CN104316160B - Underwater signal instantaneous frequency demodulation method based on Wavelet Ridge - Google Patents
Underwater signal instantaneous frequency demodulation method based on Wavelet Ridge Download PDFInfo
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Abstract
Based on the underwater signal instantaneous frequency demodulation method of Wavelet Ridge, it is related to the demodulation of underwater signal instantaneous frequency, belongs to underwater signal Detection Techniques field.The signal demodulating method that the present invention solves existing routine is frequency spectrum analysis method, and frequency spectrum analysis method not can determine that the instantaneous frequency of underwater signal；Calculate underwater signal frequency when, the detection accuracy of frequency is depended on the setting of frequency spectrum threshold value, the problem of gross error usually occurs.The technical scheme is that：Wavelet conversion coefficient is obtained to signal wavelet transformation；Obtain the distributing position of each moment small echo ridge point according to local model maximum value method；Calculate the Wavelet Ridge center yardstick in each moment according to the distributing position of small echo ridge point；Instantaneous frequency according to wavelet center yardstick each moment of reverse.The suitable application area of the present invention：The detection of audible target audible frequency under water, liquid surface frequency of sound wave detect, the measurement of small amplitude mechanical oscillation frequencies.
Description
Technical field
The present invention relates to the demodulation of underwater signal instantaneous frequency, more particularly, to a kind of underwater signal based on Wavelet Ridge
Instantaneous frequency demodulation method, belongs to underwater signal Detection Techniques field.
Background technology
The outside radiative acoustic wave of underwater sound source, can form the water surface sound wave of horizontal transmission in water surface, water surface sound wave
Frequency of vibration is consistent with the audible frequency of underwater sound source, and therefore water surface sound wave carries the relevant information of underwater signal.Cause
This, due to the needs of Underwater Target Detection, increasingly pay attention to the detection to water surface sound wave and utilization.Laser interference method can
Obtain the frequency information of underwater signal from dynamic water surface, detect water surface sound wave using laser interference to obtain under water
The information of acoustical signal is increasingly becoming study hotspot.Become acquisition water currently with laser doppler detecting underwater acoustic signal
One of important means of lower acoustical signal.
But currently detect in the detection being only limitted to frequency stabilization signal using the underwater signal of laser interference method, actual
In application, the audible frequency of underwater signal is often time-varying, and conventional signal demodulating method is frequency spectrum analysis method, the party
Method not can determine that the instantaneous frequency of underwater signal；Moreover, the frequency of underwater signal is calculated by frequency spectrum analysis method
When, this method depends on the setting of frequency spectrum threshold value to the detection accuracy of frequency, gross error usually.
Content of the invention
The purpose of the present invention is to propose to a kind of underwater signal instantaneous frequency demodulation method based on Wavelet Ridge, to solve pin
It is frequency spectrum analysis method to existing conventional signal demodulating method, frequency spectrum analysis method not can determine that the instantaneous of underwater signal
Frequency；Calculate underwater signal frequency when, the detection accuracy of frequency is depended on the setting of frequency spectrum threshold value, usually occurs thick
The problem of error.
The present invention be employed technical scheme comprise that by solving above-mentioned technical problem：
A kind of underwater signal instantaneous frequency demodulation method based on Wavelet Ridge of the present invention, is according to following steps
Realize：
Step one, using Michelson laser interference system detect water surface；
Step 2, collection laser interference signal, described gatherer process is：Interference signal is received by a photoelectric detector, and will
It is converted into the signal of telecommunication, after this signal of telecommunication is gathered by data collecting card, sends host computer to；
Step 3, spectrum analyses are carried out to the interference signal collecting；
Step 4, determine the observing result of wavelet transformation；
Step 5, wavelet transformation is carried out to interference signal；
Step 6, the mould extraction Wavelet Ridge according to wavelet conversion coefficient；
Step 7, filter noise spot；
Step 8, determine the Wavelet Ridge center yardstick in each moment；
Step 9, each moment underwater signal instantaneous frequency is calculated according to Wavelet Ridge center yardstick.
The invention has the beneficial effects as follows：
1st, the present invention is capable of the extraction of underwater signal instantaneous frequency, that is, be capable of the spy of frequency conversion underwater signal
Survey, solve the shortcoming that routine can not demodulate instantaneous frequency.
