本技术介绍了一种在非高斯噪声条件下利用深度学习进行脉冲信号重建的方法。该技术旨在克服传统方法中对海洋环境噪声高斯分布的假设限制,通过深度学习模型有效处理非高斯统计特性的噪声,实现更准确的脉冲信号重建。
背景技术
海洋环境中包含多种干扰源,如鱼虾等海洋生物发声、船舶航行和海底钻探等,这些高能量干扰源产生的干扰信号往往具有非高斯统计特性[1-4]([1]Y.Li,X.Ma,L.Wang,and Y.Liu,“Using deep learning to de-noise and reconstruct pulse signals innon-Gaussian environment,”Journal of Applied Acoustics,vol.40,no.1,pp.131-141,Jan.,2021,doi:10.11684/j.issn.1000-310X.2021.01.016.[2]X.Mo,H.Wen,andY.Yang,“A parameter estimation method ofαstabledistribution and itsapplication in the statistical modeling of ice-generated noise,”ActaAcustica,vol.48,no.2,pp.319-326,Mar.,2023,doi:10.15949/j.cnki.0371-0025.2023.02.001.[3]G.Song,X.Guo,and L.Ma,“αstabledistribution model in oceanambient noise,”Acta Acustica,vol.44,no.2,pp.177-188,Mar.,2019,doi:10.15949/j.cnki.0371-0025.2019.02.004.[4]F.Traverso,G.Vernazza,and A.Trucco,“Simulation ofnon-White and non-Gaussian underwater ambient noise,”Oceans-Yeosu,2012,pp.1-10.)并导致接收信号信干噪比显著降低。由于非高斯干扰的统计特性显著偏离了正态分布,并伴随着非平稳性的特征,这使得其二阶矩发散,从而导致基于高斯分布假设的传统方法[5-6]([5]Z.Zhao,Q.Li,Z.Xia,and D.Shang,“A Single-HydrophoneCoherent-Processing Method for Line-Spectrum Enhancement,”Remote Sens.,vol.15,no.3,pp.659,Jan.,2023,doi:10.3390/rs15030659.[6]C.Xing,Y.Wu,L.Xie,andD.Zhang,“Asparse dictionary learning-based denoising method for underwateracoustic sensors,”Appl.Acoust.,vol.180,pp.108140.1–108140.13,Apr.,2021,doi:10.1016/j.apacoust.2021.108140.)在面对非高斯干扰时,其权值迭代过程可能不收敛,无法有效实现干扰抑制与信号重构,传统方法的信号处理性能显著降低[7-9]([7]H.Yang,Y.Cheng,and G.Li,“A denoising method for ship radiated noise based onSpearman variational mode decomposition,spatial-dependence recurrence sampleentropy,improved wavelet threshold denoising,and Savitzky-Golay filter,”Alex.Eng.J.,vol.60,no.3,pp.3379-3400,Jan.,2021,doi:10.1016/j.aej.2021.01.055.[8]J.Wang,J.Li,S.Yan,W.Shi,X.Yang,Y.Guo,and T.Gulliver,“Anovel underwateracoustic signal denoising algorithm for Gaussian/Non-Gaussian impulsivenoise,”IEEE Trans.Veh.Technol.,vol.70,no.1,pp.429-445,Jan.,2021,doi:10.1109/TVT.2020.3044994.[9]Y.Li,and L.Wang,“A novel noise reduction technique forunderwater acoustic signals based on complete ensemble empirical modedecomposition with adaptive noise,minimum mean square variance criterion andleast mean square adaptive filter,”Def.Technol.,vol.16,no.3,pp.543-554,Jun.,2020,doi:10.1016/j.dt.2019.07.020.)。再加上非高斯干扰在时间波形上具有较为显著的尖峰脉冲特性,与目标脉冲信号特性较为相似,使得脉冲信号重构更加困难。如何充分利用水声脉冲信号的特性,解决低输入信干噪比与非高斯干扰背景下的脉冲信号重构问题有待解决。
