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Quantization-Based Robust Image Watermarking Using the Dual Tree Complex Wavelet Transform 被引量:4
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作者 LIU Jinhua SHE Kun 《China Communications》 SCIE CSCD 2010年第4期1-6,共6页
Conventional quantization index modulation (QIM) watermarking uses the fixed quantization step size for the host signal.This scheme is not robust against geometric distortions and may lead to poor fidelity in some are... Conventional quantization index modulation (QIM) watermarking uses the fixed quantization step size for the host signal.This scheme is not robust against geometric distortions and may lead to poor fidelity in some areas of content.Thus,we proposed a quantization-based image watermarking in the dual tree complex wavelet domain.We took advantages of the dual tree complex wavelets (perfect reconstruction,approximate shift invariance,and directional selectivity).For the case of watermark detecting,the probability of false alarm and probability of false negative were exploited and verified by simulation.Experimental results demonstrate that the proposed method is robust against JPEG compression,additive white Gaussian noise (AWGN),and some kinds of geometric attacks such as scaling,rotation,etc. 展开更多
关键词 Image Watermarking Quantization IndexModulation dual tree complex wavelet transform JPEG Compression
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Insect recognition based on integrated region matching and dual tree complex wavelet transform 被引量:2
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作者 Le-qing ZHU Zhen ZHANG 《Journal of Zhejiang University-Science C(Computers and Electronics)》 SCIE EI 2011年第1期44-53,共10页
To provide pest technicians with a convenient way to recognize insects,a novel method is proposed to classify insect images by integrated region matching (IRM) and dual tree complex wavelet transform (DTCWT).The wing ... To provide pest technicians with a convenient way to recognize insects,a novel method is proposed to classify insect images by integrated region matching (IRM) and dual tree complex wavelet transform (DTCWT).The wing image of the lepidopteran insect is preprocessed to obtain the region of interest (ROI) whose position is then calibrated.The ROI is first segmented with the k-means algorithm into regions according to the color features,properties of all the segmented regions being used as a coarse level feature.The color image is then converted to a grayscale image,where DTCWT features are extracted as a fine level feature.The IRM scheme is undertaken to find K nearest neighbors (KNNs),out of which the nearest neighbor is searched by computing the Canberra distance of DTCWT features.The method was tested with a database including 100 lepidopteran insect species from 18 families and the recognition accuracy was 84.47%.For the forewing subset,a recognition accuracy of 92.38% was achieved.The results showed that the proposed method can effectively solve the problem of automatic species identification of lepidopteran specimens. 展开更多
关键词 Lepidopteran insects Auto-classification k-means algorithm Integrated region matching (IRM) dual tree complex wavelet transform (DTCWT)
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A Dual Tree Complex Discrete Cosine Harmonic Wavelet Transform (ADCHWT) and Its Application to Signal/Image Denoising 被引量:3
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作者 M. Shivamurti S. V. Narasimhan 《Journal of Signal and Information Processing》 2011年第3期218-226,共9页
A new simple and efficient dual tree analytic wavelet transform based on Discrete Cosine Harmonic Wavelet Transform DCHWT (ADCHWT) has been proposed and is applied for signal and image denoising. The analytic DCHWT ha... A new simple and efficient dual tree analytic wavelet transform based on Discrete Cosine Harmonic Wavelet Transform DCHWT (ADCHWT) has been proposed and is applied for signal and image denoising. The analytic DCHWT has been realized by applying DCHWT to the original signal and its Hilbert transform. The shift invariance and the envelope extraction properties of the ADCHWT have been found to be very effective in denoising speech and image signals, compared to that of DCHWT. 展开更多
关键词 ANALYTIC DISCRETE COSINE Harmonic wavelet transform ANALYTIC wavelet transform dual tree complex wavelet transform DCT Shift Invariant wavelet transform wavelet transform Denoising
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Image inpainting using complex 2-D dual-tree wavelet transform
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作者 YANG Jian-bin 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2011年第1期70-76,共7页
The dual-tree complex wavelet transform is a useful tool in signal and image process- ing. In this paper, we propose a dual-tree complex wavelet transform (CWT) based algorithm for image inpalnting problem. Our appr... The dual-tree complex wavelet transform is a useful tool in signal and image process- ing. In this paper, we propose a dual-tree complex wavelet transform (CWT) based algorithm for image inpalnting problem. Our approach is based on Cai, Chan, Shen and Shen's framelet-based algorithm. The complex wavelet transform outperforms the standard real wavelet transform in the sense of shift-invariance, directionality and anti-aliasing. Numerical results illustrate the good performance of our algorithm. 展开更多
关键词 Image inpainting dual-tree complex wavelet transform wavelet shrinkage method.
