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Direction of Arrivals Estimation for Correlated Broadband Radio Signals by MVDR Algorithm Using Wavelet 认领 引用 被引量：4
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作者 Ying Liu Chi Xie Yourun Zhang 《China Communications》 SCIE CSCD 2017年第3期190-197,共8页
A theoretical relationship between the wavelet transform and the fast fourier transformation(FFT) methods in broadband wireless signal is proposed for solving the direction of arrivals(DOAs) estimation problem. This l... A theoretical relationship between the wavelet transform and the fast fourier transformation(FFT) methods in broadband wireless signal is proposed for solving the direction of arrivals(DOAs) estimation problem. This leads naturally to the derivation of minimum variance distortionless response(MVDR) algorithm, which combines the benefits of subspace methods with those of wavelet, and spatially smoothed versions are utilized which exhibits good performance against correlated signals. We test the method's performance by simulating and comparing the performance of proposed algorithm, FFT MVDR and MVDR with correlated signals, and an improved performance is obtained. 展开更多
关键词 array antenna broadband radio signal direction of arrival MVDR algorithm wavelet
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Optimal reorientation of underactuated spacecraft using genetic algorithm with wavelet approximation 认领 引用 被引量：5
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作者 Xinsheng Ge Liqun Chen 《Acta Mechanica Sinica》 SCIE EI CAS 2009年第4期547-553,共7页
The optimal attitude control of an underactuated spacecraft is investigated in this paper. The flywheels of the spacecraft can somehow only provide control inputs in two independent directions. The dynamic equations a... The optimal attitude control of an underactuated spacecraft is investigated in this paper. The flywheels of the spacecraft can somehow only provide control inputs in two independent directions. The dynamic equations are formulated for the spacecraft under a nonholonomic constraint resulting from the constant time-rate of the total angular momentum of the system. The reorientation of such underactuated spacecraft is transformed into an optimal control problem. A genetic algorithm is proposed to derive the control laws of the two flywheels angle velocity inputs. The control laws are approximated by the discrete orthogonal wavelets. The numerical simulations indicate that the genetic algorithm with the wavelet approximation is an effective approach to deal with the optimal reorientation of underactuated spacecraft. 展开更多
关键词 Underactuated spacecraft Reorientation Attitude control Genetic algorithm Wavelet
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RESEARCH OF PROBLEMS ON REALIZING DIRECT ALGORITHM OF WAVELET TRANSFORM 认领 引用 被引量：2
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作者 Tang BaopingZhong YoumingQin ShurenDepartment of Mechanical Engineering,Chongqing University,Chongqing 400044, China 《Chinese Journal of Mechanical Engineering》 EI CAS 2003年第2期136-140,共5页
