改进EMD与小波阈值相结合的光生混沌信号降噪
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摘要
超宽谱混沌信号经过经验模态分解(EMD)后得到具有不同时间特征尺度的固有模态函数(IMF)分量,由于各分量中噪声与信号同时存在,会发生模态混叠。针对此问题,提出一种改进EMD与小波阈值法相结合的光生混沌信号降噪方法。首先对经过EMD分解后的IMF分量采用两种不同阈值函数分别对信号主导模态分量和噪声主导模态分量进行去噪处理,然后将提取出的信号成分相加重构得到混沌信号。仿真结果表明:该方法能够有效地去除噪声,且降噪效果优于已有的EMD分解去噪方法,可进一步提高重构信号的信噪比,降低其均方误差,是一种有效可行的光生混沌信号降噪方法。
The empirical mode decomposition(EMD)of the ultra-wideband chaotic signals is used to obtain the intrinsic mode function(IMF)components with different time feature scales.Because the noise and the signal exist in each component simultaniously,the modal aliasing may occur.Therefore,a photogenerated chaotic signal denoising method based on the improved EMD and wavelet threshold method is proposed in this paper.The IMF component is decomposed by EMD.Two different threshold functions are used to denoise the signal dominant modal component and noise dominant modal component respectively,and then the extracted signal components are added and reconstructed to obtain the chaos signal.The simulation results indicate that the method can remove the noise effectively,improve the signal-to-noise ratio further,reduce the mean square error,and its noise reduction effect is superior to the existing EMD denoising method,which is a feasible denoising method for the photogenerated chaotic signal.
The empirical mode decomposition(EMD)of the ultra-wideband chaotic signals is used to obtain the intrinsic mode function(IMF)components with different time feature scales.Because the noise and the signal exist in each component simultaniously,the modal aliasing may occur.Therefore,a photogenerated chaotic signal denoising method based on the improved EMD and wavelet threshold method is proposed in this paper.The IMF component is decomposed by EMD.Two different threshold functions are used to denoise the signal dominant modal component and noise dominant modal component respectively,and then the extracted signal components are added and reconstructed to obtain the chaos signal.The simulation results indicate that the method can remove the noise effectively,improve the signal-to-noise ratio further,reduce the mean square error,and its noise reduction effect is superior to the existing EMD denoising method,which is a feasible denoising method for the photogenerated chaotic signal.
引文
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[15]宁静,诸昌钤,高品贤,等.EMD分解中端点数据的延长方法问题研究[J].计算机工程与应用,2011,47(3):125-128.NING J,ZHU C Q,GAO P X,et al.Study on extension method of endpoint data in EMD decomposition[J].Computer engineering and applications,2011,47(3):125-128.
[16]杨航,郭晓金.一种改善EMD端点问题的方法[J].计算机工程与应用,2016,52(8):266-270.YANG H,GUO X J.A method to improve EMD endpoint problem[J].Computer engineering and applications,2016,52(8):266-270.
[17]许宝杰,张建民,徐小力,等.抑制EMD端点效应方法的研究[J].北京理工大学学报,2006,26(3):196-200.XU B J,ZHANG J M,XU X L,et al.Research on methods of suppressing EMD endpoint effect[J].Journal of Beijing Institute of Technology,2006,26(3):196-200.
[18]张洋,王健琪,荆西京,等.HHT在生物雷达回波信号噪声抑制中的应用[J].医疗卫生装备,2012,33(5):14-17.ZHANG Y,WANG J Q,JING X J,et al.Application of HHT in noise suppression of bio-radar echo signal[J].Medical equipment,2012,33(5):14-17.
[2]KEM A,BLANK D,STOOP R.Projective noise reduction with dynamic neighborhood selection[C]//Proceeding of 2000 IEEE International Symposium on Circuits and Systems.Geneva:IEEE,2000:129-132.
[3]刘元峰,赵玫.基于奇异谱分析的混沌序列降噪[J].上海交通大学学报,2003,37(5):778-780.LIU Y F,ZHAO M.Noise reduction of chaotic sequences based on singular spectrum analysis[J].Journal of Shanghai Jiao Tong University,2003,37(5):778-780.
[4]郭凤霞,戚俊,陈斐楠,等.基于小波变换的声雷达模拟信号去噪研究[J].现代雷达,2016,38(3):86-90.GUO F X,QI J,CHEN F N,et al.Research on de-noising of acoustic radar analogue signal based on wavelet transform[J].Modern radar,2016,38(3):86-90.
