CN103424134B - The optical fiber sensing method that a kind of many reference amounts are measured simultaneously - Google Patents
The optical fiber sensing method that a kind of many reference amounts are measured simultaneously Download PDFInfo
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- CN103424134B CN103424134B CN201310326124.4A CN201310326124A CN103424134B CN 103424134 B CN103424134 B CN 103424134B CN 201310326124 A CN201310326124 A CN 201310326124A CN 103424134 B CN103424134 B CN 103424134B
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Abstract
The present invention relates to sensor technical field, particularly the optical fiber sensing method simultaneously measured of a kind of many reference amounts, collects a road observation data from a Fibre Optical Sensor acted on by many reference amounts simultaneously; Multichannel observation data is obtained by the method postponing certain sampled point; Carry out pre-service to the multichannel observation signal obtained, pre-service comprises centralization and albefaction; Utilize traditional blind signal separation technology, from observation signal, isolate multiple parameter; Corresponding signal transacting is done to isolated multiple parameter, obtain the effective information of parameter, beneficial effect of the present invention: use single channel blind signal separation technology, the many reference amounts achieving optical fiber sensing system are measured simultaneously, the method precision is high, and be easy to realize, the structure using the method to make fibre-optical multiparameter simultaneously measure sensor-based system simplifies, and cost reduces.
Description
Technical field
The present invention relates to sensor technical field, particularly the optical fiber sensing method simultaneously measured of a kind of many reference amounts.
Background technology
Vibration, temperature, stress etc. are some parameters often needing in productive life to measure.Under the productive life environment of reality, often multiple parameter acts on simultaneously, thus in order to adapt to the situation of reality, studying the method that multiple parameter measures simultaneously and having important practical significance.
For SMS optical fiber sensing system, at present, at SMS sensory field of optic fibre, for the method that many reference amounts are measured simultaneously, be mostly, based on multistage SMS optical fiber structure, to utilize the spectral characteristics such as wave length shift, the method structure is comparatively complicated, and need OSA be used, cost is higher, is not easy for the acquisition environment of reality.
Summary of the invention
In order to solve prior art problem, the embodiment of the invention discloses the optical fiber sensing method that a kind of many reference amounts are measured simultaneously.The optical fiber sensing method simultaneously measured based on the many reference amounts of single channel blind signal separation technology of the present invention, comprises the following steps:
Step 1) collects a road observation data from the Fibre Optical Sensor that is acted on by many reference amounts simultaneously;
Step 2) obtain multichannel observation data by the method postponing certain sampled point;
Step 3) carries out pre-service to the multichannel observation signal obtained, and pre-service comprises centralization and albefaction;
Step 4) utilizes traditional blind signal separation technology, isolates multiple parameter from observation signal;
Step 5) does corresponding signal transacting to isolated multiple parameter, obtains the effective information of parameter.
Described step 2) specifically comprise: delay sampling point is the data array will collected in the time period, the sampling number that Late phase is corresponding.