Direct algorithm of wavelet transform (WT) is the numerical algorithmobtained from the integral formula of WT by directly digitization. Some problems on realizing thealgorithm are studied. Some conclusions on the dire... Direct algorithm of wavelet transform (WT) is the numerical algorithmobtained from the integral formula of WT by directly digitization. Some problems on realizing thealgorithm are studied. Some conclusions on the direct algorithm of discrete wavelet transform (DWT),such as discrete convolution operation formula of wavelet coefficients and wavelet components,sampling principle and technology to wavelets, deciding method for scale range of wavelets, measuresto solve edge effect problem, etc, are obtained. The realization of direct algorithm of continuouswavelet transform (CWT) is also studied. The computing cost of direct algorithm and Mallat algorithmof DWT are still studied, and the computing formulae are obtained. These works are beneficial todeeply understand WT and Mallat algorithm. Examples in the end show that direct algorithm can alsobe applied widely. 展开更多
关键词 wavelet transform direct algorithm mallat algorithm
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Biomedical Image Processing Using FCM Algorithm Based on the Wavelet Transform 认领 引用 被引量：2
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作者 闫玉华 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2004年第3期18-20,共3页
An effective processing method for biomedical images and the Fuzzy C-mean (FCM) algorithm based on the wavelet transform are investigated.By using hierarchical wavelet decomposition, an original image could be decompo... An effective processing method for biomedical images and the Fuzzy C-mean (FCM) algorithm based on the wavelet transform are investigated.By using hierarchical wavelet decomposition, an original image could be decomposed into one lower image and several detail images. The segmentation started at the lowest resolution with the FCM clustering algorithm and the texture feature extracted from various sub-bands. With the improvement of the FCM algorithm, FCM alternation frequency was decreased and the accuracy of segmentation was advanced. 展开更多
关键词 biomedical image processing FCM algorithm wavelet transform texture feature
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The Algorithm of Balanced Orthogonal Multiwavelets and Its Application in Denoising 认领 引用
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作者 QIU Ai-zhong 《International Journal of Plant Engineering and Management》 2011年第4期221-224,共4页
In order to extract fault features of a weak signal from the strong noise and maintain signal smoothness, a new method of denoising based on the algorithm of balanced orthogonal multiwavelets is proposed. Multiwavelet... In order to extract fault features of a weak signal from the strong noise and maintain signal smoothness, a new method of denoising based on the algorithm of balanced orthogonal multiwavelets is proposed. Multiwavelets have several scaling functions and wavelet functions, and possess excellent properties that a scalar wavelet cannot satisfy simultaneously, and match the different characteristics of signals. Moreover, the balanced orthogonal multiwavelets can avoid the Gibbs phenomena and their processes have the advantages in denoising. Therefore, the denoising based on the algorithm of balanced orthogonal multiwavelets is introduced into the signal process. The algorithm of bal- anced orthogonal multiwavelet and the implementation steps of this denoising are described. The experimental compar- ison of the denoising effect between this algorithm and the traditional multiwavelet algorithm was done. The experi- ments indieate that this method is effective and feasible to extract the fault feature submerged in heavy noise. 展开更多
关键词 balanced orthogonal multiwavelets wavelet algorithm signal denoising extracting signal features fault diagnosis
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An Orthogonal Wavelet Transform Fractionally Spaced Blind Equalization Algorithm Based on the Optimization of Genetic Algorithm 认领 引用