2nd, experiment shows, the demodulation accuracy of instantaneous frequency of the present invention is better than 100Hz.
3rd, for the extraction of the underwater signal frequency of frequency stabilization, the method that the present invention adopts is than conventional frequency spectrum analysis method
There is more preferable anti-interference, the frequency measurement to frequency stabilization underwater signal for the present invention, precision can be better than 1Hz.
Brief description
Fig. 1 is typical Michelson interference system basic light path structure chart；
Fig. 2 is in specific embodiment one, and Wavelet Ridge method determines that the general step of underwater signal instantaneous frequency is illustrated
Figure；
Fig. 3 is in experimental verification of the present invention, and the not ridge feature schematic diagram of wavelet transformation in the same time, wherein (a) are t=
t3500The ridge feature schematic diagram of the wavelet transformation in moment, (b) is t=t3600The ridge feature schematic diagram of the wavelet transformation in moment；
Fig. 4 is wavelet module value scattergram in experimental verification of the present invention；
Fig. 5 is Wavelet Ridge scattergram in experimental verification of the present invention；
Fig. 6 is in experimental verification of the present invention, and frequency changes fitting a straight line result schematic diagram；
Specific embodiment
Further describe the specific embodiment of the present invention in conjunction with Fig. 1, Fig. 2.
Specific embodiment one：A kind of underwater signal instantaneous frequency demodulation based on Wavelet Ridge described in present embodiment
Method, comprises the following steps：
Step one, using Michelson laser interference system detect water surface；
Step 2, collection laser interference signal, described gatherer process is：Interference signal is received by a photoelectric detector, and will
It is converted into the signal of telecommunication, after this signal of telecommunication is gathered by data collecting card, sends host computer to；
Step 3, spectrum analyses are carried out to the interference signal collecting, for determining the frequency distribution model of underwater signal
Enclose；
Step 4, determine the observing result of wavelet transformation；
It is possible to know the frequency range of signal spectrum after step 3, morther wavelet center frequency is combined according to this scope
Rate, sample frequency can determine that the observing result of wavelet transformation.
Step 5, wavelet transformation is carried out to interference signal；
Spectrum analyses described in step 3 are to determine range scale, are not the necessary program that signal itself is processed.
Here interference signal is exactly to refer to the signal that data collecting card collects.
Step 6, the mould extraction Wavelet Ridge according to wavelet conversion coefficient；
Step 7, filter noise spot；
Exactly filtered by the method for given threshold it is simply that having to the minima of the mould of the corresponding wavelet coefficient of Wavelet Ridge
One setting, only when the mould of the corresponding wavelet coefficient of Wavelet Ridge is more than this value, this ridge point is considered as just effective.
Step 8, determine the Wavelet Ridge center yardstick in each moment；
Step 9, each moment underwater signal instantaneous frequency is calculated according to Wavelet Ridge center yardstick.
Laser interferance method detecting underwater acoustic signal is described below：
Underwater sound source sends the surface acoustic wave that acoustical signal can cause water surface horizontal transmission, generally adopts homodyne optical interference circuit
Principle detects to water surface, and typical homodyne interferometric method light path is as shown in Figure 1.
Laser interference detecting underwater acoustic signal all to be realized by way of detecting water surface sound wave, for homodyne interferometric method
Laser beam is divided into detection light and reference light by spectroscope by detection system light path, detects light and incides water surface, by water meter
Return to meet with reference beam after the sound wave modulation of face and interfere, interference signal is received by a photoelectric detector, by photodetector
Receive interference signal, and be translated into the signal of telecommunication, this signal of telecommunication can be generalized by data collecting card and capture program machine-readable
Take, be generalized the machine-readable interference signal taking and be further processed the frequency that can demodulate underwater sound source, for example, do FFT.
According to aforementioned measuring principle, the distribution of amplitudes of reference light can be expressed from the next：
Eb(t)=Absin(ω0t+kzb+φ) (1)
In formula, ω0Reference light angular frequency,
K wave number,
The initial phase of Ф laser beam.
