CN111157116A - Underwater Brillouin scattering spectrum test system - Google Patents
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Abstract
The invention discloses an underwater Brillouin scattering spectrum testing system, which comprises: the band elimination filter is used for carrying out filtering processing on the passed Brillouin scattering light to obtain the Brillouin scattering light after noise is removed; a first edge filter for receiving the noise-removed brillouin scattered light, passing first scattered light of the brillouin scattered light, and obtaining reflected first reflected light; a first light energy detection device for detecting a first energy value in the first scattered light; the second edge filter is used for receiving the first scattered light, passing through second scattered light in the first scattered light and obtaining second reflected light after reflection; a second light energy detection means for detecting a second energy value in the second scattered light; and the third light energy detection device is used for detecting the residual energy value of the second reflected light. The system can realize the real-time stable acquisition of the Brillouin scattering spectrum.
Description
Technical Field
The invention relates to the technical field of computers, in particular to an underwater Brillouin scattering spectrum testing system.
Background
Brillouin laser radar is a new ocean remote sensing detection technology, and inversion of environmental parameters such as ocean sound velocity, temperature and salinity and detection of underwater targets can be realized by measuring characteristic parameters such as frequency shift and line width in seawater Brillouin scattering spectrum.
At first, the traditional scanning interferometer technology is adopted to measure the Brillouin scattering spectrum, the scanning interferometer technology can accurately acquire the scattering spectrum, but light which needs to be incident to the interferometer needs to be strictly collimated, which is difficult in actual environment; in addition, a certain time is needed for scanning, real-time and rapid measurement of the scattering spectrum cannot be achieved, and practical application is limited. The edge detection technique uses a molecular absorption cell as an edge filter, and performs the inversion of the brillouin frequency shift by detecting the energy change transmitted through the filter. However, the current edge detection technology cannot achieve the acquisition of the brillouin line and the whole scattering spectrum, and further cannot adjust the measurement range. Although the F-P standard combined ICCD detection method can realize measurement of the whole Brillouin scattering spectrum, the method is limited by the existing integration time limit of ICCD and cannot realize acquisition of the real-time Brillouin scattering spectrum of the vertical whole profile.
Therefore, there is an urgent need for a device capable of realizing real-time and stable acquisition of brillouin scattering spectra.
Disclosure of Invention
In view of the above problems, the present invention provides an underwater brillouin scattering spectrum testing system, which can realize real-time stable acquisition of brillouin scattering spectrum.
The technical scheme provided by the application through one embodiment is as follows:
an underwater brillouin scattering spectroscopy test system comprising:
the band elimination filter is used for carrying out filtering processing on the passed Brillouin scattering light to obtain the Brillouin scattering light after noise is removed;
a first edge filter for receiving the noise-removed brillouin scattered light, passing first scattered light of the brillouin scattered light, and obtaining reflected first reflected light;
a first light energy detection device for receiving the first scattered light and detecting a first energy value in the first scattered light; wherein the first energy value comprises a frequency shift characteristic and a line width characteristic of the Brillouin scattering light;
the second edge filter is used for receiving the first scattered light, passing through second scattered light in the first scattered light and obtaining second reflected light after reflection;
a second light energy detection device for receiving the second scattered light and detecting a second energy value in the second scattered light; wherein the second energy value comprises a frequency shift characteristic and a line width characteristic of the brillouin light;
third light energy detection means for receiving the second reflected light and detecting the remaining energy value of the second reflected light;
obtaining the spectral frequency shift and the spectral line width of the Brillouin scattering light through the first energy value, the second energy value and the residual energy value; and carrying out inversion according to the spectral frequency shift and the spectral linewidth to obtain the spectrum of the Brillouin scattering light.
Preferably, the method further comprises the following steps: a laser; the laser is used for emitting laser to a target water area to be detected and generating backward Rayleigh Brillouin scattering light; the band rejection filter is specifically configured to receive the backward rayleigh brillouin scattered light.
Preferably, the laser is a low pulse energy high repetition rate laser.
Preferably, the parameters of the band-stop filter include: the spectral frequency offset is 0, and the full width at half maximum of the spectrum is 4.4; the free spectral range is 20.
Preferably, the parameters of the first edge filter include: the spectral frequency offset is 5.5, the full width at half height of the spectrum is 0.4, and the free spectral range is 10.1.
Preferably, the parameters of the second edge filter include: the spectral frequency offset is 9.3, the full width at half height of the spectrum is 0.4, and the free spectral range is 18.6.
Preferably, the first edge filter and the second edge filter are both F-P interferometers.
Preferably, the transfer function of the first edge filter and the second edge filter is
Wherein, TiAs a transfer function, FSRiIs the free spectral range, Γ, of the ith edge filteriIs the full width at half maximum of the ith edge filter, v is the frequency, and i is 1 or 2.