Described step 3) specifically comprise: data centerization process is and makes the average of signal be zero.For stochastic variable x (t), its centralization process can be expressed as
Wherein E [x (the t)] mathematical expectation that is stochastic variable x (t).In the signal processing of reality, the length N due to the observation signal obtained by sensor measurement is limited, and the mean value of sample data can be used to replace its mathematical expectation, then formula (1) can be rewritten as
After centralization process, the object simplifying single channel Blind Signal Separation algorithm can be reached.Described whitened signal processing intent removes the correlativity between each component, makes second-order statistics between each component of the signal after albefaction independent.Right
carry out linear transformation P, obtain
and R
u=E [u (t) u
t(t)]=I.(3)
Wherein R
ufor the covariance matrix of signal u (t) after albefaction, in u (t), each component is uncorrelated mutually.The main method of albefaction has three classes, is respectively principal component analysis (PCA) method, adaptive approach and sane whitening approach.Three kinds of methods are all applicable in the present invention, wherein only detailed descriptionthe PCA method.If
it is mean value signal
covariance matrix, namely
eigenvalues Decomposition is carried out to it, can obtain
From formula (4), we can obtain whitening matrix
P=D
(-1/2)FT，(5)
Wherein F is
feature matrix, D diagonal line is the diagonal matrix of eigenwert, its diagonal element λ
12, λ
22..., λ
m2for
eigenwert.Again
By formula (4), (5) are brought in formula (6), can obtain
R
u=(D
-1/2F
T)(FDF
T)(D
-1/2F
T)
T=I。(7)
Described step 4) specifically comprise: described traditional blind signal separation technology, its objective is and recover source signal from observation signal, namely by searching separation matrix W, passes through linear transformation
y(t)=Wx(t)，(8)
Wherein, x (t) is multichannel observation signal, and y (t) is the estimated signal of isolated source signal.The traditional blind signal separation technology used in the present invention is FastICA algorithm, and FastICA algorithm maximizes principle based on non-Gaussian system, uses fixed-point iteration theory to find W
tthe non-Gaussian system maximal value of x, this algorithm adopts a large amount of sampled points of Newton iterative to observational variable x to carry out batch processing, to maximize negentropy as objective function, isolates an independent component from observation signal at every turn.The iterative formula of FastICA algorithm is
w
+=E[Xg(w
Tu]-E[g'(w
Tu)]w，(9)
Wherein, u is mixed signal matrix, and g is nonlinear function, and w is a line in separation matrix W.If be input as whitening matrix u (t)=[u
1(t), u
2(t) ..., u
m(t)], export as independent matrix y (t)=[y
1(t), y
2(t) ..., y
m(t)].
The FastICA iterative algorithm step maximum based on negentropy is as follows:
4.1) m=0 is made, initialization weight vector w (0), i.e. random selecting one initial weight vector.
4.2)m=m+1。
4.3) w is adjusted, order
w(m+1)=E[ug(w
T(m)u)]-E[g'(w
T(m)u)]w(m),(11)
Nonlinear function need be chosen in advance.
4.4) normalized,
If algorithm is not restrained, then return 4.3).
4.5) algorithm convergence, obtains an independent component,
Described step 5) specifically comprise: described corresponding signal transacting, comprises and does FFT process to oscillating component, obtains vibration frequency information; Hilbert conversion is done to temperature components, obtains temperature information etc.
The present invention compared to existing technology tool has the following advantages: use single channel blind signal separation technology, the many reference amounts achieving optical fiber sensing system are measured simultaneously, and the method precision is high, and is easy to realize.The structure using the method to make fibre-optical multiparameter simultaneously measure sensor-based system simplifies, and cost reduces.
Accompanying drawing explanation
Fig. 1 is process flow diagram of the present invention.
Fig. 2 is SMS fibre-optical sensing device figure.
Fig. 3 be use SMS fibre-optical sensing device as shown in Figure 2 for while measuring vibrations and stress time the vibration that obtains and stress mixed signal curve;
Fig. 4 carries out the rear isolated stress signal curve of process for using single channel blind signal separation technology to the mixed signal shown in Fig. 3;
Fig. 5 carries out the rear isolated vibration signal curve of process for using single channel blind signal separation technology to the mixed signal shown in Fig. 3;
Fig. 6 processes for using FFT the spectrogram obtained to the vibration signal shown in Fig. 5;
Fig. 7 is the Temperature Scaling curve of SMS fibre-optical sensing device as shown in Figure 2;
Fig. 8 be use SMS fibre-optical sensing device as shown in Figure 2 for while measuring vibrations and temperature linearity change time the vibration that obtains and temperature linearity change Mixing Curve;
Fig. 9 uses single channel blind signal separation technology to carry out the rear isolated temperature variation signal curve of process to the mixed signal in Fig. 8;
Figure 10 uses single channel blind signal separation technology to carry out the rear isolated vibration signal curve of process to the mixed signal in Fig. 8;
Figure 11 obtains temperature variation curve after using the temperature variation signal shown in Hilbert transfer pair Fig. 9 to process;
Figure 12 is the spectrogram that obtains after using FFT to process the vibration signal shown in Figure 10;
Figure 13 be use SMS fibre-optical sensing device as shown in Figure 2 for while measuring vibrations and temperature natural trend time the vibration that obtains and temperature natural trend mixed signal curve;
Figure 14 uses single channel blind signal separation technology to carry out the rear isolated vibration signal curve of process to the mixed signal in Figure 13;
Figure 15 uses single channel blind signal separation technology to carry out the rear isolated temperature variation signal curve of process to the mixed signal in Figure 13;
Figure 16 is the spectrogram that obtains after using FFT to process the vibration signal shown in Figure 14;
Figure 17 obtains temperature variation curve after using the temperature variation signal shown in Hilbert transfer pair Figure 15 to process.
