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Fault Feature Extraction of Rotating Machinery Based on Wavelet Transformation and Multi-resolution Analysis
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作者 公茂法 刘庆雪 +1 位作者 刘明 张晓丽 《Journal of Measurement Science and Instrumentation》 CAS 2010年第4期312-314,共3页
This paper expounded in detail the principle of energy spectrum analysis based on discrete wavelet transformation and multiresolution analysis. In the aspect of feature extraction method study, with investigating the ... This paper expounded in detail the principle of energy spectrum analysis based on discrete wavelet transformation and multiresolution analysis. In the aspect of feature extraction method study, with investigating the feature of impact factor in vibration signals and considering the non-placidity and non-linear of vibration diagnosis signals, the authors import wavelet analysis and fractal theory as the tools of faulty signal feature description. Experimental results proved the validity of this method. To some extent, this method provides a good approach of resolving the wholesome problem of fault feature symptom description. 展开更多
关键词 discrete wavelet transform (DWT) multi-resolution analysis fault diagnosis rotating madchinery feature extraction
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Application of multi-resolution analysis in sonar image denoising 被引量:1
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作者 Shang Zhengguo Zhao Chunhui Wan Jian 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2008年第6期1082-1089,共8页
Sonar images have complex background, low contrast, and deteriorative edges; these characteristics make it difficult for researchers to dispose the sonar objects. The multi-resolution analysis represents the signals i... Sonar images have complex background, low contrast, and deteriorative edges; these characteristics make it difficult for researchers to dispose the sonar objects. The multi-resolution analysis represents the signals in different scales efficiently, which is widely used in image processing. Wavelets are successful in disposing point discontinuities in one dimension, but not in two dimensions. The finite Ridgelet transform (FRIT) deals efficiently with the singularity in high dimension. It presents three improved denoising approaches, which are based on FRIT and used in the sonar image disposal technique. By experiment and comparison with traditional methods, these approaches not only suppress the artifacts, but also obtain good effect in edge keeping and SNR of the sonar image denoising. 展开更多
关键词 multi-resolution analysis wavelet transform ridgelet transform cycle sample adaptive denoisingenergy delamination
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MULTI-RESOLUTION MOTION ESTIMATION AND COMPENSATION BASED ON ADJACENT PREDICTION OF FRAME DIFFERENCE IN WAVELET DOMAIN 被引量:3
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作者 Tang Guowei Gu Guochang 《Journal of Electronics(China)》 2009年第3期412-416,共5页