Preferably, the method is applied to water areas with the temperature of less than or equal to 20 ℃.
Preferably, the method is applied to water areas with the temperature of less than or equal to 10 ℃.
The underwater Brillouin scattering spectrum test system provided by the embodiment of the invention comprises: the band elimination filter is used for carrying out filtering processing on the passing Brillouin scattering light to obtain the Brillouin scattering light after noise is removed; a first edge filter for receiving the noise-removed brillouin scattered light, passing first scattered light of the brillouin scattered light, and obtaining reflected first reflected light; first light energy detection means for detecting a first energy value in the first scattered light; the first energy value comprises frequency shift characteristics and line width characteristics of the Brillouin scattering light; the second edge filter is used for receiving the first scattered light, passing through second scattered light in the first scattered light and obtaining second reflected light after reflection; a second light energy detection device for detecting a second energy value in the second scattered light; wherein the second energy value comprises a frequency shift characteristic and a line width characteristic of the brillouin scattering light; third light energy detection means for detecting a residual energy value of the second reflected light; finally, the spectral frequency shift and the spectral line width of the Brillouin scattering light can be obtained according to the first energy value, the second energy value and the residual energy value measured by the system; and performing reverse operation according to the spectral frequency shift and the spectral line width to obtain the spectrum of the Brillouin scattering light in real time. The system expands the measurement function of the edge detection technology, realizes the measurement of the whole Brillouin spectrum, can measure and acquire the spectral frequency shift and the spectral line width of Brillouin scattered light, has good timeliness and stability, and can be applied to the remote sensing of environmental elements such as temperature, salinity and the like of a laser radar.
The foregoing description is only an overview of the technical solutions of the present invention, and the embodiments of the present invention are described below in order to make the technical means of the present invention more clearly understood and to make the above and other objects, features, and advantages of the present invention more clearly understandable.
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Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:
fig. 1 shows a schematic structural diagram of an underwater brillouin scattering spectrum testing system according to a first embodiment of the present invention;
fig. 2 shows a flow chart of a method for acquiring an underwater brillouin scattering spectrum according to a second embodiment of the present invention;
FIG. 3 is a diagram showing a spectral frequency shift and a spectral line width as inversion results of two energy ratios of a first edge filter and a second edge filter according to a second embodiment of the present invention;
fig. 4 shows a functional block diagram of an underwater brillouin scattering spectrum acquisition device according to a third embodiment of the present invention.
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
First embodiment
Referring to fig. 1, fig. 1 shows a schematic structural diagram of an underwater brillouin scattering spectroscopy test system 100 in this embodiment, where the system 100 includes: a band stop filter 11, a first edge filter 21, a first light energy detection device 31, a second edge filter 22, a second light energy detection device 32 and a third light energy detection device 33. The matching relation and the action of the structures are as follows:
the band elimination filter 11 is used for performing filtering processing on the passed Brillouin scattering light to obtain the Brillouin scattering light after noise is removed;
a first edge filter 21 configured to receive the brillouin scattered light from which noise is removed, pass first scattered light of the brillouin scattered light, and obtain reflected first reflected light;
a first light energy detection device 31 for receiving the first scattered light and detecting a first energy value in the first scattered light; wherein the first energy value comprises a frequency shift characteristic and a line width characteristic of the Brillouin scattering light;
a second edge filter 22, configured to receive the first scattered light, pass through a second scattered light of the first scattered light, and obtain a second reflected light after reflection;
a second light energy detection device 32 for receiving the second scattered light and detecting a second energy value in the second scattered light; wherein the second energy value comprises a frequency shift characteristic and a line width characteristic of the brillouin light.
Third light energy detection means 33 for receiving said second reflected light and detecting the remaining energy value of said second reflected light.
The energy passing through the first edge filter 21 and the second edge filter 22 is different under different line widths and frequency shifts theoretically by the system 100, so that the frequency shift and the line width can be measured by the frequency shift characteristic and the line width characteristic energy, that is, the spectral frequency shift and the spectral line width of the brillouin scattering light can be obtained according to the first energy value, the second energy value and the residual energy value measured by the system; and performing inversion according to the spectrum frequency shift and the spectrum line width to obtain the spectrum of the Brillouin scattering light in real time.
In order to generate scattered light which is easy to measure and improve the accuracy of the system 100 in measuring the line width characteristic and the frequency shift characteristic, the system 100 in this embodiment further includes a laser, which is used for emitting laser to a target water area to be measured and generating backward rayleigh brillouin scattered light; the band rejection filter 11 is also specifically configured to receive backward rayleigh brillouin scattered light. And preferably the laser is a low pulse energy high repetition rate laser.