The distribution of amplitudes of measurement light can have following formula to state：
Em(t)=Amsin(ω0t+kzm+φ) (2)
Conjunction amplitude after two-beam converges is stated by following formula：
E (t)=Eb(t)+Em(t)=Amsin(ω0t+kzm+φ)+Absin(ω0t+kzb+φ) (3)
Therefore interference light intensity can be stated by following formula：
Light intensity is received by photodetector, and detector does not respond (being changed into direct current signal) to front 3 high frequency items, because
This, the light intensity signal that removal DC component receives can be stated by following formula：
Id=KAmAbcos[k(zm-zb)]=Adcos[k(zm-zb)] (5)
In formula, K photodetector enlargement ratio.
From above formula, the signal that photodetector receives is the modulated signal with regard to reference light and measurement light optical path difference,
The optical path difference of two bundle laser is relevant with water surface Oscillation Amplitude by the initial length of two arms, optical path difference zm-zbCan be by following formula table
Show：
In formula,For the vibration of natural water surface, Assin(2πfst+φs) draw for underwater sound source
The water meter surface vibration rising, (L1-L2) for the water surface static when two-way light initial optical path difference, be designated as Δ L.Therefore photodetector connects
The light intensity signal receiving can be stated by formula (7), carries out, to this signal, the frequency that spectrum analyses can get water surface sound wave, i.e. water
The audible frequency of lower acoustical signal.
Underwater signal laser interference detection method ultimate principle based on Wavelet Ridge is as follows：
This shortcoming of underwater signal frequency, research and utilization wavelet transformation can not be determined for frequency spectrum analysis method in real time
Method process interference signal.The natural fluctuation of supposition water surface is A without loss of generalitynsin(2πfnt+φn), then according to
The long-pending formula with differenceization of trigonometric function, and Bezier identityCan be by formula (7)
It is further broken into fnAnd fsInteger harmonics item and they and frequency item and difference frequency term sum, as shown in formula (8), in formula,
x1=2kAn, x2=2kAs.
Observe the interference signal expression formula after decomposing to understand：Because the fluctuation of natural water surface is low-frequency fluctuation, interfere letter
Number spectrum distribution occur in that a very important feature, that is, with fsCentered on a frequency band in the spectrum of comparatively dense occurs
Line, and the distribution of spectral line assumes strict symmetry.The corresponding frequency of each spectral line is fs±2nfnOr fs±(2n-1)fn, n ∈ N+.
Their amplitude should be proportional to 2A respectivelydsin(2k△L)J2n(x1)J1(x2) and 2Adcos(2k△L)J2n-1(x1)J1(x2), and
fsThe amplitude of place's spectral line is then proportional to 2Adsin(2k△L)J0(x1)J1(x2).
According to These characteristics, in this frequency band, the position of spectrum peak may have two kinds of situations, depending on Bessel function
Value J0(x1) and the sine and cosine value of initial phase difference 2k Δ L depending on, or be located at f=fsPlace, or it is symmetrically dispersed in f=fs's
The left and right sides, even if the fluctuation of natural water surface has certain randomness, when such spectrum distribution feature still runs through whole
Domain scope.Therefore, when we carry out wavelet transformation to the interference signal receiving, observe in yardstick specific, small echo ridge point
Always along fsPlace size distribution, works as fsIt is time dependent amount, then small echo ridge point is then along fsDuring corresponding yardstick
Half interval contour is being distributed.Therefore according to this conclusion, we can be by calculating the position of small echo ridge point come the wink to water surface sound wave
When frequency (instantaneous frequency of underwater signal) judged.
Specific embodiment two：Present embodiment from unlike specific embodiment one：Frequency spectrum described in step 3 divides
Analysis, refers to adopt fast fourier transform algorithm to the interference signal collecting, i.e. fft algorithm.Other steps be embodied as
Mode one is identical.