深度神经网络具有卓越的特征自动提取与学习能力,能够深入挖掘并理解复杂信号中的潜在结构和特征,通过多层非线性变换,捕捉到传统方法难以捕捉的精细信息。近年来,基于深度神经网络的信号降噪与重构方法[10-15]([10]X.Wang,Y.Zhao,X.Teng,andW.Sun,“A stacked convolutional sparse denoising autoencoder model forunderwater heterogeneous information data,”Appl.Acoust.,vol.167,Oct.,2020,Art.no.107391,doi:10.1016/j.apacoust.2020.107391.[11]Y.Song,F.Liu,and T.Shen,“A novel noise reduction technique for underwater acoustic signals based ondual-path recurrent neural network,”IET Commun.,vol.17,no.2,pp.135-144,Oct.,2022,doi:10.1049/cmu2.12518.[12]X.Zhou,and K.Yang,“Adenoising representationframework for underwater acoustic signal recognition,”J.Acoust.Soc.Am.,vol.147,no.4,pp.EL377-EL383,Apr.,2020,doi:10.1121/10.0001130.[13]D.Ju,C.Chi,Z.Li,Y.Li,C.Zhang,and H.Huang,“Deep-learning-based line enhancer for passivesonar systems,”IET Radar Sonar Nav.,vol.16,no.3,pp.589-601,Dec.,2021,doi:10.1049/rsn2.12205.[14]J.Yin,W.Luo,L.Li,X.Han,L.Guo,and J.Wang,“Enhancementof underwater acoustic signal based on denoising automatic-encoder,”Journalon Communications,vol.40,no.10,pp.119-126,Oct.,2019,doi:10.11959/j.issn.1000-436x.2019181.[15]R.Zaheer,I.Ahmad,Q.Viet Phung,and D.Habibi,“Blind SourceSeparation and Denoising of Underwater Acoustic Signals,”IEEE Access,vol.12,pp.80208-80222,Jun.,2024,doi:10.1109/ACCESS.2024.3410276.)正在快速发展。基于深度学习的降噪技术主要划分为两大类:直接映射及掩膜分离方法。直接映射方法以纯净信号为学习目标,通过端到端的神经网络模型直接从带噪信号中恢复出纯净信号。如文献[16]([16]A.A.Nair,and K.Koishida,“Cascaded time+time-frequency Unet forspeech enhancement:jointly addressing clipping,codec distortions,and gaps,”inICASSP,2021,pp.7153-7157.)将UNet网络[17]([17]O.Ronneberger,P.Fischer,andT.Brox,“U-Net:convolutional networks for biomedical image segmentation,”inMICCAI,2015,pp.234-241.)应用于信号的降噪上,通过跳接的U型网络结构有效融合了浅层与深层特征,显著提升了信号的降噪效果。进一步地,CBDNet网络[18]([18]S.Guo,Z.Yan,K.Zhang,W.Zuo,and M.Wang,“Toward convolutional blind denoising of realphotographs,”in CVPR,2019,pp.1712-1722.)将全卷积网络与UNet网络相结合,前者负责估计输入数据中的噪声成分,后者则利用全卷积网络得到的噪声估计值进行降噪。RIDNet网络[19]([19]S.Anwar,and N.Barnes,“Real image denoising with featureattention,”in ICCV,2019,pp.3155-3164.)通过引入残差结构进行特征提取并结合注意力机制实现输入数据的降噪,展现了注意力机制在信号处理中的潜力。掩膜分离方法侧重于估算带噪信号与纯净信号之间的掩膜,利用掩膜实现输入信号的降噪,恢复出更为清晰的声学信号。如文献[20]([20]Y.Song,F.Liu,and T.Shen,“Method of UnderwaterAcoustic Signal Denoising Based on Dual-Path Transformer Network,”IEEEAccess,vol.12,pp.81483-81494,Nov.,2024,doi:10.1109/ACCESS.2022.3224752.)采用双路径Transformer网络构建掩膜,并利用Transformer网络的序列建模能力捕捉长期依赖,成功实现了时域上的水声信号降噪。为了进一步提升模型的降噪性能,文献[21]([21]J.Fan,J.Yang,X.Zhang,and C.Zheng,“Monaural speech enhancement using U-netfused with multi-head self-attention,”Acta Acustica,vol.47,no.6,pp.703-716,Nov.,2022,doi:10.15949/j.cnki.0371-0025.2022.06.007.)提出了TUNet模型,该模型融合了UNet网络的多尺度特征融合能力与多头注意力机制的双路径Transformer结构,利用Transformer结构构建掩膜分离结构实现了基于时域的单通道信号降噪。
实现思路