Embodiment
When considered in conjunction with the accompanying drawings, by referring to detailed description below, more completely can understand the present invention better and easily learn wherein many adjoint advantages, but accompanying drawing described herein is used to provide a further understanding of the present invention, forms a part of the present invention.
Referring to figs. 1 through Figure 17, embodiments of the invention are described.
For enabling above-mentioned purpose, feature and advantage become apparent more, and below in conjunction with the drawings and specific embodiments, the present invention is further detailed explanation.
The present invention realizes many reference amounts with single channel Blind Signal Separation and is measured as example simultaneously and is realized in SMS optical fiber sensing system.
As shown in Figure 1, a kind of optical fiber sensing method simultaneously measured based on the many reference amounts of single channel Blind Signal Separation, comprises the following steps:
Step 1) collects a road observation data from the Fibre Optical Sensor that is acted on by many reference amounts simultaneously;
Step 2) obtain multichannel observation data by the method postponing certain sampled point;
Step 3) carries out pre-service to the multichannel observation signal obtained, and pre-service comprises centralization and albefaction;
Step 4) utilizes traditional blind signal separation technology, isolates multiple parameter from observation signal;
Step 5) does corresponding signal transacting to isolated multiple parameter, obtains the effective information of parameter.
As shown in Figure 2, SMS fibre-optical sensing device, comprise laser instrument 201, SMS optical fiber, PIN pipe 207, data collecting card 208 and signal processor 209, described SMS optical fiber is formed by the first single-mode fiber 202, multimode optical fiber 204 and the second single-mode fiber 206 cascade, wherein said multimode optical fiber 204 comprises again the multimode optical fiber 203,204 for acting on different parameter respectively, and multiple parameter also can act on same section of multimode optical fiber simultaneously herein; Described laser instrument 201 exports first single-mode fiber 202 of the one end connecting SMS optical fiber, second single-mode fiber 206 inputs with PIN pipe 207 and is connected, PIN pipe 207 output inputs with data collecting card 208 and is connected, data collecting card 208 exports connection signal processor 209, described signal processor 209 utilizes SMS optical fiber Output optical power to carry intermode relative phase change information, obtains vibration, strain measurements.
As shown in Figures 3 to 6, the groundwork process of experiment is: play 10Hz audio frequency by sound equipment, make to be pasted on multimode optical fiber on sound vibration film with this frequency vibration, apply stress at other positions of multimode optical fiber simultaneously, applying stress time is about the 6s started when measuring, and the vibration collected and the mixed signal of stress are as shown in Figure 3.After the process of single channel blind signal separation technology, obtain stress signal as shown in Figure 4, the vibration signal obtained as shown in Figure 5, carries out FFT to the vibration signal in Fig. 5, and the spectrogram obtained as shown in Figure 6.Experimental result shows, the method at the same time measuring vibrations and stress time, the stress signal action time obtained and observation signal coincide, and vibration signal frequency is 10.17Hz, and error is 0.17Hz.
