微地震资料的处理、解释首先需要拾取精确的初至信息。微地震初至的人工拾取虽然精度较高,但工作量大,不能满足实时处理的需要。为此,提出了一种基于小波多尺度分解和高阶统计量相结合的长短时窗峰度比(wavelet transform based short t...微地震资料的处理、解释首先需要拾取精确的初至信息。微地震初至的人工拾取虽然精度较高,但工作量大,不能满足实时处理的需要。为此,提出了一种基于小波多尺度分解和高阶统计量相结合的长短时窗峰度比(wavelet transform based short time window kurtosis/long time window kurtosis,W-STK/LTK)微地震初至拾取方法。考虑到有效微地震信号频率较低,而噪声信号频率则相对较高,首先对微地震信号进行小波多尺度分解,剥离有效信号与噪声;接着对分解得到的最大尺度信号应用基于高阶统计量的长短时窗峰度比(STK/LTK)算法;最后在分析特征曲线异常点特征的基础上识别微地震有效信号并拾取初至。模型数据和实际资料测试结果表明,该方法能够从信噪比较低的微地震资料中较准确地拾取微地震P波初至。展开更多
An adaptive approach to select analysis window param- eters for linear frequency modulated （LFM） signals is proposed to obtain the optimal 3 dB signal-to-noise ratio （SNR） in the short- time Fourier transform （S...An adaptive approach to select analysis window param- eters for linear frequency modulated （LFM） signals is proposed to obtain the optimal 3 dB signal-to-noise ratio （SNR） in the short- time Fourier transform （STFT） domain. After analyzing the instan- taneous frequency and instantaneous bandwidth to deduce the relation between the window length and deviation of the Gaus- sian window, high-order statistics is used to select the appropriate window length for STFT and get the optimal SNR with the right time-frequency resolution according to the signal characteristic under a fixed sampling rate. Computer simulations have verified the effectiveness of the new method.展开更多
文摘微地震资料的处理、解释首先需要拾取精确的初至信息。微地震初至的人工拾取虽然精度较高,但工作量大,不能满足实时处理的需要。为此,提出了一种基于小波多尺度分解和高阶统计量相结合的长短时窗峰度比(wavelet transform based short time window kurtosis/long time window kurtosis,W-STK/LTK)微地震初至拾取方法。考虑到有效微地震信号频率较低,而噪声信号频率则相对较高,首先对微地震信号进行小波多尺度分解,剥离有效信号与噪声;接着对分解得到的最大尺度信号应用基于高阶统计量的长短时窗峰度比(STK/LTK)算法;最后在分析特征曲线异常点特征的基础上识别微地震有效信号并拾取初至。模型数据和实际资料测试结果表明,该方法能够从信噪比较低的微地震资料中较准确地拾取微地震P波初至。
基金supported by the National Natural Science Foundation of China(6107313361175053+8 种基金6127236960975019)the Heilongjiang Postdoctoral Grant(LRB08362)the Fundamental Research Funds for the Central Universities of China(2011QN0272011QN1262012QN0302011ZD010)the Science and Technology Planning Project of Dalian City(2011A17GX0732010E15SF153)
文摘An adaptive approach to select analysis window param- eters for linear frequency modulated （LFM） signals is proposed to obtain the optimal 3 dB signal-to-noise ratio （SNR） in the short- time Fourier transform （STFT） domain. After analyzing the instan- taneous frequency and instantaneous bandwidth to deduce the relation between the window length and deviation of the Gaus- sian window, high-order statistics is used to select the appropriate window length for STFT and get the optimal SNR with the right time-frequency resolution according to the signal characteristic under a fixed sampling rate. Computer simulations have verified the effectiveness of the new method.