In the present system 100, the backward rayleigh brillouin scattered light may be received through a telescope; in addition, the optical path between the filters can be changed by the mirror 41, and the arrangement of the mirror 41 is not limited.
The first light energy detecting device 31, the second light energy detecting device 32, and the third light energy detecting device 33 may be each a PMT (photomultiplier tube).
Since it is necessary to ensure that the brillouin scattered light has enough energy to be received by the three detection devices in the system 100, it is very important to set parameters of the band stop filter 11 and the two edge filters, so as to ensure that the edge filters are sensitive to the spectral change of the brillouin scattered light, and ensure that the energy received by the PMT is as strong as possible, thereby facilitating detection. The following parameter settings are adopted in this embodiment:
the parameters of the band-stop filter 11 include: the spectral frequency offset is 0, the spectral full width at half maximum is 4.4, and the free spectral range is 20.
The first edge filter 21 and the second edge filter 22 may be F-P (Fabry-Perot) interferometers. This time is:
the parameters of the first edge filter 21 include: the spectral frequency offset is 5.5, the full width at half maximum of the spectrum is 0.4, and the free spectral range is 10.1, so that the line width characteristic of the Brillouin scattering light spectrum is extracted. The parameters of the second edge filter 22 include: the spectral frequency offset was 9.3, the spectral full width at half maximum was 0.4, and the free spectral range was 18.6. At the same time, the transfer function of the F-P interferometer can be determined as
Wherein, TiAs a transfer function, FSRiIs the free spectral range, Γ, of the ith edge filteriIs the full width at half maximum of the ith edge filter, v is the frequency, i is 1 or 2 (first edge filter 21 or second edge filter 22).
The system 100 of the present embodiment is preferably applicable to water with a temperature of 20 ℃ or less, and more particularly, to water with a temperature of 10 ℃ or less, and the detailed description will be continued with reference to the second embodiment described later.
The system 100 in this embodiment expands the measurement function of the edge detection technology, and can obtain the spectral frequency shift and the spectral line width of the brillouin scattering light according to the first energy value, the second energy value, and the remaining energy value measured by the system; and performing inversion according to the spectral frequency shift and the spectral line width to obtain the spectrum of the Brillouin scattering light in real time, thereby realizing the measurement of the whole Brillouin spectrum. The system 100 in the implementation can be used for measuring and acquiring the spectral frequency shift and the spectral line width of the Brillouin scattered light in real time, has good timeliness and stability, and can be applied to the remote sensing of environmental elements such as temperature, salinity and the like of the laser radar.
It should be noted that the detailed process and the description of the specific application scenario for inverting the brillouin scattering light spectrum based on the system 100 in the present embodiment can be referred to the contents set forth in the second embodiment.
Second embodiment
Referring to fig. 2, fig. 2 is a flowchart illustrating a method for acquiring an underwater brillouin scattering spectrum according to the present embodiment, where the method may use parameters measured by the system in the first embodiment, and the method includes:
step S10: acquiring a first energy value of first scattered light obtained after Brillouin scattered light passes through a first edge filter; and obtaining first reflected light that does not pass through the first edge filter; wherein the first energy value comprises a frequency shift characteristic and a line width characteristic of the brillouin light;
step S20: acquiring a second energy value of second scattered light obtained after the first reflected light passes through a second edge filter; and obtaining second reflected light that has not passed through the second edge filter; wherein the second energy value comprises a frequency shift characteristic and a frequency shift characteristic of the brillouin scattering light and a line width characteristic;
step S30: acquiring a residual energy value of the second reflected light;
step S40: obtaining the spectral frequency shift and the spectral line width of the Brillouin scattering light according to the first energy value, the transfer function of the first edge filter, the second energy value, the transfer function of the second edge filter and the residual energy value;
step S50: and carrying out inversion according to the spectral frequency shift and the spectral line width to obtain the spectrum of the Brillouin scattering light.
It should be noted that, before step S10, a denoising step may be performed, which is referred to as bottom noise interference. The method specifically comprises the following steps: and filtering the Brillouin scattering light through a band elimination filter to obtain the acquired Brillouin scattering light after noise is removed.
The brillouin scattering light spectrum after passing through the band-stop filter can be expressed as:
wherein, IB(vB,ΓB) For de-noised Brillouin scattering light spectrum after passing through a band-stop filter, vBFor Brillouin scattering spectral frequency deviation, gammaBFor the full width at half maximum of the brillouin scattering light spectrum (same spectral line width in this document, the same applies hereinafter), v is the frequency.
In steps S10-S30, the first energy value, the second energy value and the remaining energy value may be obtained from respective measuring devices, for example, the corresponding first light energy detecting device, the second light energy detecting device and the third light energy detecting device in the first embodiment.