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Seismic signal analysis based on the dual-tree complex wavelet packet transform
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作者 XIE Zhou-min(谢周敏) WANG En-fu(王恩福) +2 位作者 ZHANG Guo-hong(张国宏) ZHAO Guo-cun(赵国存) CHEN Xu-geng(陈旭庚) 《Acta Seismologica Sinica(English Edition)》 CSCD 2004年第z1期117-122,共6页
We tried to apply the dual-tree complex wavelet packet transform in seismic signal analysis. The complex wavelet packet transform (CWPT) combine the merits of real wavelet packet transform with that of complex contin... We tried to apply the dual-tree complex wavelet packet transform in seismic signal analysis. The complex wavelet packet transform (CWPT) combine the merits of real wavelet packet transform with that of complex continuous wavelet transform (CCWT). It can not only pick up the phase information of signal, but also produce better ″focal- izing″ function if it matches the phase spectrum of signals analyzed. We here described the dual-tree CWPT algo- rithm, and gave the examples of simulation and actual seismic signals analysis. As shown by our results, the dual-tree CWPT is a very effective method in analyzing seismic signals with non-linear phase. 展开更多
关键词 dual-tree complex wavelet packet transform instantaneous characteristics seismicsignalanalysis
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Defects Recognition of 3D Braided Composite Based on Dual-Tree Complex Wavelet Packet Transform
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作者 贺晓丽 王瑞 《Journal of Donghua University(English Edition)》 EI CAS 2015年第5期749-752,共4页
Textile-reinforced composites,due to their excellent highstrength-to-low-mass ratio, provide promising alternatives to conventional structural materials in many high-tech sectors. 3D braided composites are a kind of a... Textile-reinforced composites,due to their excellent highstrength-to-low-mass ratio, provide promising alternatives to conventional structural materials in many high-tech sectors. 3D braided composites are a kind of advanced composites reinforced with 3D braided fabrics; the complex nature of 3D braided composites makes the evaluation of the quality of the product very difficult. In this investigation,a defect recognition platform for 3D braided composites evaluation was constructed based on dual-tree complex wavelet packet transform( DT-CWPT) and backpropagation( BP) neural networks. The defects in 3D braided composite materials were probed and detected by an ultrasonic sensing system. DT-CWPT method was used to analyze the ultrasonic scanning pulse signals,and the feature vectors of these signals were extracted into the BP neural networks as samples. The type of defects was identified and recognized with the characteristic ultrasonic wave spectra. The position of defects for the test samples can be determined at the same time. This method would have great potential to evaluate the quality of 3D braided composites. 展开更多