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作者 廖娟 郭业才 季童莹 《Defence Technology（防务技术）》 CAS 2011年第2期65-71,共7页
An orthogonal wavelet transform fractionally spaced blind equalization algorithm based on the optimization of genetic algorithm(WTFSE-GA) is proposed in viewof the lowconvergence rate,large steady-state mean square er... An orthogonal wavelet transform fractionally spaced blind equalization algorithm based on the optimization of genetic algorithm(WTFSE-GA) is proposed in viewof the lowconvergence rate,large steady-state mean square error and local convergence of traditional constant modulus blind equalization algorithm(CMA).The proposed algorithm can reduce the signal autocorrelation through the orthogonal wavelet transform of input signal of fractionally spaced blind equalizer,and decrease the possibility of CMA local convergence by using the global random search characteristics of genetic algorithm to optimize the equalizer weight vector.The proposed algorithm has the faster convergence rate and smaller mean square error compared with FSE and WT-FSE.The efficiency of the proposed algorithm is proved by computer simulation of underwater acoustic channels. 展开更多
关键词 information processing technique genetic algorithm orthogonal wavelet transform fractionally spaced equalizer blind equalization underwater acoustic channel
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Optimization of a crude distillation unit using a combination of wavelet neural network and line-up competition algorithm 认领 引用 被引量：3
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作者 Bin Shi Xu Yang Liexiang Yan 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2017年第8期1013-1021,共9页
The modeling and optimization of an industrial-scale crude distillation unit （CDU） are addressed. The main spec- ifications and base conditions of CDU are taken from a crude oil refinery in Wuhan, China. For modelin... The modeling and optimization of an industrial-scale crude distillation unit （CDU） are addressed. The main spec- ifications and base conditions of CDU are taken from a crude oil refinery in Wuhan, China. For modeling of a com- plicated CDU, an improved wavelet neural network （WNN） is presented to model the complicated CDU, in which novel parametric updating laws are developed to precisely capture the characteristics of CDU. To address CDU in an economically optimal manner, an economic optimization algorithm under prescribed constraints is presented. By using a combination of WNN-based optimization model and line-up competition algorithm （LCA）, the supe- rior performance of the proposed approach is verified. Compared with the base operating condition, it is validat- ed that the increments of products including kerosene and diesel are up to 20% at least by increasing less than 5% duties of intermediate coolers such as second pump-around （PA2） and third Dump-around （PA3）. 展开更多
关键词 Crude oil distillation Wavelet neural network Line-up competition algorithm Optimization
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Detection of Rice Bacterial Leaf Blight Using Hyperspectral Technology and Continuous Wavelet Analysis 认领 引用
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作者 Kaihao Shi Lin Yuan +5 位作者 Qimeng Yu Zhongting Shen Yingtan Yu Chenwei Nie Xingjian Zhou Jingcheng Zhang 《Phyton-International Journal of Experimental Botany》 SCIE 2025年第7期2033-2054,共22页