Aiming at the higher bit-rate occupation of motion vector encoding and more time load of full-searching strategies, a multi-resolution motion estimation and compensation algorithm based on adjacent prediction of frame... Aiming at the higher bit-rate occupation of motion vector encoding and more time load of full-searching strategies, a multi-resolution motion estimation and compensation algorithm based on adjacent prediction of frame difference was proposed.Differential motion detection was employed to image sequences and proper threshold was adopted to identify the connected region.Then the motion region was extracted to carry out motion estimation and motion compensation on it.The experiment results show that the encoding efficiency of motion vector is promoted, the complexity of motion estimation is reduced and the quality of the reconstruction image at the same bit-rate as Multi-Resolution Motion Estimation(MRME) is improved. 展开更多
关键词 wavelet transforms Motion estimation Motion compensation multi-resolution analysis Video coding
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Identification method of seismic phase in three-component seismograms on the basis of wavelet transform 被引量:4
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作者 刘希强 周惠兰 +3 位作者 沈萍 杨选辉 马延路 李红 《Acta Seismologica Sinica(English Edition)》 CSCD 2000年第2期136-142,共7页
This paper puts forward wavelet transform method to identify P and S phases in three component seismograms using polarization information contained in the wavelet transform coefficients of signal. The P and S wave loc... This paper puts forward wavelet transform method to identify P and S phases in three component seismograms using polarization information contained in the wavelet transform coefficients of signal. The P and S wave locator functions are constructed by using eigenvalue analysis method to wavelet transform coefficient across several scales. Locator functions formed by wavelet transform have stated noise resistance capability, and is proved to be very effective in identifying the P and S arrivals of the test data and actual earthquake data. 展开更多
关键词 wavelet transform eigenvalue analysis seismic phase identification
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Online Test and Fault Diagnosis of Yarn Quality Using Wavelet Analysis and FFT
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作者 洪锡军 邱浩波 +1 位作者 李昱明 李从心 《Journal of Donghua University(English Edition)》 EI CAS 2002年第2期99-102,共4页
A new online system of monitoring yarn quality and fault diagnosis is presented. This system integrates the technologies of sensor, signal process, communication, network, computer, control, instrument structure and m... A new online system of monitoring yarn quality and fault diagnosis is presented. This system integrates the technologies of sensor, signal process, communication, network, computer, control, instrument structure and mass knowledge of experts. Comparing with conventional off-line yarn test, the new system can find the quality defects of yarn online in time and compensate for the lack of expert knowledge in manual analysis. It can save a lot of yarn wasted in off-line test and improve product quality. By using laser sensor to sample the diameter signal of yarn and doing wavelet analysis and FFT to extract fault characteristics, a set of reasoning mechanism is established to analyze yarn quality and locate the fault origination. The experimental results show that new system can do well in monitoring yarn quality online comparing with conventional off-line yarn test. It can test the quality of yarn in real-time with high efficiency and analyze the fault reason accurately. It is very useful to apply this new system to upgrade yarn quality in cotton textile industry at present. 展开更多
