基于EMD的激光雷达信号去噪方法
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摘要
针对激光雷达回波信号较弱易于被各种噪声污染的特点,本文提出利用经验模态来模态分解(EMD)这一非线性、非平稳信号处理方法,对Mie散射激光雷达信号进行多尺度分解。该方法是利用信号内部时间尺度的变化做能量与频率的解析,采用这种方法能够将噪声污染的激光雷达信号分解成若干个线性、稳态的本征函数(IMF),通过对本征函数的重构,去除包含高频噪声的IMFs,从而达到去噪目的。实验结果表明,这种方法的去噪能力强,并且具有自适应的特点,从而说明了这种方法在信号去噪中的优势。
In view of lidar return signal easily polluted by various noises, a new method of Empirical Mode Decomposition (EMD) that can analyze the nonlinear and non-stationary signal is introduced to decompose lidar signal. The method based on signal intrinsic time scales is used to extract the energy and frequency of signal. With the method, the Mie lidar signal polluted by noises is decomposed into a number of Intrinsic Mode Function (IMF). In the reconstruction course of IMFs, the IMFs including high-frequency noise are excluded to reduce the noise. The experiment results demonstrate that the method has powerful and adaptive de-noising ability. To denoise Mie lidar signal by using the method has been attempted. It is believed that the method can provide a new effective way of noise reduction for weak lidar signal.
In view of lidar return signal easily polluted by various noises, a new method of Empirical Mode Decomposition (EMD) that can analyze the nonlinear and non-stationary signal is introduced to decompose lidar signal. The method based on signal intrinsic time scales is used to extract the energy and frequency of signal. With the method, the Mie lidar signal polluted by noises is decomposed into a number of Intrinsic Mode Function (IMF). In the reconstruction course of IMFs, the IMFs including high-frequency noise are excluded to reduce the noise. The experiment results demonstrate that the method has powerful and adaptive de-noising ability. To denoise Mie lidar signal by using the method has been attempted. It is believed that the method can provide a new effective way of noise reduction for weak lidar signal.
引文
[1]Fang Hai-tao,Huang De-shuang.Lidar signal de-noising based on wavelet trimmed thresholding technique[J].Chines Optics letters,2004,2(1):1-3.
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[4]Huang N E,Shen Z,Long S R,et al.The Empirical Mode decomposition and Hilbert Spectrum for nonlinear and nonstationary time series analysis[J].Proceedings of the Royal Society of London:A,1998,454:903-995.
[5]李强,吴健,许正文,等.利用EMD方法提取太阳活动周期成分[J].空间科学学报,2007,27(1):1-6.LI Qiang,WU jian,XU Zheng-wen,et al.Extraction of periodic components in the solar activity using EMD method[J].Chinese Journal of Space Science,2007,27(1):1-6.
[6]李永勤,王清,邓亲恺.EMD及其在生物医学信号处理中的应用研究[J].生物医学工程学杂志,2005,22(5):1058-1062.LI Yong-qin,WANG Qing,DENG Qin-kai.Research on EMD and its application in Biomedical signal processing[J].Journal of Biomedical Engineering,2005,22(5):1058-1062.
[7]罗忠辉,薛晓宁,王筱珍,等.小波变换及经验模态分解方法在电机轴承早期故障诊断中的应用[J].中国电机工程学报,2005,25(14):125-129.LUO Zhong-hui,XUE Xiao-ning,WANG Xiao-zhen,et al.Study on the method of incipient motor bearing fault diageosis based on wavelet transform and EMD[J].Proceeding of the CSEE,2005,25(14):125-129.
[8]陈子雄,吴琛,周瑞忠.希尔伯特-黄变换谱及其在地震信号分析中的应用[J].福州大学学报(自然科学版),2006,34(2):260-264.CHEN Zi-xiong,WU Chen,ZHOU Rui-zhong.Hilbert-Huang transform spectrum and its application in seismic signal analysis[J].J.Fuzhou University(Natural Science),2006,34(2):260-264.
[9]Huang N E,Chern CC,Huang K,et al.A new spectral representation of earthquake data:Hilbert spectral analysis of station TCU129,Chi-Chi,Taiwan,21September1999[J].Bulletin Of The Seismological Society Of America,2001,91(5):1310-1338.
[10]Lin Z S,Wang S G.EMD analysis of solar insolation[J].Meteorology and Atmospheric Physics,2006,93:123-128.
[2]Fang Hai-tao,Huang De-shuang.Noise reduction in lidar signal based on discrete wavelet transform[J].OptiticsCommunications,2004,233:67-76.
[3]Hwang P A,Huang N E,Wang D W.A note on analyzing nonlinear and nonstationary ocean wave data[J].Applied Ocean Research,2003,25:187-193.
[4]Huang N E,Shen Z,Long S R,et al.The Empirical Mode decomposition and Hilbert Spectrum for nonlinear and nonstationary time series analysis[J].Proceedings of the Royal Society of London:A,1998,454:903-995.
[5]李强,吴健,许正文,等.利用EMD方法提取太阳活动周期成分[J].空间科学学报,2007,27(1):1-6.LI Qiang,WU jian,XU Zheng-wen,et al.Extraction of periodic components in the solar activity using EMD method[J].Chinese Journal of Space Science,2007,27(1):1-6.
[6]李永勤,王清,邓亲恺.EMD及其在生物医学信号处理中的应用研究[J].生物医学工程学杂志,2005,22(5):1058-1062.LI Yong-qin,WANG Qing,DENG Qin-kai.Research on EMD and its application in Biomedical signal processing[J].Journal of Biomedical Engineering,2005,22(5):1058-1062.
[7]罗忠辉,薛晓宁,王筱珍,等.小波变换及经验模态分解方法在电机轴承早期故障诊断中的应用[J].中国电机工程学报,2005,25(14):125-129.LUO Zhong-hui,XUE Xiao-ning,WANG Xiao-zhen,et al.Study on the method of incipient motor bearing fault diageosis based on wavelet transform and EMD[J].Proceeding of the CSEE,2005,25(14):125-129.
[8]陈子雄,吴琛,周瑞忠.希尔伯特-黄变换谱及其在地震信号分析中的应用[J].福州大学学报(自然科学版),2006,34(2):260-264.CHEN Zi-xiong,WU Chen,ZHOU Rui-zhong.Hilbert-Huang transform spectrum and its application in seismic signal analysis[J].J.Fuzhou University(Natural Science),2006,34(2):260-264.
[9]Huang N E,Chern CC,Huang K,et al.A new spectral representation of earthquake data:Hilbert spectral analysis of station TCU129,Chi-Chi,Taiwan,21September1999[J].Bulletin Of The Seismological Society Of America,2001,91(5):1310-1338.
[10]Lin Z S,Wang S G.EMD analysis of solar insolation[J].Meteorology and Atmospheric Physics,2006,93:123-128.
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