Plant diseases are a major threat that can severely impact the production of agriculture and forestry.This can lead to the disruption of ecosystem functions and health.With its ability to capture continuous narrow-ban... Plant diseases are a major threat that can severely impact the production of agriculture and forestry.This can lead to the disruption of ecosystem functions and health.With its ability to capture continuous narrow-band spectra,hyperspectral technology has become a crucial tool to monitor crop diseases using remote sensing.However,existing continuous wavelet analysis(CWA)methods suffer from feature redundancy issues,while the continuous wavelet projection algorithm(CWPA),an optimization approach for feature selection,has not been fully validated to monitor plant diseases.This study utilized rice bacterial leaf blight(BLB)as an example by evaluating the performance of four wavelet basis functions-Gaussian2,Mexican hat,Meyer,andMorlet-within theCWAandCWPAframeworks.Additionally,the classification models were constructed using the k-nearest neighbors(KNN),randomforest(RF),and Naïve Bayes(NB)algorithms.The results showed the following:(1)Compared to traditional CWA,CWPA significantly reduced the number of required features.Under the CWPA framework,almost all the model combinations achieved maximum classification accuracy with only one feature.In contrast,the CWA framework required three to seven features.(2)Thechoice of wavelet basis functions markedly affected the performance of themodel.Of the four functions tested,the Meyer wavelet demonstrated the best overall performance in both the CWPA and CWA frameworks.(3)Under theCWPAframework,theMeyer-KNNandMeyer-NBcombinations achieved the highest overall accuracy of 93.75%using just one feature.In contrast,under the CWA framework,the CWA-RF combination achieved comparable accuracy(93.75%)but required six features.This study verified the technical advantages of CWPA for monitoring crop diseases,identified an optimal wavelet basis function selection scheme,and provided reliable technical support to precisely monitor BLB in rice(Oryza sativa).Moreover,the proposed methodological framework offers a scalable approach for the early diagnosis and assessment of plant stress,which can contribute to improved accuracy and timeliness when plant stress is monitored. 展开更多
关键词 Hyperspectral continuous wavelet analysis continuous wavelet projection algorithm wavelet basis function disease monitoring
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Conformal Wavelet Finite-difference Time-domain Algorithm for Analysis of Milimeter Wave Attenuation on Coplanar Waveguide 认领 引用
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作者 DAI Hong-quan CHEN Hai-yan 《Semiconductor Photonics and Technology》 2007年第3期206-209,共4页
Addressed is the calculation of millimeter wave attenuation on coplanar waveguide(CPW). A novel conformal wavelet finite-difference time-domain(CWFDTD) algorithm is proposed with emphasis on its application in calcula... Addressed is the calculation of millimeter wave attenuation on coplanar waveguide(CPW). A novel conformal wavelet finite-difference time-domain(CWFDTD) algorithm is proposed with emphasis on its application in calculation of millimeter wave attenuation on CPW, which is the combination of conformal algorithm dealing with the deformed cell with Wavelet-FDTD using multi-resolution analysis(MRA). Derived is the difference formulation for multi-resolution time domain(MRTD) based on Daubechies wavelets, and also given is the stability conditions for wavelet-FDTD algorithm. To validate its accuracy and efficiency, this novel method is applied to calculate the millimeter wave attenuation on lithium niobate CPW. Numerical results demonstrate that this new CWFDTD algorithm has the same accuracy with the conformal finite-difference time-domain(CFDTD) and conformal finite-difference time-domain based on alternating-direction implicit method(ADI-CFDTD), but saves computational time and computer memory. 展开更多