Specific embodiment three：Present embodiment from unlike specific embodiment one or two：Little described in step 5
The detailed process of wave conversion is：
Selection Morlet small echo is morther wavelet, and its mathematical expression formula is
In formula, ω0For the center angular frequency of morther wavelet, σ is Gaussian function parameter, and j is imaginary symbols, and t is the time, its phase
The Fourier transformation answered is：
ω is angular frequency, then as follows to the wavelet conversion coefficient computing formula of interference signal：
In formula,A family of functions with Morlet small echo as morther wavelet, a be scale factor, b be translation because
Son, that is,It is by the translation of wavelet mother function and the flexible family of functions obtaining, f (t) is the interference collecting
Signal, Wf(a, b) is wavelet conversion coefficient.
Other steps are identical with specific embodiment one or two.
Specific embodiment four：Unlike one of present embodiment and specific embodiment one to three：Described in step 6
Mould according to wavelet conversion coefficient extract the detailed process of Wavelet Ridge and be：
Wavelet conversion coefficient W is obtained according to wavelet conversion coefficient computing formulaf(a, b), to wavelet conversion coefficient Modulus of access,
Then calculate local model maximum value using local model maximum value-based algorithm, local model maximum value point is small echo ridge point, obtains little
Distributing position (the t of wave crest point0,a0), t here0It is exactly that small echo ridge point is located the moment, a0It is exactly the yardstick that small echo ridge point is located.
The calculating process of actual small echo ridge point distributing position is as follows：Obtain after completing wavelet transformation is a series of wavelet systems
Number, if time span is m, the scale length of calculating is n, then wavelet coefficient is exactly the matrix of m*n, and we wonder t0When
The small echo ridge point distribution carved, just t=t0The wavelet coefficient in this moment is taken out, the wavelet coefficient at this time taken out
Be exactly the sequence of (1*n), the maximum calculating this sequence which position occurs that is to say, that the sequence of calculation which
Value is maximum, and the corresponding scale-value of this maximum is exactly scale-value a of small echo ridge point distributing position0.Other steps and tool
One of body embodiment one to three is identical.
Specific embodiment five：Unlike one of present embodiment and specific embodiment one to four：Described in step 8
The detailed process of the Wavelet Ridge center yardstick in each moment of determination be：
The position of small echo ridge point or be located on the corresponding dimension line of underwater signal frequency, or symmetrical point is listed in dimension line
Up and down.Therefore, for the moment of only one of which ridge point, this ridge point place yardstick is Wavelet Ridge center yardstick；
For the moment having two ridge point, then the midpoint place yardstick of this two ridge point is Wavelet Ridge center yardstick, small echo
The corresponding frequency of chi chung heart yardstick is the instantaneous frequency in this moment.
Wavelet Ridge center yardstick is exactly the yardstick corresponding to Zhi Ge Wavelet Ridge dot center, hereafter has an explanation, different moment
There are two kinds of Wavelet Ridge states, one kind is only one of which ridge point, one kind is two ridge point, during for only one of which ridge point, little
Wave crest center yardstick is exactly the corresponding yardstick of this ridge point, and during for two ridge point, Wavelet Ridge center yardstick is exactly this two
Yardstick corresponding to the midpoint of small echo ridge point.One of other steps and specific embodiment one to four are identical.
Specific embodiment six：Unlike one of present embodiment and specific embodiment one to five：Described in step 9
According to the detailed process that Wavelet Ridge center yardstick calculates each moment underwater signal instantaneous frequency be：
It is assumed that the Wavelet Ridge center yardstick of t interference signal is ac, then instantaneous frequency f of underwater signal t
Shown in computing formula such as formula (13), f in formulasSample rate for interference signal acquisition module
F=fa·fs/ac(13)
Wherein, faIt is the mid frequency of Morlet small echo, be a setting value.Other steps and specific embodiment one to
One of five is identical.
The experimental verification of the present invention is as follows：
For observe small echo ridge point characteristic distributions, using aforementioned homodyne interferometric method measuring system to frequency the water meter for 2kHz
Face sound wave carries out laser interference detection, has obtained the interference signal modulated by water surface sound wave.Well gathered with having in time-frequency domain
The parsing small echo of Jiao's property carries out wavelet transformation as wavelet basiss to this interference signal, obtains matrix of wavelet coefficients, according to set
The time interval of wavelet center frequency and signal sampling calculates underwater signal frequency 2kHz corresponding yardstick as=10.40.
