CN105429720B - The Time Delay Estimation Based reconstructed based on EMD - Google Patents

The Time Delay Estimation Based reconstructed based on EMD Download PDF

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CN105429720B
CN105429720B CN201510833172.1A CN201510833172A CN105429720B CN 105429720 B CN105429720 B CN 105429720B CN 201510833172 A CN201510833172 A CN 201510833172A CN 105429720 B CN105429720 B CN 105429720B
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time delay
sequence
emd
echo signal
signal
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CN105429720A (en
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孙山林
周卓伟
李云
陈庞森
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Guilin University of Aerospace Technology
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    • GPHYSICS
    • G10MUSICAL INSTRUMENTS; ACOUSTICS
    • G10LSPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING
    • G10L25/00Speech or voice analysis techniques not restricted to a single one of groups G10L15/00 - G10L21/00
    • G10L25/03Speech or voice analysis techniques not restricted to a single one of groups G10L15/00 - G10L21/00 characterised by the type of extracted parameters
    • G10L25/24Speech or voice analysis techniques not restricted to a single one of groups G10L15/00 - G10L21/00 characterised by the type of extracted parameters the extracted parameters being the cepstrum
    • GPHYSICS
    • G10MUSICAL INSTRUMENTS; ACOUSTICS
    • G10LSPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING
    • G10L25/00Speech or voice analysis techniques not restricted to a single one of groups G10L15/00 - G10L21/00
    • G10L25/03Speech or voice analysis techniques not restricted to a single one of groups G10L15/00 - G10L21/00 characterised by the type of extracted parameters
    • G10L25/18Speech or voice analysis techniques not restricted to a single one of groups G10L15/00 - G10L21/00 characterised by the type of extracted parameters the extracted parameters being spectral information of each sub-band
    • GPHYSICS
    • G10MUSICAL INSTRUMENTS; ACOUSTICS
    • G10LSPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING
    • G10L25/00Speech or voice analysis techniques not restricted to a single one of groups G10L15/00 - G10L21/00
    • G10L25/03Speech or voice analysis techniques not restricted to a single one of groups G10L15/00 - G10L21/00 characterised by the type of extracted parameters
    • G10L25/21Speech or voice analysis techniques not restricted to a single one of groups G10L15/00 - G10L21/00 characterised by the type of extracted parameters the extracted parameters being power information

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Computational Linguistics (AREA)
  • Signal Processing (AREA)
  • Health & Medical Sciences (AREA)
  • Audiology, Speech & Language Pathology (AREA)
  • Human Computer Interaction (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
  • Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)

Abstract

The invention discloses a kind of Time Delay Estimation Based reconstructed based on EMD, it is characterized in that, comprise the following steps:1) sample sequence y is obtained1(n)、y2(n) leading ambient noise sequence b, is extracted1(n)、b2(n);2) sample sequence y is obtained1(n) cepstrum sequenceObtain leading ambient noise sequence b1(n) cepstrum sequence3) obtainSound channel responseWithSound channel responseObtainSpectral enveloping lineWithSpectral enveloping lineObtain spectral difference curve D1(ω), obtains normalizing spectral difference curve4) obtainAmplitude is higher than thresholding T1 ghz area;5) m Intrinsic mode functions are obtained;6) the Power Spectrum Distribution curve per group component, ratio calculated η are obtained1, obtain the reconstruction signal of echo signal;7) to the reconstruction signal C of echo signal1(n)、C2(n) secondary correlated seriesPeak value carries out detection and can obtain time delay estimateThis method improves the Stability and veracity of time delay estimated result in the case of low signal-to-noise ratio.