关键词 wavelet transform multi-resolution analysis FFT FAULT Diagnosis ONLINE Test
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Multi-Focus Image Fusion Based on Wavelet Transformation 被引量:4
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作者 Peng Zhang Ying-Xun Tang +1 位作者 Yan-Hua Liang Xu-Bo Liu 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2013年第2期124-128,共5页
In the fusion of image,how to measure the local character and clarity is called activity measurement. According to the problem,the traditional measurement is decided only by the high-frequency detail coefficients, whi... In the fusion of image,how to measure the local character and clarity is called activity measurement. According to the problem,the traditional measurement is decided only by the high-frequency detail coefficients, which will make the energy expression insufficient to reflect the local clarity. Therefore,in this paper,a novel construction method for activity measurement is proposed. Firstly,it uses the wavelet decomposition for the fusion resource image, and then utilizes the high and low frequency wavelet coefficients synthetically. Meantime,it takes the normalized variance as the weight of high-frequency energy. Secondly,it calculates the measurement by the weighted energy,which can be used to measure the local character. Finally,the fusion coefficients can be got. In order to illustrate the superiority of this new method,three kinds of assessing indicators are provided. The experiment results show that,comparing with the traditional methods,this new method weakens the fuzzy and promotes the indicator value. Therefore,it has much more advantages for practical application. 展开更多
关键词 variance MEASURE image fusion wavelet transformation multi-resolution analysis
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Extraction of MHD Signal Based on Wavelet Transform
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作者 赵晴初 赵彤 +2 位作者 李旻 黄胜华 徐佩霞 《Plasma Science and Technology》 SCIE EI CAS CSCD 2002年第4期1367-1374,共8页
Mirnov signals mixed with interferences are a kind of non-stationary signal. It cannot obtain satisfactory effects to extract MHD signals from mirnov signals by Fourier Transform. This paper suggests that the wavelet ... Mirnov signals mixed with interferences are a kind of non-stationary signal. It cannot obtain satisfactory effects to extract MHD signals from mirnov signals by Fourier Transform. This paper suggests that the wavelet transform can be used to treat mirnov signals. Theoretical analysis and experimental result have indicated that using the time-frequency analysis characteristics of the wavelet transform to filter mirnov signals can remove effectively interferences and extract useful MHD signals. 展开更多