Specifically, in this embodiment, the first energy value is expressed in the following manner, and the spectral frequency shift and the spectral line width are introduced:
wherein, IB(vB,ΓB) Is a Brillouin scattering light spectrum, I1Is a first energy value, T1Being the transfer function of the first edge filter, Γ1Is the full width at half maximum of the first edge filter, v is the frequency, vBFor Brillouin scattering spectral frequency deviation, gammaBIs the full width at half maximum of the brillouin scattering spectrum.
The second energy value is expressed in the following way, and the spectral frequency shift and the spectral line width are introduced:
wherein, I2Is a second energy value, T2Is the transfer function of the second edge filter, Γ2Is the full width at half maximum of the second edge filter, v is the frequency, vBFrequency deviation of Brillouin scattering spectrum, gammaBIs the full width at half maximum of the brillouin scattering spectrum.
In this embodiment, an F-P interferometer is used as the edge filter, so the transfer function Ti' given in Airy function, specifically:
wherein, TiAs a transfer function, FSRiIs the free spectral range, Γ, of the ith edge filteriThe full width at half maximum of the ith edge filter, v the frequency, i ═ 1 or 2 (first edge filter or second edge filter).
The residual energy value is expressed as follows:
further, in order to eliminate the instability of energy reception, the relative energy value is used as the actual measurement signal in the embodiment, so that the accuracy of the energy value is improved.
That is, the step of determining the spectral frequency shift and the spectral line width in step S40 may include the following steps:
step S41: obtaining a first relative energy according to the ratio of the first energy value to the residual energy value;
step S42: obtaining a second relative energy according to the ratio of the second energy value to the residual energy value;
step S43: obtaining the spectral frequency shift and the spectral line width according to the first relative energy, the second relative energy, the transfer function of the first edge filter, and the transfer function of the second edge filter.
In steps S41-S42, the first energy value I1And a second energy value I2Respectively with the residual energy value IgThe ratio is carried out to obtain the relative energy S1And S2The following are:
wherein S is1Is a first relative energy, S2For the second relative energy, the instability between the first energy value and the second energy value is eliminated by the above process.
In step S43, since the first relative energy is known, the secondThe spectral frequency shift v of the Brillouin reflection spectrum can be obtained by two relative energies, the transfer function of the first edge filter and the transfer function of the second edge filterB(S1,S2) And spectral linewidth ΓB(S1,S2)。
The energy transmitted through the two edge filters under different spectral line widths and spectral frequency shift conditions is different, so that the frequency shift and the line width can be measured through the two characteristic energies. Finally, step S50 is executed, since the brillouin scattering light spectrum of seawater follows the form of lorentzian function, there are:
wherein, f (v, v)B) Is a Brillouin scattering light spectrum, vBFor spectral frequency shifting, ΓBIs the spectral linewidth and v is the frequency. And obtaining a final Brillouin scattering light spectrum according to the inversion model.
In this embodiment, it is ensured that the edge filter is not only sensitive enough to the spectral change of the brillouin scattering light, but also the data accuracy of the detected first energy value, second energy value and residual energy value is ensured. In this embodiment, based on the actual brillouin spectral characteristics in seawater, the edge filter parameters are optimized by a computer traversal method, and a better setting scheme of the band-stop filter, the first edge filter, and the second edge filter can be obtained, specifically as follows:
TABLE 1 Filter parameter settings when data is acquired
| vi/GHz | Γi/GHz | FSR/GHz | |
| First edge filter | 5.5 | 0.4 | 10.1 |
| First edge filter | 9.3 | 0.4 | 18.6 |
| Band elimination filter | 0.0 | 4.4 | 20 |
Further, a description is given to the underwater brillouin scattering spectrum acquisition method according to the present invention by using specific examples, which specifically include the following steps:
based on the parameters in table 1, the inversion model will be constructed by means of simulation using a numerical fitting program. The first step is to obtain the first and second relative energies S under different spectral frequency shifts and spectral line widths based on a theoretical formula1And S2As shown in tables 2 and 3 below.