关键词 3D braided composite dual-tree complex wavelet packet transform(DT-CWPT) ultrasonic wave
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A Complex Wavelet Transform Approach for 1 Dimensional Signal
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作者 Mukund Gokhale Daljeet Kaur Khanduja 《通讯和计算机(中英文版)》 2010年第8期62-72,共11页
关键词 复小波变换 信号途径 一维 离散小波变换 小波滤波器 平移不变性 复杂系数 标准制定
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Recognition of Group Activities Using Complex Wavelet Domain Based Cayley-Klein Metric Learning
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作者 Gensheng Hu Min Li +2 位作者 Dong Liang Mingzhu Wan Wenxia Bao 《Journal of Beijing Institute of Technology》 EI CAS 2018年第4期592-603,共12页
A group activity recognition algorithm is proposed to improve the recognition accuracy in video surveillance by using complex wavelet domain based Cayley-Klein metric learning.Non-sampled dual-tree complex wavelet pac... A group activity recognition algorithm is proposed to improve the recognition accuracy in video surveillance by using complex wavelet domain based Cayley-Klein metric learning.Non-sampled dual-tree complex wavelet packet transform(NS-DTCWPT)is used to decompose the human images in videos into multi-scale and multi-resolution.An improved local binary pattern(ILBP)and an inner-distance shape context(IDSC)combined with bag-of-words model is adopted to extract the decomposed high and low frequency coefficient features.The extracted coefficient features of the training samples are used to optimize Cayley-Klein metric matrix by solving a nonlinear optimization problem.The group activities in videos are recognized by using the method of feature extraction and Cayley-Klein metric learning.Experimental results on behave video set,group activity video set,and self-built video set show that the proposed algorithm has higher recognition accuracy than the existing algorithms. 展开更多
关键词 video surveillance group activity recognition non-sampled dual-tree complex wavelet packet transform(NS-DTCWPT) Cayley-Klein metric learning
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Tracking of Non-Rigid Object in Complex Wavelet Domain
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作者 Om Prakash Ashish Khare 《Journal of Signal and Information Processing》 2011年第2期105-111,共7页