As shown in Figure 7, before carrying out temperature survey, need the k beta coefficient for thermometric multimode optical fiber in SMS optical fiber sensing system be calibrated.Its course of work is as follows: will be used for thermometric multimode optical fiber and be placed in uniform temperature water, and its temperature is linearly reduced along with water temperature, and uses thermometer measure water temperature, every 40s reads and recording thermometer reading.Carry out 6 groups of scaling experiments, as shown in Figure 7, the matched curve obtained is the calibration curve obtained
r
2=0.9941, namely calibration coefficient is k β=2.546.
As shown in Figure 8, the groundwork process of experiment is: the warm water multimode optical fiber being used for temperature sensing being placed in 70 DEG C, and fiber optic temperature declines gradually along with water temperature, and after 600s, water temperature drop is to 55 DEG C (thermometer measure values); Use sound equipment to play 10Hz audio frequency makes the SMS optical fiber vibration sensing portion shown in accompanying drawing 2 with this frequency vibration simultaneously.
As shown in Fig. 9 to Figure 12, the temperature variation signal that Fig. 9 and Figure 10 obtains after being respectively and carrying out single channel Blind Signal Separation to the mixed signal in Fig. 8 and vibration signal.The temperature variation curve that Figure 11 and Figure 12 obtains after being respectively and carrying out Hilbert conversion and FFT to Fig. 9 and Figure 10 and rumble spectrum figure.Experimental result shows, the method is when measuring vibrations and temperature linearity change at the same time, and recording temperature variation is 14.70 DEG C, and differ 0.3 DEG C with reading temperature variation 15 DEG C, error is 2%; Recording vibration frequency is 10.17Hz, differs only 0.17Hz with vibration source vibration frequency.
As shown in figure 13, the groundwork process of experiment is: the multimode optical fiber being used for temperature sensing is placed in tank, now has a small amount of temperature to be the warm water of 19.5 DEG C in tank, by pouring hot water into fast in tank, make fiber optic temperature naturally increase, final water temperature arrives 50 DEG C.Carrying out thermometric while, use sound equipment to play the audio frequency of 30Hz, make vibrating sensing optical fiber with this frequency vibration.
As shown in Figure 14 to Figure 17, in vibration with the detachment process of natural intensification signal, the data of first getting 0-50s carry out single channel blind signal processing, by isolated vibration signal as shown in figure 14, carry out FFT process, the rumble spectrum figure obtained, as shown in figure 16.Recording vibration frequency is 30.48Hz, differs only 0.48Hz with vibration source vibration frequency.Get isolated natural intensification signal temperature action part, i.e. 6-24s data, obtain the curve shown in Figure 15 after process after filtering, then carry out Hilbert conversion, obtain temperature changing curve diagram 17.Recording temperature variation is 28.13 DEG C, and differ 0.87 DEG C with reading temperature variation, error is 3.00%.
Although the foregoing describe the specific embodiment of the present invention, but those skilled in the art is to be understood that, these embodiments only illustrate, those skilled in the art, when not departing from principle of the present invention and essence, can carry out various omission, replacement and change to the details of said method and system.Such as, merge said method step, thus then belong to scope of the present invention according to the function that the method that essence is identical performs essence identical to realize the identical result of essence.Therefore, scope of the present invention is only defined by the appended claims.
Claims (4)
1. the optical fiber sensing method simultaneously measured of many reference amounts, is characterized in that comprising following steps:
Step 1) collect a road observation data from a Fibre Optical Sensor acted on by many reference amounts simultaneously;
Step 2) obtain multichannel observation data by delay sampling point;
Step 3) pre-service is carried out to the multichannel observation data obtained, pre-service comprises centralization and albefaction;
Step 4) utilize traditional blind signal separation technology, from observation signal, isolate multiple parameter;
Step 5) corresponding signal transacting is done to isolated multiple parameter, obtain the effective information of parameter;
Described corresponding signal transacting comprises:
FFT process is done to oscillating component, obtains vibration frequency information;
Hilbert conversion is done to temperature components, obtains temperature information.