TABLE 2 different spectral frequency shifts VBAnd spectral linewidth ΓBNormalized energy E of first edge filter under1(10-2)
TABLE 3 different spectral frequency shifts VBAnd spectral linewidth ΓBNormalized energy E of the second edge filter2(10-2)
Tables 2 and 3 show two sets of three-dimensional data: (S)1,S2,VB) And (S)1,S2，ΓB). The two sets of data are used as sample points, and the results are shown in fig. 3 (where a is the spectrum frequency shift as the inversion result of the two energy ratio values of the first and second edge filters, and B is the spectrum line width as the inversion result of the two energy ratio values of the first and second edge filters) by performing empirical formula fitting of frequency shift and line width according to the least square method. The specific sum model after the fitting is completed is:
VB(S1,S2)＝r1+r2S1+r3S2+r4(S1)2+r5(S2)2+r6S1S2+r7(S1)3
+r8(S2)3+r9S1(S2)2+r10(S1)2S2
ΓB(S1,S2)＝t1+t2S1+t3S2+t4(S1)2+t5(S2)2+t6S1S2+t7(S1)3
+t8(S2)3+t9S1(S2)2+t10(S1)2S2
wherein, gamma isBAnd VBIn units of GHz, r1～r10And t1～t10For fitting parameters, please refer to other parametersWith reference to the foregoing description, further description is omitted. The fitting parameters are specifically as follows:
TABLE 4 r1～r10Value of (2)
| r1＝7.68953×103 | r2＝4.54470×103 |
| r3＝-4.32826×103 | r4＝1.00227×103 |
| r5＝-9.91561×102 | r6＝4.44217×101 |
| r7＝4.72354×101 | r8＝-4.80650×101 |
| r9＝-1.07892×102 | r10＝1.13459×102 |
TABLE 5 t1～t10Value of (2)
| t1＝-5.65539×102 | t2＝3.75370×104 |
| t3＝3.77333×104 | t4＝-8.08552×105 |
| t5＝-8.15555×105 | t6＝2.29871×105 |
| t7＝4.38531×106 | t8＝4.35425×106 |
| t9＝9.52144×106 | t10＝8.76976×106 |
Based on the model, the spectral frequency shift and the spectral line width can be synchronously inverted through the characteristic energy obtained by the double-edge detection technology.
Further, in this embodiment, robustness of the method is verified, and an optimal usage environment is determined. The method comprises the following specific steps:
by analyzing the fitting error, the accuracy and robustness of the empirical function are calculated, and the spectral frequency shift and the sensitivity of the spectral line width obtained by the model are estimated.
Since the above-mentioned inversion model is an empirical formula obtained by fitting according to actual simulation data, an error between the empirical formula and the actual simulation data is first analyzed to evaluate a degree of conformity of the empirical formula. Fitting model V to frequency shift by empirical formulaB(E1,E2) And line width fitting model gammaB(E2,E2) Comparing the calculated values with the data in tables 1 and 2, the spectral frequency shift obtained by the double-edge filtering formed by the first and second edge filters can be obtainedThe maximum error of (2) is +/-4 MHz, most of errors of the full width at half maximum are distributed at +/-6 MHz, and the errors are divided into +/-12 MHz points. These errors are within acceptable ranges when measuring the brillouin reflected light spectral shift and spectral linewidth.
Further, the sensitivity and dependence of the model on frequency shift and line width measurements are analyzed. The frequency shift and the line width are theoretically independent of each other, and their values in the inverse model are determined only by the measured first energy value, the second energy value, and the residual energy value of the edge filter. Sensitivity of the inverse model, i.e. energy ratio S1、S2Can cause spectral frequency shifts and changes in spectral linewidths. Using model V at the fittingB(S1,S2) And ΓB(S1,S2) The change in spectral frequency shift caused by the first edge filter measurement can be expressed as:
wherein the content of the first and second substances,
sequentially comprises the following steps:
assuming that the minimum resolution of the edge filter to the energy value is 0.01%, the energy jitter Δ S is 1 × 10-4Then the sensitivity can be expressed as
Specifically, error analysis is carried out under the conditions that the temperature is 0-30 ℃ and the salinity is 0-35 per mill, and errors caused by energy jitter can be obtained:
TABLE 6
And
comparison (S)1:1％-5％；S2:1％-5％)
TABLE 7
And
comparison (S)1:1％-5％；S2:1％-5％)
It can be seen from tables 6 and 7 that each 0.01 jitter in received energy brings about an average error of 6MHz in the brillouin line width. This value is much larger than the error of the brillouin frequency shift of less than 1 MHz.
Further, when temperature and salinity synchronous inversion is carried out according to the spectral frequency shift and the spectral line width, the accuracy of the final inversion result is analyzed. The error condition caused by the change of temperature and salinity can be obtained:
TABLE 8 inversion error of frequency shift sensitivity versus temperature salinity
TABLE 9 inversion error of linewidth sensitivity to temperature and salinity
As can be seen from tables 8 and 9, when the brillouin scattering spectrum is inverted by adopting the double-edge detection technology to invert the seawater temperature and salinity, the average errors of the spectral frequency shift to the temperature and the salinity are respectively 0.1 ℃ and 0.1 psu; the average error of the line width to the temperature is 0.3 ℃, the average error to the salinity is 0.5 ℃, and the maximum errors respectively reach 0.6 ℃ and 1.0 psu. It can also be seen that the instability of the measured energy has a large influence on the spectral linewidth and is further reflected on the final measurement accuracy of temperature and salinity.