In this paper we have proposed an object tracking method using Dual Tree Complex Wavelet Transform (DTCxWT). The proposed method is capable of tracking the moving object in video sequences. The object is assumed to be... In this paper we have proposed an object tracking method using Dual Tree Complex Wavelet Transform (DTCxWT). The proposed method is capable of tracking the moving object in video sequences. The object is assumed to be deform-able under limit i.e. it may change its shape from one frame to another. The basic idea in the proposed method is to decompose the image into two components: a two dimensional motion and a two dimensional shape change. The motion component is factored out while the shape is explicitly represented by storing a sequence of two dimensional models. Each model corresponds to each image frame. The proposed method performs well when the change in the shape in the consecutive frames is small however the 2-D motion in consecutive frames may be large. The proposed algorithm is capable of handling the partial as well as full occlusion of the object. 展开更多
关键词 Object TRACKING dual tree complex wavelet transform Model Based TRACKING BIORTHOGONAL FILTERS
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Pixel level image fusion scheme based on accumulated gradient and PCA transform 被引量:1
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作者 LI Bo L V Hai-lian 《通讯和计算机(中英文版)》 2009年第2期49-54,共6页
关键词 图像融合方法 梯度 双树复小波变换 图像处理
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基于强化双树复小波包变换的风电机组偏航轴承损伤识别 被引量:2
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作者 王晓龙 金韩微 +3 位作者 张博文 石海超 杨秀彬 何玉灵 《动力工程学报》 北大核心 2025年第1期115-123,共9页
针对风电机组偏航轴承损伤识别问题,提出了基于强化双树复小波包变换的损伤识别方法。首先,通过双树复小波包变换与线性峭度结合对不同分解层数下的分量计算平均线性峭度值,确定最优分解层数;其次,对最优分解所得小波系数及尺度系数进... 针对风电机组偏航轴承损伤识别问题,提出了基于强化双树复小波包变换的损伤识别方法。首先,通过双树复小波包变换与线性峭度结合对不同分解层数下的分量计算平均线性峭度值,确定最优分解层数;其次,对最优分解所得小波系数及尺度系数进行幅值调制,进而增强不同信号成分的能量;然后,采用散布熵指标确定各分量最佳调制系数并通过双树复小波包逆变换得到修正信号;最后,对修正信号作归一化平方包络谱分析提取故障特征频率。结果表明:所提方法能够实现复杂工况下偏航轴承损伤类型的准确识别,具有一定工程参考价值。 展开更多
关键词 风电机组 偏航轴承 双树复小波包变换 谱幅值调制
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基于双树复小波变换与稀疏表示的牙隐裂OCT三维图像融合 被引量:2
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作者 石博雅 董潇阳 《天津工业大学学报》 北大核心 2025年第1期62-68,共7页
针对采用光学相干层析(OCT)技术进行体积较大的前磨牙和磨牙的隐裂检测时,仅从单一扫描视角采集可能存在误检或漏检的问题,提出一种双树复小波变换(DTCWT)与稀疏表示(SR)相结合的牙隐裂三维图像融合方法。利用扫频OCT对人工牙隐裂模型从... 针对采用光学相干层析(OCT)技术进行体积较大的前磨牙和磨牙的隐裂检测时,仅从单一扫描视角采集可能存在误检或漏检的问题,提出一种双树复小波变换(DTCWT)与稀疏表示(SR)相结合的牙隐裂三维图像融合方法。利用扫频OCT对人工牙隐裂模型从2个扫描视角进行成像,经过三维图像配准后,利用双树复小波变换对图像进行分解。对于低频子带进行稀疏表示,采用“最大L1范数”规则进行融合,高频子带采用“绝对最大”规则融合,最后通过DTCWT重构得到融合后的图像。实验结果表明:采用本文方法融合后的牙隐裂图像可以得到裂纹的完整信息,获得准确的定位和分级,各方面性能均优于单独采用各多尺度分解方法和稀疏表示方法,标准差(SD)、平均梯度(AG)、空间频率(SF)和边缘信息评价因子(Q)的值分别平均提高到36.7、6.0、27.9和0.74,有效提高了OCT牙隐裂检测的准确性。 展开更多