关键词 wavelet transform MHD time-frequency analysis multi-resolution analysis
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Novel Adaptive Beamforming Algorithm Based on Wavelet Packet Transform
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作者 张小飞 徐大专 《Journal of Southwest Jiaotong University(English Edition)》 2005年第1期28-34,共7页
An analysis of the received signal of array antennas shows that the received signal has multi-resolution characteristics, and hence the wavelet packet theory can be used to detect the signal. By emplying wavelet packe... An analysis of the received signal of array antennas shows that the received signal has multi-resolution characteristics, and hence the wavelet packet theory can be used to detect the signal. By emplying wavelet packet theory to adaptive beamforming, a wavelet packet transform-based adaptive beamforming algorithm (WP-ABF) is proposed . This WP-ABF algorithm uses wavelet packet transform as the preprocessing, and the wavelet packet transformed signal uses least mean square algorithm to implement the ~adaptive beamforming. White noise can be wiped off under wavelet packet transform according to the different characteristics of signal and white under the wavelet packet transform. Theoretical analysis and simulations demonstrate that the proposed WP-ABF algorithm converges faster than the conventional adaptive beamforming algorithm and the wavelet transform-based beamforming algorithm. Simulation results also reveal that the convergence of the algorithm relates closely to the wavelet base and series; that is, the algorithm convergence gets better with the increasing of series, and for the same series of wavelet base the convergence gets better with the increasing of regularity. 展开更多
关键词 Adaptive beamforming wavelet packet transform multi-resolution analysis Array signal processing
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Wavelets as Basis Functions in the Adaptation's Methods: Author's Model for Forecasting Short-Term
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作者 Monika Hadas-Dyduch 《Chinese Business Review》 2016年第1期8-17,共10页
The aim of this article is to present author's application of wavelets to predict short-term macroeconomic indicators Proposed to predict short-term time series (in particular for predicting macroeconomic indicators... The aim of this article is to present author's application of wavelets to predict short-term macroeconomic indicators Proposed to predict short-term time series (in particular for predicting macroeconomic indicators), proprietary model is based on wavelet analysis with Haar wavelets, Daubechies wavelets, and adaptive models; they are the trend crawling model and alignment exponential model. Adaptive models have been modified through the introduction of wavelet function and combined into a single forecast model. Obtained from conducted research results, it shows the model an effective instrument to predict the short-term. 展开更多
关键词 waveletS wavelet transform multi-resolution analysis PREDICTION macroeconomic indicators
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基于电容层析测量的油气两相流动态信号时频分析方法 被引量:1