Analyzing the reasons of the errors, wherein the Brillouin spectral frequency shift is the highest point of a scattering peak and has obvious characteristics for identification; the brillouin spectral line width depends on the shape of the whole spectral line, and the brillouin spectral line width is increased or reduced by a little, so that the change caused by energy is not as sensitive as the change of the frequency shift of the whole spectral line, and the measurement error of the brillouin spectral line width is relatively large. According to the inversion process of the Brillouin scattering light in the embodiment, when the temperature of seawater is lower and is about 10 ℃, the influence of the spectral line width error on temperature and salt measurement is small; when the temperature is about 30 ℃, the influence of the spectral line width error on the measurement is large, and the influence of the spectral frequency shift on the measurement is small. According to further analysis of the inversion process of the brillouin scattering light in the embodiment, when the temperature of the seawater is not more than 20 ℃, the inversion seawater temperature error of the method in the embodiment is 0.2 ℃, the salinity error is 0.5 per thousand, and the measurement precision is higher. When the temperature is higher than 20 ℃, the error of the temperature and the salinity will be increased, the error of the temperature can be as large as 0.6 ℃, and the error of the salinity can be as large as 1 per thousand. Thereby the measurement accuracy is higher at low temperatures. It can be seen that the preferable application environment in this embodiment is an environment in a water area of 30 ℃ or less, and more preferably an environment in a water area of 20 ℃ or less.
In summary, in the method for acquiring an underwater brillouin scattering spectrum provided in this embodiment, a first energy value of first scattered light obtained after brillouin scattered light passes through a first edge filter is acquired; acquiring a second energy value of second scattered light obtained after the first reflected light passes through a second edge filter; acquiring a residual energy value of the second reflected light; then, according to the first energy value, the transfer function of the first edge filter, the second energy value, the transfer function of the second edge filter and the residual energy value, the spectral frequency shift and the spectral line width of the brillouin scattering light can be obtained at the same time, and finally, the spectrum of the brillouin scattering light is obtained through inversion of the spectral frequency shift and the spectral line width. The method has the advantages that the first energy value, the second energy value and the residual energy value can be obtained in real time in the whole process, good real-time performance is achieved, the frequency domain and the line width of the Brillouin scattering can be simultaneously inverted by obtaining the two edge energies, and the whole Brillouin scattering light spectrum is reconstructed through the first energy value, the second energy value and the residual energy value, so that the method has high inversion precision and stability and low environmental limit.
Third embodiment
Referring to fig. 4, based on the same inventive concept, in this embodiment, there is also provided an underwater brillouin scattering spectrum acquisition apparatus 300, where the apparatus 300 includes:
the first energy value acquiring module 301 is configured to acquire a first energy value of first scattered light obtained after the brillouin scattered light passes through a first edge filter; and obtaining first reflected light that does not pass through the first edge filter; wherein the first energy value comprises a frequency shift characteristic and a line width characteristic of the brillouin light;
a second energy value obtaining module 302, configured to obtain a second energy value of second scattered light obtained after the first reflected light passes through a second edge filter; and obtaining second reflected light that has not passed through the second edge filter; wherein the second energy value comprises a frequency shift characteristic and a line width characteristic of the brillouin light;
a residual energy value acquiring module 303, configured to acquire a residual energy value of the second reflected light;
a frequency shift and line width obtaining module 304, configured to obtain a spectral frequency shift and a spectral line width of the brillouin scattering light according to the first energy value, the transfer function of the first edge filter, the second energy value, the transfer function of the second edge filter, and the residual energy value;
a spectrum obtaining module 305, configured to perform inversion according to the spectrum frequency shift and the spectrum line width, so as to obtain a spectrum of the brillouin scattering light.
Preferably, the frequency shift and line width obtaining module 304 is further specifically configured to:
obtaining a first relative energy according to the ratio of the first energy value to the residual energy value;
obtaining a second relative energy according to the ratio of the second energy value to the residual energy value;
and obtaining the spectral frequency shift and the spectral line width according to the first relative energy, the second relative energy, the transfer function of the first edge filter and the transfer function of the second edge filter.
It should be noted that the implementation and technical effects of the underwater brillouin scattering spectrum acquisition device 300 provided in the embodiment of the present invention are the same as those of the foregoing method embodiment, and for the sake of brief description, reference may be made to corresponding contents in the foregoing method embodiment to the extent that no part of the embodiment of the device is mentioned.