Description

The Time Delay Estimation Based reconstructed based on EMD
Technical field
It is specific a kind of based on EMD (Empirical Mode the present invention relates to array signal process technique Decomposition, empirical mode decomposition, abbreviation EMD) reconstruct Time Delay Estimation Based.
Background technology
As the key technology of auditory localization, the estimation of sodar time delay is always that the focus of array signal processing area research is asked Topic, and it has been applied to a variety of occasions such as underwater target tracking and positioning, Satellite tool kit, intelligent robot.
Traditional delay time estimation method has:General cross correlation, the adaptive side filtering estimation technique, mean square deviation function method Deng.
General cross correlation, refers to document:“C.H.Knapp and C.G.Carter.The generalized correlation method for estimation of time delay[J].IEEE Trans,Acoustics, Speech and Signal Processing, 1976,21 (2), pp.320-327. " can accurately estimate in high s/n ratio Time delay, but the weighting function needed for it can not be predefined in the application of physical presence reverberation noise, can only with estimate come Instead of so that measurement accuracy is poor and unstable under the actual low signal-to-noise ratio of general cross correlation.
Adaptively side filters the estimation technique, refers to document:“F.A.Reed,P.L.Feintuch and N.J.Bershad.Time delay estimation using the LMS adaptive filter–behavior[J] .IEEE Transactions on Acoustics,Speech and Signal Processing.1981,29(3), Pp.561-571. ", by setting iterative initial value, parameter and adaptive learning come estimation time delay, but this method needs to assume logical Ambient noise between road is incoherent white Gaussian noise, estimates that accuracy rate declines under actual noise environment.
Mean square deviation function method, refers to document:“G.Jacovitti and G.Scarano.Discrete Time Techniques for Time Delay Estimation[J].IEEE Transactions on Signal Processing, 1993,41 (2), pp.525-533. " can reach best estimate in no influence of noise, but ought exist Estimate that accuracy is substantially reduced during actual noise, it is its greatest problem to resist changeable noise jamming ability.
For the situation of low signal-to-noise ratio, above method is in practical application at this stage, and effect is less desirable, actual to answer In the urgent need to a kind of delay time estimation method that noiseproof feature is good, sane in.
The content of the invention
The purpose of the present invention be in view of the shortcomings of the prior art, and provide it is a kind of based on EMD reconstruct associated time delays estimation Method.This method can improve the Stability and veracity of time delay estimated result in the case of low signal-to-noise ratio.
Realizing the technical scheme of the object of the invention is:
The Time Delay Estimation Based reconstructed based on EMD, is comprised the following steps:
1) two-way echo signal is gathered, the sample sequence y of two-way echo signal is obtained1(n)、y2(n), and two-way mesh is extracted Mark the leading ambient noise sequence b of signaling channel1(n)、b2(n), because two-way echo signal exists when reaching two reception sensors Time delay σ, therefore sample sequence y1And y (n)2(n) there is also time delay σ between;
2) to sample sequence y1(n) carry out discrete Fourier transform and obtain Y1(ω), by Y1The amplitude of (ω), which is taken the logarithm, to be obtainedIt is right againCarry out inverse Fourier transform and obtain sample sequence y1(n) cepstrum sequenceObtained by same mode To echo signal channel leading ambient noise sequence b1(n) cepstrum sequence
3) willIt is filtered, respectively obtainsSound channel responseWithSound channel responseIt is rightFourier transformation is carried out respectively to obtainSpectral enveloping lineFrequency spectrum EnvelopeIt is rightDo the difference of two squares and eliminate reciprocity noise, and divided by instantaneous background noise energy Obtain spectral difference curve D1(ω), then to spectral difference curve D1(ω), which is normalized, to be obtained normalizing spectral difference curve
4) obtained with threshold methodAmplitude is higher than thresholding T1 ghz area, it is assumed that meeting the ghz area of condition has k Individual, k numerical value is relevant with the distribution of signal spectrum energy, and the numerical value obtained under the conditions of varying environment is different, correspondence echo signal In contained voice signal composition dominate frequency range and be designated as:[ωp11q11]、......、[ωp1kq1k];
5) to sample sequence y1(n) EMD decomposition is carried out, m Intrinsic mode functions are obtained successively, are designated as:h11(n), h12 (n) ... ..., h1m(n), and one decompose after surplus r1(n), such y1(n) Intrinsic mode functions can be just expressed as and remaining The sum of item, i.e.,It is adaptive, therefore m numerical value and sample sequence that EMD, which decomposes obtained component, y1(n) the spectrum distribution situation of itself is relevant, sample sequence y1(n) frequency content is abundanter, and m numerical value is bigger;
6) calculated by Fourier transformation and obtain every group component h11(n)......h1m(n) Power Spectrum Distribution curve H11 (ω)......H1m(ω);The Power Spectrum Distribution curve per group component is calculated in frequency range [ωp11q11]、......、[ωp1k, ωq1k] in the cumulative ratio η cumulative with global amplitude of amplitude1If respective components calculate obtained η1More than predetermined threshold value TH, then the component be used as the composition of echo signal all the way reconstruction signal C1(n) one of component, otherwise abandons the component;
