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51.
介绍了时间域拉东正反变换的基本原理及该项技术在地震数据处理中的应用。以Ng和Perz的算法为基础,以开发地震勘探处理与解释系统为实例,解决了实验中遇到的拉东正变换时收敛精度、反变换数据无损还原和截断信号引起的能量扩散、低信噪比情况下的滤波等问题,进一步研究了改进算法在其他地形下应用问题。 相似文献
52.
由于随机噪声是一种频带较宽的干扰波,因此依靠单一的去噪处理方式往往难以获得清晰反映目标体的地震信息。小波变换能够较好的去除高斯噪声,保留有效波中、高频成分,提高记录的信噪比,但去除脉冲噪声的效果却并不理想;中值滤波具有良好的边缘保持特性,虽低频去噪声效果有限,但去除脉冲噪声效果明显。因此可利用二维小波变换与中值滤波优势互补的方法,进行叠前去噪处理,达到去除宽频随机噪声的目的。首先运用二维小波变换的理论,采用自适应门限阀值方法进行去噪,同时结合中值滤波方法联合去噪。模型与实际数据的应用效果表明,联合去噪方法可有效压制噪声能量、保留高频有效信号、提高地震记录信噪比与分辨率。 相似文献
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Analysis of characteristics of time-frequency correlations between runoff, tidal range and salinity in the Changjiang Estuary 总被引:2,自引:0,他引:2
Power spectrum and cross-wavelet transform analysis was adopted to study the time-frequency characteristics and multiscale correlations between runoff, tidal range and salinity in the Changjiang Estuary based on the runoff data collected at the Datong Station, the tidal range measured at the Baozhen Station, and the salinity at the Baogang Station from 2008 to 2009. The variations of the salinity showed significant periodicity at scales of 2-3, 7-8, 14-15 and 26-30 d. The correlation between the salinity and the runoff and the tidal range were found to be significantly related to shock at scales of 5-7, 14-15, 26-30 d and 0.5 a. The correlation between the runoff and the salinity was mainly in the same phase, while the correlation between the tidal range and the salinity was in the antiphase. Different frequency bands were related to different degrees, and their relevance increased as the resonance frequency decreased. In addition, changes of the seasonal runoff were obvious. Specifically, a point of discontinuity was reached in early June with a cycle of 7-8 d, which coincided with the periodicity of plum rains in the Changjiang-Huaihe region. High-frequency changes (8-16 d period) of the salinity corresponded to the time domain in January-April 2008, February-April 2009 and October-December 2009 and exhibited an approximately 0.5 a (184 d) long frequency oscillation. Short-period changes were found to be stronger than long-period changes. Cross-wavelet transforms for the salinity, the runoff and the tidal range revealed local features in the time domain, while the significant levels of different periodic oscillations were observed in the frequency domain. The correlation characteristics of the salinity and the runoff were significant in the 80-90 d frequency domain, indicating that the major impact of the runoff on the salinity was reflected in seasonal changes. The tidal range on the small scale of 14-15 and 30-32 d was more obvious than the runoff. 相似文献
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Separation of obliquely incident and reflected irregular waves by the Morlet wavelet transform 总被引:1,自引:0,他引:1
An existing 2D time-domain method for separating irregular incident and reflected waves by wavelet transform [Ma et al., 2010. A new method for separation of 2D incident and reflected waves by the Morlet wavelet transform. Coastal Eng., 57(6):597–603] is extended to account for obliquely incident irregular waves propagating over sloping bottoms. The linear shoaling and refraction coefficients are adopted to determine the amplitude and phase changes of waves. The optimal central frequency of the Morlet wavelet is determined by the minimum Shannon wavelet entropy. Numerical tests show that the present method can accurately separate waves over horizontal depths. For waves at sloping bottoms, however, the separation errors increase as bottom slope increases and are significant for waves with incident angle larger than π/3. 相似文献
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利用3s技术强大的空间信息处理和管理能力及制图能力,实现了在海南省海岸保护利用规划中多源地理数据采集处理、专题信息分析提取、规划图集编制和规划信息管理系统的建立等.结果表明:采用3S技术能够较好地处理海南省海岸保护利用规划中涉及的陆图、海图、遥感图、海洋功能区图、相关规划图和项目用海图等基础地理数据,以及现场调查、勘测数据的空间位置关系;提取了海南岛海岸类型、海岸开发利用现状等专题信息;结合海南社会经济发展对海岸资源开发利用的需求和生态环境保护要求,划分基本功能岸段,总体为北部海岸以港口、旅游岸段为主,东部海岸以旅游、渔业岸段为主,南部海岸以旅游、港口岸段为主,西部海岸以港口、渔业岸段为主. 相似文献
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