Fourth embodiment
Further, based on the same inventive concept, a fourth embodiment of the present invention further provides an underwater brillouin scattering spectrum acquisition apparatus, including a processor and a memory, the memory being coupled to the processor, the memory storing instructions that, when executed by the processor, cause the user terminal to perform the following operations:
acquiring a first energy value of first scattered light obtained after Brillouin scattered light passes through a first edge filter; and obtaining first reflected light that does not pass through the first edge filter; wherein the first energy value comprises a frequency shift characteristic and a line width characteristic of the brillouin light; obtaining a second energy value of second scattered light obtained after the first reflected light passes through a second edge filter; and obtaining second reflected light that has not passed through the second edge filter; wherein the second energy value comprises a frequency shift characteristic and a line width characteristic of the brillouin scattering light; acquiring a residual energy value of the second reflected light; obtaining the spectral frequency shift and the spectral line width of the brillouin scattering light according to the first energy value, the transfer function of the first edge filter, the second energy value, the transfer function of the second edge filter and the residual energy value; and carrying out inversion according to the spectral frequency shift and the spectral line width to obtain the spectrum of the Brillouin scattering light.
It should be noted that, the implementation steps and the resulting technical effects of the underwater brillouin scattering spectrum acquisition apparatus provided in the embodiment of the present invention are the same as those of the foregoing method embodiment, and for the sake of brief description, corresponding contents in the foregoing method embodiment may be referred to for parts that are not mentioned in the apparatus embodiment.
The function modules integrated with the device provided by the invention can be stored in a computer readable storage medium if the function modules are realized in the form of software function modules and sold or used as independent products. Based on such understanding, all or part of the flow of the method of implementing the above embodiments may also be implemented by instructing the relevant hardware through a computer program, which may be stored in a computer readable storage medium, and when the computer program is executed by a processor, the steps of the above method embodiments may be implemented. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, an executable file or some intermediate form, etc. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, usb disk, removable hard disk, magnetic disk, optical disk, computer Memory, Read-Only Memory (ROM), Random Access Memory (RAM), electrical carrier wave signals, telecommunications signals, software distribution medium, etc. It should be noted that the computer readable medium may contain content that is subject to appropriate increase or decrease as required by legislation and patent practice in jurisdictions, for example, in some jurisdictions, computer readable media does not include electrical carrier signals and telecommunications signals as is required by legislation and patent practice.
The algorithms and displays presented herein are not inherently related to any particular computer, virtual machine, or other apparatus. Various general purpose systems may also be used with the teachings herein. The required structure for constructing such a system will be apparent from the description provided above. Moreover, the present invention is not directed to any particular programming language. It is appreciated that a variety of programming languages may be used to implement the teachings of the present invention as described herein, and any descriptions of specific languages are provided above to disclose the best mode of the invention.
In the description provided herein, numerous specific details are set forth. It is understood, however, that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.
Similarly, it should be appreciated that in the foregoing description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. However, the disclosed method should not be interpreted as reflecting an intention that: that the invention as claimed requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.
Those skilled in the art will appreciate that the modules in the device in the embodiments may be adaptively changed and disposed in one or more devices different from the embodiments. The modules or units or components in the embodiments may be combined into one module or unit or component and furthermore may be divided into a plurality of sub-modules or sub-units or sub-components. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and all of the processes or elements of any method or apparatus so disclosed, may be combined in any combination, except combinations where at least some of such features and/or processes or elements are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.
Furthermore, those skilled in the art will appreciate that while some embodiments herein include some features included in other embodiments, rather than others, combinations of features of different embodiments are meant to be within the scope of the invention and form different embodiments. For example, in the following claims, any of the claimed embodiments may be used in any combination.
The various component embodiments of the invention may be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. Those skilled in the art will appreciate that a microprocessor or Digital Signal Processor (DSP) may be used in practice to implement some or all of the functionality of some or all of the components in an apparatus according to an embodiment of the invention. The present invention may also be embodied as apparatus or device programs (e.g., computer programs and computer program products) for performing a portion or all of the methods described herein. Such a program implementing the invention may be stored on a computer readable medium or may be in the form of one or more signals. Such a signal may be downloaded from an internet website or provided on a carrier signal or in any other form.
It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by one and the same item of hardware. The usage of the words first, second and third, etcetera do not indicate any ordering. These words may be interpreted as names.
Claims (10)
1. An underwater brillouin scattering spectroscopy test system, comprising:
the band elimination filter is used for carrying out filtering processing on the passed Brillouin scattering light to obtain the Brillouin scattering light after noise is removed;
a first edge filter for receiving the noise-removed brillouin scattered light, passing first scattered light of the brillouin scattered light, and obtaining reflected first reflected light;
a first light energy detection device for receiving the first scattered light and detecting a first energy value in the first scattered light; wherein the first energy value comprises a frequency shift characteristic and a line width characteristic of the Brillouin scattering light;
the second edge filter is used for receiving the first scattered light, passing through second scattered light in the first scattered light and obtaining second reflected light after reflection;
a second light energy detection device for receiving the second scattered light and detecting a second energy value in the second scattered light; wherein the second energy value comprises a frequency shift characteristic and a line width characteristic of the brillouin light;
and the third light energy detection device is used for receiving the second reflected light and detecting the residual energy value of the second reflected light.