7) by another road sample sequence y2(n) according to step 2)-step 6) same operation is carried out, obtain another road target Signal reconstruction signal C2(n), it is assumed that the signal after the reconstruct of two-way echo signal is expressed as C1And C (n)2(n), by C1(n) and C2(n) carry out secondary correlation and obtain C1(n)、C2(n) secondary correlated seriesTo secondary correlated seriesPeak value carry out detection can obtain time delay estimate(refer to document:" Tang Beautiful, row letter man of virtue and ability is based on secondary related delay time estimation method [J] computer engineering, 33 (21), pp.266- in 2007 267.”)。
The sample sequence y1(n)、y2(n) be two sensor synchronous acquisitions time sampling sequence, sample frequency is Fs =8000Hz;
Described thresholding T1 is 0.7-0.9, and preferred value is 0.8.
Described predetermined threshold value TH is 0.5.
Described spectral difference curve D1(ω) is:
Described normalization spectral difference curveFor:
Described ratio η1For:Wherein H (ω) represents any The Fourier transformation of Intrinsic mode functions function.
This method is directed to the time delay estimation in the case of low signal-to-noise ratio, and secondary associated time delays are estimated and empirical mode decomposition Algorithm is combined, and is separated by cepstrum, Fourier transformation and frequency spectrum make poor method, realize useful signal dominant component after EMD is decomposed Selection.This method improves the Stability and veracity of time delay estimated result in the case of low signal-to-noise ratio.
Brief description of the drawings
Fig. 1 is embodiment method flow schematic diagram.
Embodiment
Present disclosure is further elaborated with reference to the accompanying drawings and examples, but is not the limit to the present invention It is fixed.
Embodiment:
Reference picture 1, the Time Delay Estimation Based reconstructed based on EMD, is comprised the following steps:
1) two-way echo signal is gathered, the sample sequence y of two-way echo signal is obtained1(n)、y2(n), and two-way mesh is extracted Mark the leading ambient noise sequence b of signaling channel1(n)、b2(n), because two-way echo signal exists when reaching two reception sensors Time delay σ, therefore sample sequence y1And y (n)2(n) there is also time delay σ between;
2) to sample sequence y1(n) carry out discrete Fourier transform and obtain Y1(ω), by Y1The amplitude of (ω), which is taken the logarithm, to be obtainedIt is right againCarry out inverse Fourier transform and obtain sample sequence y1(n) cepstrum sequencePass through same mode Obtain echo signal channel leading ambient noise sequence b1(n) cepstrum sequence
3) willIt is filtered, respectively obtainsSound channel responseWithSound channel responseIt is rightFourier transformation is carried out respectively to obtainSpectral enveloping lineFrequency spectrum EnvelopeIt is rightDo the difference of two squares and eliminate reciprocity noise, and divided by instantaneous background noise energy Obtain spectral difference curve D1(ω), then to spectral difference curve D1(ω), which is normalized, to be obtained normalizing spectral difference curve
4) obtained with threshold methodAmplitude is higher than thresholding T1 ghz area, it is assumed that meeting the ghz area of condition has k Individual, k numerical value is relevant with the distribution of signal spectrum energy, and the numerical value obtained under the conditions of varying environment is different, correspondence echo signal In contained voice signal composition dominate frequency range and be designated as:[ωp11q11]、......、[ωp1kq1k];
5) to sample sequence y1(n) EMD decomposition is carried out, m Intrinsic mode functions are obtained successively, are designated as:h11(n), h12 (n) ... ..., h1m(n), and one decompose after surplus r1(n), such y1(n) Intrinsic mode functions can be just expressed as and remaining The sum of item, i.e.,It is adaptive, therefore m numerical value and sample sequence that EMD, which decomposes obtained component, y1(n) the spectrum distribution situation of itself is relevant, sample sequence y1(n) frequency content is abundanter, and m numerical value is bigger;
6) calculated by Fourier transformation and obtain every group component h11(n)......h1m(n) Power Spectrum Distribution curve H11 (ω)......H1m(ω);The Power Spectrum Distribution curve per group component is calculated in frequency range [ωp11q11]、......、[ωp1k, ωq1k] in the cumulative ratio η cumulative with global amplitude of amplitude1If respective components calculate obtained η1More than predetermined threshold value TH, then the component be used as the composition of echo signal all the way reconstruction signal C1(n) one of component, otherwise abandons the component;
7) by another road sample sequence y2(n) according to step 2)-step 6) same operation is carried out, obtain another road target Signal reconstruction signal C2(n), it is assumed that the signal after the reconstruct of two-way echo signal is expressed as C1And C (n)2(n), by C1(n) and C2(n) carry out secondary correlation and obtain C1(n)、C2(n) secondary correlated seriesTo secondary correlated seriesPeak value carry out detection can obtain time delay estimate
The sample sequence y1(n)、y2(n) be two sensor synchronous acquisitions time sampling sequence, sample frequency is Fs =8000Hz;
Described thresholding T1 values are 0.8.
Described predetermined threshold value TH is 0.5.
Step 3) middle acquisitionWithSound channel response includes below scheme:
Rectangular window function window (n), window width n are set on inverted frequency axle0, window function is expressed as:
The width of window function is relevant with the length of sample frequency and Fourier transformation, in order thatWithThrough in Fu Envelope after leaf transformation is real function, and window function needs to meet symmetry;
WillIt is multiplied with window function, obtains sound channel response
Described spectral difference curve D1(ω) is:
Described normalization spectral difference curveFor:
Described ratio η1For:Wherein H (ω) represents any The Fourier transformation of Intrinsic mode functions function.