Fig. 3 show two not wavelet module value in the same time with the distribution situation of dimensional variation, as seen from the figure, water surface sound wave swashs
There are two kinds of distinct ridge features in the wavelet transformation of interference of light detectable signal：Small echo ridge point or be located at underwater signal frequency
On corresponding yardstick, or divide the both sides being listed in this yardstick, consistent with theory analysis above.
Extract the accuracy of underwater signal instantaneous frequency for checking Wavelet Ridge method, to the linear change of frequency under water
Acoustical signal is detected, and sets the frequency change rate of underwater signal as 8kHz/s, this water surface sound wave is carried out with laser and does
Relate to detection, obtain interference signal and carry out the distribution of coefficient modulus value after wavelet transformation as shown in figure 4, wavelet module value as seen from the figure
The change over time of local maximum place yardstick and change, namely the distributing position of Wavelet Ridge is with water surface sound wave frequency
The change of rate and change.Small echo ridge point is distributed as shown in figure 5, the center of small echo ridge point is gradually lowered to chi by yardstick for 7
Spend for 5, this shows that Wavelet Ridge is capable of the change of real-time tracking water surface frequency of sound wave, and Wavelet Ridge place yardstick can reflect under water
The instantaneous frequency of acoustical signal.
According to the determination method of instantaneous frequency, calculate the instantaneous frequency in each moment observation time Nei, then matching frequency
Rate time straight line, calculates whether frequency change rate is matched with actual value.Fitting result is as shown in fig. 6, in figure straight line is
Frequency time change curve, the frequency change rate calculating (i.e. slope) is 8.12kHz/s, substantially matches with theoretical value,
Its error is because the factors such as noise spot when frequency resolution and Wavelet Ridge extract cause, and this demonstrate that Wavelet Ridge method carries
Take the accuracy of underwater signal instantaneous frequency.
Technical scheme main line is：1) wavelet conversion coefficient is obtained to signal wavelet transformation；2) according to localized mode
Maximum method obtains the distributing position of each moment small echo ridge point；3) when each being calculated according to the distributing position of small echo ridge point
The Wavelet Ridge center yardstick carved；4) instantaneous frequency according to wavelet center yardstick each moment of reverse.The present invention is applied under water
The detection of audible target audible frequency, liquid surface frequency of sound wave detect, the measurement of small amplitude mechanical oscillation frequencies.
Claims (5)
1. a kind of underwater signal instantaneous frequency demodulation method based on Wavelet Ridge is it is characterised in that methods described includes following step
Suddenly：
Step one, using Michelson laser interference system detect water surface；
Step 2, collection laser interference signal, described gatherer process is：Interference signal is received by a photoelectric detector, and by its turn
Turn to the signal of telecommunication, after this signal of telecommunication is gathered by data collecting card, send host computer to；
Step 3, spectrum analyses are carried out to the interference signal collecting；
Step 4, determine the observing result of wavelet transformation；
Step 5, wavelet transformation is carried out to interference signal；
Step 6, the mould extraction Wavelet Ridge according to wavelet conversion coefficient；
Step 7, filter noise spot；
Step 8, determine the Wavelet Ridge center yardstick in each moment, detailed process is：
For the moment of only one of which ridge point, this ridge point place yardstick is Wavelet Ridge center yardstick；
For the moment having two ridge point, then the midpoint place yardstick of this two ridge point is Wavelet Ridge center yardstick, in Wavelet Ridge
The corresponding frequency of heart yardstick is the instantaneous frequency in this moment；
Step 9, each moment underwater signal instantaneous frequency is calculated according to Wavelet Ridge center yardstick.
2. the underwater signal instantaneous frequency demodulation method based on Wavelet Ridge according to claim 1 is it is characterised in that walk
Spectrum analyses described in rapid three, refer to adopt fast fourier transform algorithm to the interference signal collecting, i.e. fft algorithm.
3. the underwater signal instantaneous frequency demodulation method based on Wavelet Ridge according to claim 2 is it is characterised in that walk
The detailed process of the wavelet transformation described in rapid five is：
Selection Morlet small echo is morther wavelet, and its mathematical expression formula is
In formula, ω0For the center angular frequency of morther wavelet, σ is Gaussian function parameter, and j is imaginary symbols, and t is the time, then to interference
The wavelet conversion coefficient computing formula of signal is as follows：
In formula,It is a family of functions with Morlet small echo as morther wavelet, a is scale factor, b is shift factor, that is,It is by the translation of wavelet mother function and the flexible family of functions obtaining, f (t) is the interference signal collecting,
Wf(a, b) is wavelet conversion coefficient.