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作者 徐一 李轶 +1 位作者 马志扬 王海刚 《化工进展》 EI CAS CSCD 北大核心 2024年第2期855-864,共10页
基于虚拟电容层析成像(electrical capacitance tomography,ECT)传感器和流电耦合仿真方法,本文动态模拟了4种典型的油气两相流流型及其相应的测量信号,并采用基于小波变换的多分辨率分析(multi-resolution analysis,MRA)和时频分析方... 基于虚拟电容层析成像(electrical capacitance tomography,ECT)传感器和流电耦合仿真方法,本文动态模拟了4种典型的油气两相流流型及其相应的测量信号,并采用基于小波变换的多分辨率分析(multi-resolution analysis,MRA)和时频分析方法对压力和电容的时间序列信号进行分析。连续小波变换显示了时频二维平面中的能量分布,并在时间上有效定位了瞬时流量波动。而基于小波MRA方法对流型变化下的原始测量信号进行不同频带的分解后,压力和电容测量信号的主导频率均呈现出由中频到低频再到高频的迁移规律,为流型识别提供了有效的量化判据。在间歇流实验测量中应用信号时频分析方法,有效解析了不同流量下段塞频率、流量波动和液塞形态的变化。本文的研究方法和研究结果有望为实际过程中的流型识别和过程监测提供可靠手段。 展开更多
关键词 电容层析成像 两相流 小波变换 多分辨率分析
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基于相位差时延估计法的岩石声发射源定位研究 被引量:18
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作者 黄晓红 张艳博 +1 位作者 田宝柱 刘祥鑫 《岩土力学》 EI CAS CSCD 北大核心 2015年第2期381-386,522,共7页
针对岩石力学试验声发射时差定位算法中时延估计精度受诸多不确定因素的影响问题,提出全相位相位差法时延估计,通过小波分解与全相位频谱分析相结合求解相位差得到声发射信号的时延估计。利用小波分解找到不同传感器接收到的声发射信号... 针对岩石力学试验声发射时差定位算法中时延估计精度受诸多不确定因素的影响问题,提出全相位相位差法时延估计,通过小波分解与全相位频谱分析相结合求解相位差得到声发射信号的时延估计。利用小波分解找到不同传感器接收到的声发射信号中的同一主频的子带信号;对这些同一主频的子带信号分别做全相位频谱分析,得到每个子带信号中间样点的相位,再根据相位差与时间差的关系求出声发射信号到达不同传感器之间的时间差;进而利用时差定位法反演声发射源,实现了声发射源更精确的定位。在花岗岩(50 mm×100 mm×50 mm)上进行断铅试验,选取10个测点,经声发射监测验证结果表明,该时延估计方法能有效地减小声发射源定位的误差,提高声发射源的定位精度,平均绝对误差比美国PCI-2型声发射仪器定位结果提高约3 mm,该方法为反演声发射源提供了一种有效途径。 展开更多
关键词 声发射 小波分解 全相位频谱分析 相位差 源定位
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条纹投影动态三维表面成像技术综述 被引量:15
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作者 李勇 张广汇 +2 位作者 马利红 应晓霖 姚建云 《红外与激光工程》 EI CSCD 北大核心 2020年第3期83-95,共13页
对条纹投影动态三维表面成像技术进行了总结,分析了典型方案的特点。首先介绍了该技术的基本原理,包括系统基本结构、三维表面成像原理及相移法和傅立叶变换法这两种典型的相位提取方法。接着介绍了动态成像方案,包括高速投影方案和采... 对条纹投影动态三维表面成像技术进行了总结,分析了典型方案的特点。首先介绍了该技术的基本原理,包括系统基本结构、三维表面成像原理及相移法和傅立叶变换法这两种典型的相位提取方法。接着介绍了动态成像方案,包括高速投影方案和采用速度相对低的相机进行动态三维表面成像的方案。然后介绍了动态三维成像中绝对相位获取方法,主要是模拟和数字编码法及区域统计特性编码法。最后介绍了高精度动态相位测量方案。 展开更多
关键词 光学三维成像 相位测量轮廓术 傅立叶变换轮廓术 条纹分析 绝对相位
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基于瞬时无功功率理论的电能质量扰动检测、定位与分类方法 被引量:68
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作者 魏磊 张伏生 +3 位作者 耿中行 张柏林 李宁 刘沛津 《电网技术》 EI CSCD 北大核心 2004年第6期53-58,共6页
提出了一种对电能质量扰动进行检测、定位、辨识与分类的有效方法。首先对含有噪声的信号进行小波去噪处理,得到信噪比较高的信号,再对去噪后的信号进行差变处理得到差变信号,通过小波去噪和信号差变法来确定扰动的位置和持续时间。将... 提出了一种对电能质量扰动进行检测、定位、辨识与分类的有效方法。首先对含有噪声的信号进行小波去噪处理,得到信噪比较高的信号,再对去噪后的信号进行差变处理得到差变信号,通过小波去噪和信号差变法来确定扰动的位置和持续时间。将去噪后的单相电压信号通过移相?60°得到三相电压,并用三相电压代替三相电流,利用瞬时无功功率理论计算出瞬时有功,进而计算出瞬时电压幅值,根据扰动的持续时间和扰动的幅度对扰动类型进行识别。 展开更多
关键词 电力系统 瞬时无功功率理论 电能质量扰动 检测 定位 分类
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采用小波脊系数幅值导数方差质量图的相位展开法 被引量:5
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作者 王勇 饶勤菲 +1 位作者 唐靖 袁巢燕 《光子学报》 EI CAS CSCD 北大核心 2015年第2期54-61,共8页
针对小波变换轮廓术中相位无法快速准确展开的问题,提出了一种能有效抑制噪音的相位展开算法.首先,分析了小波脊系数幅值质量图和相位导数方差质量图的特征;然后依据相位值与其数学期望的偏差程度,利用小波脊系数幅值矩阵和导数方差思... 针对小波变换轮廓术中相位无法快速准确展开的问题,提出了一种能有效抑制噪音的相位展开算法.首先,分析了小波脊系数幅值质量图和相位导数方差质量图的特征;然后依据相位值与其数学期望的偏差程度,利用小波脊系数幅值矩阵和导数方差思想构造了"小波脊系数幅值导数方差"质量图;最后分别进行软件仿真和真实模型实验,并将利用新质量图引导的相位展开效果与传统相位展开质量图法和改进的质量图法进行对比.实验结果表明,本文算法提高了相位展开精确度,相位展开误差率降低了2.61%.所提质量图易于构造,在引导相位展开时不仅能得到较准确的绝对相位值,还能有效抑制噪音的影响,从而重建出精确度高的物体三维模型. 展开更多
关键词 小波变换轮廓术 相位展开 小波脊系数幅值导数方差 质量图 相位噪音
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基于小波分析的傅里叶变换轮廓术应用研究 被引量:3
