, performing signal separation operation on the signal subjected to noise reduction so as to separate a slowly-varying signal from a wave crest signal in the signal; storing the slowly varying signal; carrying out deconvolution operation on the peak signals; and performing signal recovery operation on the slowly-changed signal and the wave crest signal after deconvolution operation.
In one embodiment, the peak information includes a position of a peak, a peak height, and a peak width.
In one embodiment, the signal recovery operation is performed by adding the deconvolved peak signal to the stored ramp signal.
In one embodiment, the data smoothing process adopts smoothing filtering, and parameters of the smoothing filtering are adjusted according to the spatial resolution and the temperature measurement precision required by the distributed optical fiber temperature measurement system.
The application also provides a distributed optical fiber temperature measurement system, which includes: sensing fiber, laser and data processing device according to any of the embodiments described above. The data processing device is used for collecting optical time domain reflection signals in the optical fiber and processing the optical time domain reflection signals. For a specific implementation principle of the data processing apparatus, reference may be made to the corresponding descriptions in fig. 11 and fig. 12, which are not described herein again.
The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above embodiments only express a few embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (9)
1. A data processing method for a distributed fiber optic thermometry system, the method comprising:
collecting multiple groups of optical time domain reflection signals in the same sensing optical fiber in multiple sampling rounds through time division delay;
carrying out interpolation synthesis on the collected multiple groups of optical time domain reflection signals according to the sequence of the multiple groups of optical time domain reflection signals corresponding to the spatial positions on the sensing optical fiber;
smoothing the interpolated optical time domain reflection signal to obtain a noise-reduced signal;
carrying out peak value detection on the noise-reduced signal to obtain peak information in the noise-reduced signal; and
and carrying out deconvolution processing on the noise-reduced signal according to the peak information.
2. The data processing method of claim 1, wherein the collecting multiple sets of optical time domain reflection signals in the same sensing fiber through time division delay in multiple sampling rounds comprises:
sequentially outputting a plurality of clock signals with corresponding phase changes in the plurality of sampling turns;
generating a corresponding trigger pulse signal through the control of a clock signal corresponding to the trigger pulse signal in each sampling turn, wherein the trigger pulse signal triggers a laser of the distributed optical fiber temperature measurement system to generate a laser pulse signal;
generating a corresponding data acquisition starting signal after the trigger pulse signal corresponding to the data acquisition starting signal is finished in each sampling turn, so that the time difference between the generation time of the data acquisition signal in the plurality of sampling turns and the generation time of the corresponding trigger pulse signal is changed at equal intervals in sequence; and
the optical time domain reflection signal is collected in each sampling round.
3. The data processing method according to claim 1, wherein the deconvoluting the noise-reduced signal according to the peak information comprises:
according to the peak information, performing signal separation operation on the noise-reduced signal to separate a slowly-varying signal from a peak signal in the signal;
storing the slowly varying signal;
carrying out deconvolution operation on the peak signal; and
and performing signal recovery operation on the slowly-changed signal and the wave crest signal after deconvolution operation.
4. The data processing method of claim 3, wherein the peak information includes a position of a peak, a peak height, and a peak width.
5. A data processing method according to claim 3, wherein the signal recovery operation is performed by adding the peak signal after the deconvolution operation to the stored ramp signal.
6. The data processing method of any one of claims 1 to 5, wherein the data smoothing process employs smoothing filtering, and parameters of the smoothing filtering are adjusted according to the spatial resolution and the temperature measurement precision required by the distributed optical fiber temperature measurement system.
7. A data processing apparatus for a distributed fiber optic thermometry system, comprising:
the time division delay sampling unit is used for acquiring a plurality of groups of optical time domain reflection signals in the same sensing optical fiber in a plurality of sampling rounds through time division delay;
the data synthesis unit is used for carrying out interpolation synthesis on the collected multiple groups of optical time domain reflection signals according to the sequence of the multiple groups of optical time domain reflection signals corresponding to the spatial positions on the sensing optical fiber; and
the data smoothing processing unit is used for smoothing the optical time domain reflection signal after interpolation synthesis to obtain a signal after noise reduction, carrying out peak value detection on the signal after noise reduction to obtain peak information in the signal after noise reduction, and carrying out deconvolution processing on the signal after noise reduction according to the peak information.
8. A distributed optical fiber thermometry system comprising a sensing fiber, a laser, and the data processing apparatus of claim 7.
9. A computer-readable storage medium, on which a computer program is stored, which program, when being executed by a processor, is adapted to carry out the steps of the data processing method according to any one of claims 1 to 6.
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| CN110160569B (en) * | 2019-04-24 | 2021-09-24 | 国网浙江省电力有限公司信息通信分公司 | Noise reduction method and system for distributed optical fiber sensing signal and storage medium |
| CN110207804B (en) * | 2019-06-21 | 2020-07-14 | 华中科技大学 | Discretization processing method based on single-mode fiber distributed acoustic sensing |
| CN110411602B (en) * | 2019-07-25 | 2020-10-16 | 深圳供电局有限公司 | Method for detecting and positioning local heating point of superconducting cable |
| CN110736877B (en) * | 2019-09-26 | 2021-09-28 | 山东信通电子股份有限公司 | High-speed acquisition method and device for time domain reflection signals |
| CN111765986A (en) * | 2020-07-07 | 2020-10-13 | 国兴汇金(深圳)科技有限公司 | Multiphase data acquisition method and system for DTS and storage medium |
| CN111928972B (en) * | 2020-08-06 | 2021-11-30 | 中国人民解放军海军工程大学 | Method and system for improving spatial resolution of distributed optical fiber temperature measurement system |
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