2. The system of claim 1, further comprising:
a laser; the laser is used for emitting laser to a target water area to be detected and generating backward Rayleigh Brillouin scattering light;
the band rejection filter is specifically configured to receive the backward rayleigh brillouin scattered light.
3. The system of claim 2, wherein the laser is a low pulse energy high repetition rate laser.
4. The system of claim 1, wherein the parameters of the band-stop filter comprise: the spectral frequency offset is 0, and the full width at half maximum of the spectrum is 4.4; the free spectral range is 20.
5. The system of claim 1, wherein the parameters of the first edge filter comprise: the spectral frequency offset was 5.5, the full width at half maximum of the spectrum was 0.4, and the free spectral range was 10.1.
6. The system of claim 1, wherein the parameters of the second edge filter comprise: the spectral frequency offset was 9.3, the spectral full width at half maximum was 0.4, and the free spectral range was 18.6.
7. The system of claim 1, wherein the first edge filter and the second edge filter are both F-P interferometers.
8. The system of claim 7, wherein the transfer function of the first edge filter and the second edge filter is
Wherein the content of the first and second substances,Tias a transfer function, FSRiIs the free spectral range, Γ, of the ith edge filteriIs the full width at half maximum of the ith edge filter, v is the frequency, and i is 1 or 2.
9. The system of claim 1, wherein the system is applied to a body of water having a temperature of 20 ℃ or less.
10. The system of claim 9, wherein the system is applied to a body of water having a temperature of 10 ℃ or less.
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2676502Y (en) * | 2004-03-08 | 2005-02-02 | 武汉光迅科技有限责任公司 | Three-port single-fiber bidirectional device |
| CN102620857A (en) * | 2012-03-27 | 2012-08-01 | 南京大学 | Brillouin optical time domain reflectometer for single-photon detection based on edged filter method |
| CN103261857A (en) * | 2010-12-21 | 2013-08-21 | 堀场乔宾伊冯公司 | Device and method for observing and for measuring Raman scattering |
| CN105890797A (en) * | 2016-05-19 | 2016-08-24 | 中国科学技术大学 | High-spectral Rayleigh-Brillouin optical time-domain reflectometer capable of simultaneously detecting temperature and stress |
| US20170149551A1 (en) * | 2015-11-20 | 2017-05-25 | Honeywell International Inc. | Systems and methods for radio frequency energy multiplexers |
| CN108088482A (en) * | 2017-11-30 | 2018-05-29 | 华中科技大学鄂州工业技术研究院 | A kind of two-parameter method for synchronously measuring of atmospheric environment and system |
| CN109142278A (en) * | 2018-09-14 | 2019-01-04 | 华北电力大学（保定） | A kind of measurement method of seawater salinity |
| US20190353577A1 (en) * | 2018-05-21 | 2019-11-21 | Cytek Biosciences, Inc. | Fast recompensation of flow cytometery data for spillover readjustments |
-
2019
- 2019-12-18 CN CN201911309033.3A patent/CN111157116B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2676502Y (en) * | 2004-03-08 | 2005-02-02 | 武汉光迅科技有限责任公司 | Three-port single-fiber bidirectional device |
| CN103261857A (en) * | 2010-12-21 | 2013-08-21 | 堀场乔宾伊冯公司 | Device and method for observing and for measuring Raman scattering |
| CN102620857A (en) * | 2012-03-27 | 2012-08-01 | 南京大学 | Brillouin optical time domain reflectometer for single-photon detection based on edged filter method |
| US20170149551A1 (en) * | 2015-11-20 | 2017-05-25 | Honeywell International Inc. | Systems and methods for radio frequency energy multiplexers |
| CN105890797A (en) * | 2016-05-19 | 2016-08-24 | 中国科学技术大学 | High-spectral Rayleigh-Brillouin optical time-domain reflectometer capable of simultaneously detecting temperature and stress |
| CN108088482A (en) * | 2017-11-30 | 2018-05-29 | 华中科技大学鄂州工业技术研究院 | A kind of two-parameter method for synchronously measuring of atmospheric environment and system |
| US20190353577A1 (en) * | 2018-05-21 | 2019-11-21 | Cytek Biosciences, Inc. | Fast recompensation of flow cytometery data for spillover readjustments |
| CN109142278A (en) * | 2018-09-14 | 2019-01-04 | 华北电力大学（保定） | A kind of measurement method of seawater salinity |
Non-Patent Citations (1)
| Title |
|---|
| 戴瑞 等: "基于布里渊散射的水下目标探测", 《激光与光电子学进展》 * |
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