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作者 任旭虎 宋珊珊 綦耀光 《中国石油大学学报(自然科学版)》 EI CAS CSCD 北大核心 2007年第1期148-153,共6页
采用一种基于小波分析的傅里叶变换轮廓术测量了物体三维形貌。利用小波变化的时频特性,对测量光栅图像进行了处理,提取了有用的频率分量,获得了光栅图像的相位信息,抑制了频率混叠。计算机模拟结果验证了该方法的可行性,并在有噪声和... 采用一种基于小波分析的傅里叶变换轮廓术测量了物体三维形貌。利用小波变化的时频特性,对测量光栅图像进行了处理,提取了有用的频率分量,获得了光栅图像的相位信息,抑制了频率混叠。计算机模拟结果验证了该方法的可行性,并在有噪声和无噪声的情况下与一般数字滤波器处理结果进行了比较,无论从测量精度还是测量范围都得到了提高。 展开更多
关键词 傅里叶变换轮廓术 小波分析 相位解包裹 频率混叠
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基于时频分析的初至拾取方法研究 被引量:11
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作者 岳龙 刘怀山 +2 位作者 刘凯 徐秀刚 邢磊 《石油物探》 EI CSCD 北大核心 2015年第5期508-520,共13页
地震记录的初至拾取是地震资料处理的基础工作,特别是静校正、层析成像等后续处理对初至拾取的精度要求较高。当初至波到达时,其信号的振幅、频率、相位均会发生变化,基于此,提出了一种基于时频分析的初至拾取算法,该算法在噪声判别系... 地震记录的初至拾取是地震资料处理的基础工作,特别是静校正、层析成像等后续处理对初至拾取的精度要求较高。当初至波到达时,其信号的振幅、频率、相位均会发生变化,基于此,提出了一种基于时频分析的初至拾取算法,该算法在噪声判别系数的约束下,利用小波变换时频分析提取信号的瞬时相位谱,然后利用瞬时相位谱的过零点属性拾取初至。为了提高计算效率,在给定时窗内部计算信号的瞬时相位谱,并且利用多个不同的噪声判别系数初至拾取的统计结果确定最终的初至时间。理论信号和实际地震资料处理结果表明,该方法具有较好的抗噪能力,初至拾取的精度比较高。 展开更多
关键词 初至拾取 小波变换 时频分析 瞬时相位谱 噪声判别系数
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一种改进的加权最小二乘相位展开方法研究 被引量:4
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作者 殷爱菡 张清淼 姜辉明 《计算机工程与应用》 CSCD 2013年第3期159-162,共4页
相位展开是光栅投影廓术中的一个关键步骤。对加权最小二乘相位展开算法的原理进行了介绍,利用小波多分辨率特性对Picard迭代算法进行了改进。改进的算法将误差分解为低频和高频成分,对它们分别进行Picard迭代来提高收敛速度。实验结果... 相位展开是光栅投影廓术中的一个关键步骤。对加权最小二乘相位展开算法的原理进行了介绍,利用小波多分辨率特性对Picard迭代算法进行了改进。改进的算法将误差分解为低频和高频成分,对它们分别进行Picard迭代来提高收敛速度。实验结果证明:改进后的算法具有收敛速度快,抗噪能力强等优点。 展开更多
关键词 光栅投影轮廓术 相位展开 加权最小二乘 Picard迭代 小波多分辨率分析
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小波变换在傅立叶变换轮廓术中的应用 被引量:1
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作者 陈源画 陈文静 +2 位作者 郑万国 贺少勃 陈远斌 《激光杂志》 CAS CSCD 北大核心 2005年第1期53-54,共2页
从小波变换本质、原理出发 ,说明它在提取条纹位相方面的应用 ,通过阐述小波变换与傅立叶变换两者之间的内在联系 ,将小波变换应用到傅立叶变换轮廓术中 ,并着重用傅立叶变换的原理对小波提取位相的原理进行详细解释。模拟结果表明 :小... 从小波变换本质、原理出发 ,说明它在提取条纹位相方面的应用 ,通过阐述小波变换与傅立叶变换两者之间的内在联系 ,将小波变换应用到傅立叶变换轮廓术中 ,并着重用傅立叶变换的原理对小波提取位相的原理进行详细解释。模拟结果表明 :小波变换在傅立叶变换轮廓术中的应用是正确的、可行的。 展开更多
关键词 小波变换 傅立叶变换 傅立叶变换轮廓术 条纹位相
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低信噪比信号的连续与离散小波变换比较研究 被引量:3
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作者 袁建虎 何竹青 +1 位作者 龙云飞 黄石红 《自动化仪表》 CAS 北大核心 2009年第8期8-10,共3页
详细介绍了离散小波变换与连续小波变换的发展历程及其基本原理,并对强背景噪声干扰下的碰摩信号分别采用这两种方法所达到的效果进行了研究和比较。发现在采用离散正交小波多分辨分析过程中,各层分解信号的非稳态特征几乎被噪声淹没,... 详细介绍了离散小波变换与连续小波变换的发展历程及其基本原理,并对强背景噪声干扰下的碰摩信号分别采用这两种方法所达到的效果进行了研究和比较。发现在采用离散正交小波多分辨分析过程中,各层分解信号的非稳态特征几乎被噪声淹没,以致无法进行有效分析;而连续小波变换具有比离散小波变换更加细致的尺度空间,它在强噪声背景的干扰下,依然可以得到比较满意的分析效果。 展开更多
关键词 小波变换 傅里叶变换 离散 连续 碰摩信号 分辨率分析 相变
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煤矿复杂环境视频拼接技术 被引量:6
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作者 厉丹 钱建生 +1 位作者 刘增宝 杨澎 《煤炭学报》 EI CAS CSCD 北大核心 2011年第5期878-884,共7页
针对煤矿井下噪声大、光照不均等复杂环境传统拼接算法并不适用的问题,提出新的拼接算法。算法采用拼接帧抽取方式提取部分关键帧进行视频拼接,根据相位相关冲激函数能量高效检测重叠区域并对乱序帧排序,将统计分析中样本主成分分析引入... 针对煤矿井下噪声大、光照不均等复杂环境传统拼接算法并不适用的问题,提出新的拼接算法。算法采用拼接帧抽取方式提取部分关键帧进行视频拼接,根据相位相关冲激函数能量高效检测重叠区域并对乱序帧排序,将统计分析中样本主成分分析引入SIFT特征向量降维中,用互不相关的新样本信息来描述原样本信息,降低了特征向量生成时间,通过结合多频带提升小波,定义融合规则并选择合适的融合策略,实现平滑拼接。实验表明,此算法提高了匹配效率,无需人工排序,解决了复杂环境容易误匹配、接缝明显等现象,拼接效果平滑自然,适合煤矿环境。 展开更多
关键词 煤矿 拼接 主成分分析 相位相关 提升小波
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