2. the optical fiber sensing method simultaneously measured of a kind of many reference amounts according to claim 1, is characterized in that described step 2) specifically comprise: delay sampling point is the data array will collected in the time period, the sampling number that Late phase is corresponding.
3. the optical fiber sensing method simultaneously measured of a kind of many reference amounts according to claim 1, is characterized in that described step 3) specifically comprise: data centerization process is and makes the average of signal be zero; For stochastic variable x (t), its centralization process can be expressed as
Wherein E [x (the t)] mathematical expectation that is stochastic variable x (t); In the signal processing of reality, the length N due to the observation signal obtained by sensor measurement is limited, and the mean value of sample data can be used to replace its mathematical expectation, then formula (1) can be rewritten as
After centralization process, the object simplifying single channel Blind Signal Separation algorithm can be reached; Described whitened signal processing intent removes the correlativity between each component, makes second-order statistics between each component of the signal after albefaction independent; Right
carry out linear transformation P, obtain
Wherein R
ufor the covariance matrix of signal u (t) after albefaction, in u (t), each component is uncorrelated mutually; The main method of albefaction has three classes, is respectively principal component analysis PCA method, adaptive approach and sane whitening approach; Three kinds of methods are all applicable in the present invention, wherein only detailed descriptionthe PCA method; If
it is mean value signal
covariance matrix, namely
eigenvalues Decomposition is carried out to it, can obtain
From formula (4), we can obtain whitening matrix
P＝D
(-1/2)F
T，(5)
Wherein F is
feature matrix, D diagonal line is the diagonal matrix of eigenwert, its diagonal element λ
12, λ
22..., λ
m2for
eigenwert; Again
By formula (4), (5) are brought in formula (6), can obtain
4. the optical fiber sensing method simultaneously measured of a kind of many reference amounts according to claim 1, is characterized in that described step 4) specifically comprise:
Traditional blind signal separation technology adopts FastICA algorithm, and to maximize negentropy as objective function, isolate an independent component from observation signal, the FastICA iterative algorithm step maximum based on negentropy is as follows at every turn:
4.1) m=0 is made, initialization weight vector w (0), i.e. random selecting one initial weight vector;
4.2)m＝m+1；
4.3) w is adjusted, order
w(m+1)＝E[ug(w
T(m)u)]-E[g'(w
T(m)u)]w(m),(11)
Wherein u is mixed signal matrix, and g is nonlinear function, and w is a line in separation matrix W;
Nonlinear function need be chosen in advance;
4.4) normalized,
If algorithm is not restrained, then return 4.3);
4.5) algorithm convergence, obtains an independent component,
Wherein, y
1t () is the estimated signal of parameter corresponding to independent component,
for the original signal of parameter corresponding to independent component.
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| CN107024186A (en) * | 2017-03-24 | 2017-08-08 | 上海大学 | Ultra-thin panel interference signal method for separating and processing based on FAST ICA algorithms in wavelength phase shift |
| CN107025465A (en) * | 2017-04-22 | 2017-08-08 | 黑龙江科技大学 | Optical cable transmission underground coal mine distress signal reconstructing method and device |
| CN107621281A (en) * | 2017-08-25 | 2018-01-23 | 吴世贵 | A kind of paddy environment detects control method |
| CN108595386B (en) * | 2018-05-07 | 2022-01-25 | 长沙理工大学 | Distributed optical fiber vibration measurement method and device based on high-order cumulant analysis |
| CN110236500A (en) * | 2019-06-19 | 2019-09-17 | 深圳市矽赫科技有限公司 | Detection device for vital signs |
| CN112179475B (en) * | 2020-08-20 | 2021-09-07 | 电子科技大学 | Separation method of multi-source aliasing distributed optical fiber vibration sensing signals |
| CN112729417B (en) * | 2021-03-29 | 2021-06-22 | 湖南久钰电子有限公司 | Multi-parameter intelligent monitoring system and method based on perception data fusion |
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