[5]位秀雷,林瑞霖,刘树勇,等.基于改进小波变换方法的混沌信号去噪研究[J].武汉理工大学学报,2013,37(5):1062-1065.WEI X L,LIN R L,LIU S Y,et al.Research on chaotic signal de-noising based on improved wavelet transform[J].Journal of Wuhan University of Technology,2013,37(5):1062-1065.
[6]WEISS L G.Wavelets and wideband correlation processing[J].IEEE signal processing magazine,1994,11(1):13-32.
[7]HUANG N E,SHEN Z,LONG S R.The empirical mode decomposition and Hilbert spectrum for nonlinear and nonstationary time series analysis[J].Mathematical,physical and engineering sciences,1998,454(1971):903-995.
[8]张樯,周西峰,王瑾,等.基于改进的EMD超声信号降噪方法研究[J].南京邮电大学学报(自然科学版),2016,36(2):49-55.ZHANG Q,ZHOU X F,WANG J,et al.Research on noise reduction method based on improved EMD ultrasonic signal[J].Journal of Nanjing University of Posts and Telecommunications(natural science),2016,36(2):49-55.
[9]WU Z,HUANG N E.Study of the characteristic of white noise using the empirical mode decomposition method[J].Mathematical,physical and engineering sciences,2004,460(2046):1597-1611.
[10]HUANG Daji,ZHAO Jinping,SU Jilan.On the end extending in the Hilbert-Huang Transform[J].Progress in coastal engineering and oceanography,1991(1):81-92.
[11]郭中华,李树庆,王磊,等.自适应阈值的小波去噪改进算法研究[J].重庆邮电大学学报(自然科学版),2015,27(6):740-744.GUO Z H,LI S Q,WANG L,et al.An improved algorithm of adaptive threshold based on wavelet de-noising[J].Journal of Chongqing University of Posts and Telecommunications(natural science),2015,27(6):740-744.
[12]刘晓艳,贾明涛.基于改进EMD-小波阈值联合去噪的城市地下管线识别与定位[J].中国安全生产科学技术,2015,11(6):56-62.LIU X Y,JIA M T.Identification and localization of urban underground pipelines based on improved EMD-wavelet threshold combined de-noising[J].Journal of safety science and technology,2015,11(6):56-62.
[13]王峰林,王长龙,朱红运.基于EMD的改进小波阈值降噪法在超声信号处理中的应用[J].军械工程学院学报,2013,25(3):35-39.WANG F L,WANG C L,ZHU H Y.Application of improved wavelet threshold noise reduction based on EMD in ultrasonic signal processing[J].Journal of Ordnance Engineering College,2013,25(3):35-39.
[14]陈益,李书.改进的小波阈值消噪法应用于超声信号处理[J].北京航空航天大学学报,2006,32(4):466-470.CHEN Y,LI S.Application of improved wavelet threshold denoising in ultrasonic signal processing[J].Journal of Beijing University of Aeronautics and Astronautics,2006,32(4):466-470.
[15]宁静,诸昌钤,高品贤,等.EMD分解中端点数据的延长方法问题研究[J].计算机工程与应用,2011,47(3):125-128.NING J,ZHU C Q,GAO P X,et al.Study on extension method of endpoint data in EMD decomposition[J].Computer engineering and applications,2011,47(3):125-128.
[16]杨航,郭晓金.一种改善EMD端点问题的方法[J].计算机工程与应用,2016,52(8):266-270.YANG H,GUO X J.A method to improve EMD endpoint problem[J].Computer engineering and applications,2016,52(8):266-270.
[17]许宝杰,张建民,徐小力,等.抑制EMD端点效应方法的研究[J].北京理工大学学报,2006,26(3):196-200.XU B J,ZHANG J M,XU X L,et al.Research on methods of suppressing EMD endpoint effect[J].Journal of Beijing Institute of Technology,2006,26(3):196-200.
[18]张洋,王健琪,荆西京,等.HHT在生物雷达回波信号噪声抑制中的应用[J].医疗卫生装备,2012,33(5):14-17.ZHANG Y,WANG J Q,JING X J,et al.Application of HHT in noise suppression of bio-radar echo signal[J].Medical equipment,2012,33(5):14-17.