Claims (6)

1. the Time Delay Estimation Based reconstructed based on EMD, it is characterized in that, comprise the following steps:
1) two-way echo signal is gathered, the sample sequence y of two-way echo signal is obtained1(n)、y2(n), and extract two-way target letter The leading ambient noise sequence b of number channel1(n)、b2(n), because two-way echo signal has time delay when reaching two reception sensors σ, therefore sample sequence y1And y (n)2(n) there is also time delay σ between;
2) to sample sequence y1(n) carry out discrete Fourier transform and obtain Y1(ω), by Y1The amplitude of (ω), which is taken the logarithm, to be obtainedIt is right againCarry out inverse Fourier transform and obtain sample sequence y1(n) cepstrum sequenceObtained by same mode To echo signal channel leading ambient noise sequence b1(n) cepstrum sequence
3) willIt is filtered, respectively obtainsSound channel responseWithSound channel response It is rightFourier transformation is carried out respectively to obtainSpectral enveloping lineSpectral enveloping lineIt is rightDo the difference of two squares and eliminate reciprocity noise, and divided by instantaneous background noise energyComposed Poor curve D1(ω), then to spectral difference curve D1(ω), which is normalized, to be obtained normalizing spectral difference curve
4) obtained with threshold methodAmplitude is higher than thresholding T1 ghz area, it is assumed that meeting the ghz area of condition has k individual, right The contained leading frequency range of voice signal composition in echo signal is answered to be designated as:[ωp11q11]、......、[ωp1kq1k];
5) to sample sequence y1(n) EMD decomposition is carried out, m Intrinsic mode functions are obtained successively, are designated as:h11(n), h12 (n) ... ..., h1m(n), and one decompose after surplus r1(n), such y1(n) Intrinsic mode functions can be just expressed as and remaining The sum of item, i.e.,
6) calculated by Fourier transformation and obtain every group component h11(n)......h1m(n) Power Spectrum Distribution curve H11 (ω)......H1m(ω);The Power Spectrum Distribution curve per group component is calculated in frequency range [ωp11q11]、......、[ωp1k, ωq1k] in the cumulative ratio η cumulative with global amplitude of amplitude1If respective components calculate obtained η1More than predetermined threshold value TH, then the component be used as the composition of echo signal all the way reconstruction signal C1(n) one of component, otherwise abandons the component;
7) by another road sample sequence y2(n) according to step 2)-step 6) same operation is carried out, obtain another road echo signal Reconstruction signal C2(n), the signal after the reconstruct of two-way echo signal is expressed as C1And C (n)2(n), by C1And C (n)2(n) carry out Secondary correlation obtains C1(n)、C2(n) secondary correlated seriesTo secondary correlated seriesPeak value enter Row detection can obtain time delay estimate
2. the Time Delay Estimation Based according to claim 1 reconstructed based on EMD, it is characterized in that, the sample sequence y1 (n)、y2(n) be two sensor synchronous acquisitions time sampling sequence, sample frequency is Fs=8000Hz.
3. the Time Delay Estimation Based according to claim 1 reconstructed based on EMD, it is characterized in that, described thresholding T1 For 0.7-0.9.
4. the Time Delay Estimation Based according to claim 1 reconstructed based on EMD, it is characterized in that, described thresholding T1 For 0.8.
5. the Time Delay Estimation Based according to claim 1 reconstructed based on EMD, it is characterized in that:Described pre- gating Limit value TH is 0.5.
6. the Time Delay Estimation Based according to claim 1 reconstructed based on EMD, it is characterized in that:Described spectral difference is bent Line D1(ω) is:
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CN109116301B (en) * 2018-08-14 2023-02-28 中国电子科技集团公司第三十八研究所 Time difference of arrival measuring method based on confidence degree estimation
CN109884893B (en) * 2019-02-28 2021-09-10 西安理工大学 Multi-process variable dynamic time lag estimation method
CN110514294A (en) * 2019-08-30 2019-11-29 鞍钢矿业爆破有限公司 A kind of blasting vibration signal noise-reduction method based on EMD and VMD
CN113395124B (en) * 2021-08-17 2021-11-02 清华大学 Time delay estimation method and device based on time shift variance

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