4. the underwater signal instantaneous frequency demodulation method based on Wavelet Ridge according to claim 3 is it is characterised in that walk
The detailed process that mould according to wavelet conversion coefficient described in rapid six extracts Wavelet Ridge is：
Wavelet conversion coefficient W is obtained according to wavelet conversion coefficient computing formulaf(a, b), to wavelet conversion coefficient Modulus of access, then
Calculate the distributing position (t that local model maximum is worth to small echo ridge point using local model maximum value-based algorithm0,a0), t here0Just
It is that small echo ridge point is located the moment, a0It is exactly the yardstick that small echo ridge point is located.
5. the underwater signal instantaneous frequency demodulation method based on Wavelet Ridge according to claim 4 is it is characterised in that walk
Described in rapid nine according to the detailed process that Wavelet Ridge center yardstick calculates each moment underwater signal instantaneous frequency it is：
It is assumed that the Wavelet Ridge center yardstick of t interference signal is ac, then instantaneous frequency f of underwater signal t calculates public
Shown in formula such as formula (13), f in formulasSample rate for interference signal acquisition module
F=fa·fs/ac(13)
Wherein, faIt is the mid frequency of Morlet small echo, be a setting value.
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| CN105487077B (en) * | 2015-12-29 | 2017-11-03 | 哈尔滨工业大学 | The location estimation method of audible target under water based on laser multiple spot coherent detection and the device for realizing this method |
| CN105606194B (en) * | 2015-12-29 | 2018-09-07 | 哈尔滨工业大学 | A kind of underwater signal real time extracting method based on laser orthogonal polarization interferometry technology |
| CN106595836B (en) * | 2016-12-26 | 2019-04-26 | 哈尔滨工业大学 | Frequency extraction method in the case of underwater double sound source spectral aliasing |
| CN107966205A (en) * | 2017-10-20 | 2018-04-27 | 哈尔滨工业大学（威海） | A kind of underwater target acoustic detection method and device based on coherent laser |
| CN108875124B (en) * | 2018-04-26 | 2022-04-01 | 哈尔滨工业大学 | Maximum value compensation algorithm for extracting peak value position of confocal axial response curve |
| CN114659610B (en) * | 2022-03-09 | 2024-02-23 | 中国科学院国家天文台南京天文光学技术研究所 | Homodyne laser interference vibration measurement system based on pupil plane imaging and wavelet transformation |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102721824A (en) * | 2012-06-27 | 2012-10-10 | 中国科学院力学研究所 | Method and device for measuring particle velocity with low velocity and high acceleration characteristics |
| CN102735759A (en) * | 2012-07-13 | 2012-10-17 | 南京信息工程大学 | Lamb wave signal de-noising method based on ridge |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8827917B2 (en) * | 2008-06-30 | 2014-09-09 | Nelleor Puritan Bennett Ireland | Systems and methods for artifact detection in signals |
-
2014
- 2014-11-20 CN CN201410668406.7A patent/CN104316160B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102721824A (en) * | 2012-06-27 | 2012-10-10 | 中国科学院力学研究所 | Method and device for measuring particle velocity with low velocity and high acceleration characteristics |
| CN102735759A (en) * | 2012-07-13 | 2012-10-17 | 南京信息工程大学 | Lamb wave signal de-noising method based on ridge |
Non-Patent Citations (3)
| Title |
|---|
| 基于Morlet小波的水下声信号频率识别;张晓琳等;《光电子·激光》;20101231;第21卷(第12期);第1839-1841页 * |
| 基于动态规划提取信号小波脊和瞬时频率;王超等;《中南大学学报(自然科学版)》;20081231;第39卷(第6期);第1331-1336页 * |
| 水声信号参数估计与分析;许光;《中国优秀硕士学位论文全文数据库信息科技辑》;20140615(第6期);第49-59页 * |
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