关键词 牙隐裂 光学相干层析 稀疏表示 双树复小波变换
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基于自适应谱平均峭度图的轮对轴承故障诊断方法研究
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作者 何勇 岳新鹏 王红 《铁道科学与工程学报》 北大核心 2025年第11期5194-5204,共11页
针对轮对轴承早期故障所产生的微弱周期性冲击成分极易淹没在轮轨激励所产生的复杂背景噪声之中,进而使其早期故障特征难以有效提取的问题,提出一种基于自适应谱平均峭度图的轮对轴承故障诊断方法。该方法首先通过双树复小波包变换对原... 针对轮对轴承早期故障所产生的微弱周期性冲击成分极易淹没在轮轨激励所产生的复杂背景噪声之中,进而使其早期故障特征难以有效提取的问题,提出一种基于自适应谱平均峭度图的轮对轴承故障诊断方法。该方法首先通过双树复小波包变换对原始信号进行分解以得到不同分解层数下的一系列节点信号;其次,对节点信号的时域波形取绝对值并通过希尔伯特变换计算其包络,以避免该节点信号时域波形中局部极大值聚集对其子片段分割的影响;再次,将与节点信号包络各局部极大值最接近的局部极小值作为子片段的分割边界,并将不同子片段分割数量下计算得到的一系列平均峭度记为初始平均峭度;然后,取各节点信号所有初始平均峭度中的最大值记为其自适应平均峭度;最后,将所有节点信号中与最大自适应平均峭度相对应的节点信号作为最佳节点并对其进行包络谱分析。分别采用小比例转向架试验台数据及全尺寸货车轮对轴承试验数据对本文所提方法的有效性进行验证。案例分析结果表明,本文所提方法可以清晰地识别出轴承的理论故障频率并同时观察到更多的倍频成分,从而在强背景噪声干扰下自适应地诊断出轮对轴承的故障类型。综上所述,所提方法在提取轮对轴承故障特征及其倍频成分的数量上有着明显优势,具有一定的工程应用价值。 展开更多
关键词 自适应平均峭度 双树复小波包变换 滚动轴承 包络分析 故障诊断
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基于双树复小波变换的探地雷达图像随机噪音压制方法研究
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作者 施烨辉 黄月馨 沈宇鹏 《信息技术》 2025年第11期22-27,共6页
工程探测中,高分辨率的探地雷达信号容易受到随机噪音干扰,有效信号常被淹没在随机噪音中。传统的基于傅里叶变换滤波的噪音压制方法对频带分布较广的随机噪音压制效果较差,具备时频分析特性的小波变换噪音压制会造成信号高频失真。针... 工程探测中,高分辨率的探地雷达信号容易受到随机噪音干扰,有效信号常被淹没在随机噪音中。传统的基于傅里叶变换滤波的噪音压制方法对频带分布较广的随机噪音压制效果较差,具备时频分析特性的小波变换噪音压制会造成信号高频失真。针对这些问题,文中对比分析了双树复小波变换在移位差异特性和方向性特性上的优异性能,通过边缘测试和图像去噪分析测试,证明了双树复小波变换在随机噪音压制中的优势。将双树复小波变换去噪方法应用于探地雷达模拟和实测数据随机噪音压制中,取得了较好的去噪效果。 展开更多
关键词 双树复小波变换 噪音压制 探地雷达信号 图像去噪 峰值信噪比
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基于共振解调新方法的滚动轴承故障诊断
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作者 冯思茜 王家序 +1 位作者 张新 黄欣玥 《中国机械工程》 北大核心 2025年第9期2022-2031,共10页
为实现滚动轴承微弱特征提取与故障诊断,提出了一种基于子带重构重排-双树复小波包变换(SRR-DTCWPT)与峰值频率提取的共振解调新方法。基于SRR-DTCWPT的频带划分方法较为精细,并且在保持DTCWPT近似平移不变性和谱能量泄漏少的优点的同... 为实现滚动轴承微弱特征提取与故障诊断,提出了一种基于子带重构重排-双树复小波包变换(SRR-DTCWPT)与峰值频率提取的共振解调新方法。基于SRR-DTCWPT的频带划分方法较为精细,并且在保持DTCWPT近似平移不变性和谱能量泄漏少的优点的同时解决了频带错乱的问题。基于SRR-DTCWPT与峰值频率提取的共振解调方法不需要任何指标参与,能提取任意位置的频带,避免了强冲击干扰的影响,且计算过程自动化。将所提方法与Fast Kurtogram和Autogram算法进行比较,验证了该方法在滚动轴承故障诊断中的有效性与高效性。 展开更多
关键词 轴承故障诊断 共振解调 双树复小波包变换 子带重构重排 峰值频率提取
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基于双树复小波和深度信念网络的轴承故障诊断 被引量:32
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作者 张淑清 胡永涛 +3 位作者 姜安琦 李军锋 宿新爽 姜万录 《中国机械工程》 EI CAS CSCD 北大核心 2017年第5期532-536,543,共6页
提出了一种基于双树复小波(DTCWT)和深度信念网络(DBN)的轴承故障诊断新方法。采用DTCWT对轴承振动信号进行分解实验,结果表明DTCWT能够很好地将信号分解到不同频带。进而提取能量熵作为故障特征,采用DBN小样本分类模型对轴承故障进行分... 提出了一种基于双树复小波(DTCWT)和深度信念网络(DBN)的轴承故障诊断新方法。采用DTCWT对轴承振动信号进行分解实验,结果表明DTCWT能够很好地将信号分解到不同频带。进而提取能量熵作为故障特征,采用DBN小样本分类模型对轴承故障进行分类,并与传统分类器进行比较,结果表明该方法能准确识别不同故障类型,扩展了DBN在机械故障诊断中的应用。 展开更多
