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In this paper,the Raman spectrum signal de-noising based on stationary wavelet transform is discussed.Haar wavelet is selected to decompose the Raman spectrum signal for several levels based on stationarywavelet transform.The noise mean square σj is estimated by the wavelet details at every level,and thewavelet details toward 0 by a threshold σj √2lnn,where n is length of the detail,then recovery signalis reconstructed.Experimental results show this method not only suppresses noise effectively,but alsopreserves as many target characteristics of original signal as possible.This de-noising method offers a veryattractive alternative to Raman spectrum signal noise suppress. 相似文献
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In this paper, the Raman spectrum signal de-noising based on stationary wavelet transform is discussed. Haar wavelet is selected to decompose the Raman spectrum signal for several levels based on stationary wavelet transform. The noise mean square j is estimated by the wavelet details at every level, and the wavelet details toward 0 by a threshold , where n is length of the detail, then recovery signal is reconstructed. Experimental results show this method not only suppresses noise effectively, but also preserves as many target characteristics of original signal as possible. This de-noising method offers a very attractive alternative to Raman spectrum signal noise suppress. 相似文献
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分析了全电视信号PCM编码色度副载波量化噪声,并讨论了量化噪声与取样频率fs和量化比特数n的关系。 相似文献
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A novel and efficient speckle noise reduction algorithm based on Bayesian wavelet shrinkage using cycle spinning is proposed. First, the sub-band decompositions of non-logarithmically transformed SAR images are shown. Then, a Bayesian wavelet shrinkage factor is applied to the decomposed data to estimate noise-free wavelet coefficients. The method is based on the Mixture Gaussian Distributed (MGD) modeling of sub-band coefficients. Finally, multi-resolution wavelet coefficients are reconstructed by wavelet-threshold using cycle spinning. Experimental results show that the proposed despeclding algorithm is possible to achieve an excellent balance between suppresses speckle effectively and preserves as many image details and sharpness as possible. The new method indicated its higher performance than the other speckle noise reduction techniques and minimizing the effect of pseudo-Gibbs phenomena. 相似文献
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半连续Ag膜的多重分形研究 总被引:1,自引:0,他引:1
用透射电镜(TEM)观察了用直流磁控溅射法制备的厚度为1.5nm~67nm的半连续Ag膜的形貌,并用多重分形理论定量表征不同厚度半连续Ag膜中Ag小岛的面分布均匀性及其尺寸分布。结果显示:随着薄膜厚度的增加,多重分形谱的谱宽△a先增大后减小,在6nm~12nm之间出现最大值,表明薄膜中小岛的面分布均匀性是由均匀到不均匀再到均匀的变化过程;当薄膜厚度达到某一临界值(在12nm~67nm之间)时,△f,从〈0向〉0发生转变,此时薄膜中小岛的尺寸分布由较大程度上取决于体积最小的小岛向较大程度上取决于体积最大的小岛过渡。 相似文献
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基于平稳小波变换的心电信号噪声消除方法 总被引:34,自引:1,他引:34
本文针对小波空间适应法在心电信号消噪中的缺陷,提出一种利用平稳小波变换(Stationary Wavelet Transform)的心电信号消噪方法,对受噪声污染的心电信号进行多层平稳小波变换,逐层估计平稳小波变换细节信号中噪声的均方差σj,选取各层阈值σj 2lnn (n为细节信号长度),对平稳小波变换的各层细节信号进行分别阈值处理,然后进行小波逆变换重建信号,以达到对信号消噪和恢复的目的.这种方法可以很好的抑制小波空间适应法消噪出现的Gibbs现象,较好地保持了心电信号的几何特征. 相似文献
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