关键词 双树复小波 深度信念网络 受限波尔兹曼机 故障诊断
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双树复小波和奇异差分谱在滚动轴承故障诊断中的应用 被引量:19
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作者 胥永刚 孟志鹏 +1 位作者 陆明 付胜 《振动工程学报》 EI CSCD 北大核心 2013年第6期965-973,共9页
针对滚动轴承故障振动信号中包含强烈噪声,很难提取故障特征频率的情况,提出了基于双树复小波和奇异差分谱的故障诊断方法。首先利用双树复小波将非平稳振动信号分解为几个不同频段的分量;然后对包含故障特征的分量构建Hankel矩阵并进... 针对滚动轴承故障振动信号中包含强烈噪声,很难提取故障特征频率的情况,提出了基于双树复小波和奇异差分谱的故障诊断方法。首先利用双树复小波将非平稳振动信号分解为几个不同频段的分量;然后对包含故障特征的分量构建Hankel矩阵并进行奇异值分解,求奇异值差分谱曲线,根据奇异值差分谱最大突变点来确定奇异值个数进行重构;最后再求希尔伯特包络谱,便能准确地得到故障频率。实验结果和工程应用表明,该方法可以有效地提取轴承故障的故障信息,提取出了故障特征,验证了方法的可行性和有效性。 展开更多
关键词 故障诊断 滚动轴承 双树复小波 HANKEL矩阵 奇异差分谱
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基于局部熵的量子衍生医学超声图像去斑 被引量:13
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作者 付晓薇 代芸 +2 位作者 陈黎 田菁 丁胜 《电子与信息学报》 EI CSCD 北大核心 2015年第3期560-566,共7页
针对现有医学超声图像去斑方法的不足,该文提出一种基于局部熵的量子衍生医学超声图像去斑新方法。首先,将对数变换后的图像进行双树复小波变换(DTCWT),并对信号与噪声分别建模;然后,提取复小波中子代与父代小波系数的实部,计算其局部... 针对现有医学超声图像去斑方法的不足,该文提出一种基于局部熵的量子衍生医学超声图像去斑新方法。首先,将对数变换后的图像进行双树复小波变换(DTCWT),并对信号与噪声分别建模;然后,提取复小波中子代与父代小波系数的实部,计算其局部熵并进行归一化乘积,结合量子衍生理论得到用来调整信号与噪声出现概率的可调参数;最后,利用改进的双变量收缩函数获得去斑后的图像。通过实验,结果表明该方法与已有方法相比能够更有效地滤除医学超声图像中的斑点噪声并保留细节信息。 展开更多
关键词 图像处理 局部熵 量子衍生 双树复小波变换 双变量收缩
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双树复小波域隐Markov树模型降噪及在机械故障诊断中的应用 被引量:13
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作者 苏文胜 王奉涛 +3 位作者 朱泓 张志新 李宏坤 郭正刚 《振动与冲击》 EI CSCD 北大核心 2011年第6期47-52,共6页
提出一种基于双树复小波变换的隐Markov树模型的信号降噪方法,并将其成功应用于机械故障诊断中。机械设备的振动信号中不可避免地存在着噪声,使得微弱故障信息的提取一直是故障诊断的难点和热点。双树复小波变换具有近似平移不变性,而隐... 提出一种基于双树复小波变换的隐Markov树模型的信号降噪方法,并将其成功应用于机械故障诊断中。机械设备的振动信号中不可避免地存在着噪声,使得微弱故障信息的提取一直是故障诊断的难点和热点。双树复小波变换具有近似平移不变性,而隐Markov树模型能有效刻画小波系数间的相关性和非高斯性,两种优势的结合可以获得比常规软、硬阈值小波降噪法和小波域隐Markov树模型降噪法更好的降噪效果。它不仅能有效抑制高斯白噪声,还能够去除异常冲击干扰,仿真信号验证了这一点。对于实际滚动轴承信号,使用该方法同样可以获得满意的结果。 展开更多
关键词 双树复小波变换 隐马尔可夫树模型 降噪 故障诊断
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地震信号随机噪声压制的双树复小波域双变量方法 被引量:15
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作者 汪金菊 袁力 +1 位作者 刘婉如 徐小红 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2016年第8期3046-3055,共10页
有效地压制地震信号中的噪声是地震信号解释和后续处理的重要环节之一.本文建立两种双树复小波域双变量模型对地震信号中的随机噪声进行压制.地震信号经双树复小波变换后,同一方向实部与虚部系数、实部(或虚部)系数与对应的模之间存在... 有效地压制地震信号中的噪声是地震信号解释和后续处理的重要环节之一.本文建立两种双树复小波域双变量模型对地震信号中的随机噪声进行压制.地震信号经双树复小波变换后,同一方向实部与虚部系数、实部(或虚部)系数与对应的模之间存在较强的相关性.鉴于此,对同一方向实部与虚部小波系数建立双变量模型,从含噪地震信号小波系数中估计原始信号的小波系数,再基于双树复小波逆变换重构得到降噪后的地震信号.进一步对同一方向实部(或虚部)系数与对应的模建立双变量模型,得到地震信号随机噪声压制的第二种双树复小波域双变量方法.最后对合成地震记录和实际地震资料中的随机噪声进行压制的实验结果证实本文两种方法都能够有效地压制地震信号中的随机噪声. 展开更多
关键词 双树复小波变换 随机噪声 双变量模型 小波系数
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