关键词 millimeter wave attenuation conformal wavelet FDTD algorithm multi-resolution analysis multi-resolution time domain coplanar waveguide
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智能采掘设备振动信号降噪方法研究 认领 引用 被引量：1
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作者 秦朝中 甘涛 +4 位作者 彭博 李勇 孙传猛 赵云飞 梁勇 《矿业安全与环保》 CAS 北大核心 2026年第1期205-214,共10页
准确采集各种信号及提取特征是实现采掘装备自动控制的关键。电动机轴承的振动信号是采掘装备自动识别煤岩的重要信号之一,其在复杂工况条件下受到环境噪声及部件摩擦的严重干扰,易导致信号特征模糊,影响采掘设备信号特征提取。提出一... 准确采集各种信号及提取特征是实现采掘装备自动控制的关键。电动机轴承的振动信号是采掘装备自动识别煤岩的重要信号之一,其在复杂工况条件下受到环境噪声及部件摩擦的严重干扰,易导致信号特征模糊,影响采掘设备信号特征提取。提出一种基于改进型自适应噪声完备集合经验模态分解(ICEEMDAN)与遗传算法优化多尺度排列熵(MPE)的联合小波降噪方法,并通过信噪比、均方误差和降噪误差比来评价其有效性。研究表明:相较于EEMD-MPE、CEEMDAN-MPE与ICEEMDAN-MPE等传统方法,联合小波降噪方法在仿真信号和机械设备轴承振动数据集中的信噪比最大、均方误差最小、降噪误差比最大,该方法不仅展现出优异的噪声抑制能力,同时有效保留了表征机械状态的特征信息。通过研究煤矿采掘设备的电动机轴承信号,可为研究整个采掘设备的信号特征提供前置研究,并为后续煤岩自动识别与工矿设备自动化、智能化奠定了一定的基础。 展开更多
关键词 采掘设备 振动信号 信号降噪 ICEEMDAN 多尺度排列熵 遗传算法 小波阈值
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基于开源降水数据和Wavelet算法张家口市降水量时空变化研究 认领 引用
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作者 马丁 《水利科技与经济》 2025年第9期103-107,共5页
基于开源降水量栅格数据和Wavelet算法,对张家口市1961-2020年降水量时空变化特征进行研究。结果表明,近60年来张家口市降水量存在弱增加趋势(P>0.05),年均变化斜率0.30mm/a;空间上降水量变化趋势呈不均衡分布,除在尚义与张北县结合... 基于开源降水量栅格数据和Wavelet算法,对张家口市1961-2020年降水量时空变化特征进行研究。结果表明,近60年来张家口市降水量存在弱增加趋势(P>0.05),年均变化斜率0.30mm/a;空间上降水量变化趋势呈不均衡分布,除在尚义与张北县结合部、涿鹿县东侧等局部呈减少趋势外(-1.4~0mm/a),大部分地区为增加趋势(0~1.12mm/a);降水量变化主周期为3~6a,其中在市域东南侧与西北侧的变化周期为3~4a,其他地区为4~6a。研究结果明确了张家口降水量变化特征及其空间分布格局,对认识气候变化响应具有一定启示意义。 展开更多
关键词 降水量 开源栅格数据 Wavelet算法 空间分布
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小波域语音降噪多算法对比研究 认领 引用 被引量：2
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作者 田玉静 张民 左红伟 《青岛理工大学学报》 CAS 2026年第1期105-114,共10页
深入研究了低信噪比输入下小波包语音增强技术,提出了一种改进的小波包自适应阈值降噪算法。通过与小波软阈值降噪方法的分析与比较,仿真实验验证了该算法在语音增强领域的有效性。为了获得更好的听觉感受,进一步探讨了多小波包自适应... 深入研究了低信噪比输入下小波包语音增强技术,提出了一种改进的小波包自适应阈值降噪算法。通过与小波软阈值降噪方法的分析与比较,仿真实验验证了该算法在语音增强领域的有效性。为了获得更好的听觉感受,进一步探讨了多小波包自适应阈值算法降噪技术及多小波包分析结合维纳滤波语音降噪技术。设计了4种算法的语音降噪处理仿真实验,对比研究了4种算法的语音降噪处理效果。通过对多小波包的精细分解和维纳滤波的优化处理,多小波包维纳滤波在提高输出信号质量、去除噪声干扰方面展现出了卓越的性能。该研究不仅在理论上具有重要意义,在实际应用中也有着广泛的前景。 展开更多
关键词 语音降噪 小波包 多小波包 自适应阈值算法 维纳滤波
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基于RIME-VMD联合小波阈值的爆破振动信号去噪方法 认领 引用 被引量：3
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作者 王薇 程忠耀 +1 位作者 向延念 宋良俊 《铁道科学与工程学报》 EI CAS CSCD 北大核心 2026年第1期465-479,共15页
随着现代化建设的加速推进,邻近既有建筑的爆破作业日益增多,监测和分析爆破引起的振动对结构安全的评估至关重要。然而,爆破振动信号的非线性特性和复杂的环境因素干扰使得从实测信号中提取有效信号成分难度较大,给后续的信号分析造成... 随着现代化建设的加速推进,邻近既有建筑的爆破作业日益增多,监测和分析爆破引起的振动对结构安全的评估至关重要。然而,爆破振动信号的非线性特性和复杂的环境因素干扰使得从实测信号中提取有效信号成分难度较大,给后续的信号分析造成了较大影响。为提高爆破振动信号的降噪精度,将雾凇优化算法(RIME)、变分模态分解(VMD)和小波阈值进行融合,形成一种爆破振动信号联合去噪方法。该方法首先通过雾凇优化算法对VMD关键参数进行优化,然后通过优化后的VMD对振动信号进行自适应分解,剔除方差贡献率较低的分量,再采用小波阈值对筛选后的分量进行降噪处理,最终重构得到去噪后的信号。对该方法的降噪效果进行仿真分析和实际工程验证,结果表明:在仿真信号分析中,经RIME-VMD联合小波阈值的降噪方法去噪后的信号与无噪声的纯净信号相比,形状与特征高度吻合,且信噪比(SNR)和均方根误差(RMSE)等去噪指标优于EMD、小波阈值、EMD联合小波阈值等常用去噪方法;经工程实际案例验证,该方法能够在极大保留原信号基本特征的前提下,有效去除爆破振动信号中的高频噪声,降噪后信号更加符合爆破振动信号的主频范围,且具有比EMD、小波阈值、EMD联合小波阈值等常用去噪方法更好的去噪效果。该研究成果对爆破振动信号的降噪处理具有参考意义。 展开更多
关键词 爆破振动 信号处理 联合降噪 雾凇优化算法 变分模态分解 小波阈值去噪
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用于无线无源SAW传感器的高精度频率估计算法设计 认领 引用
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作者 杨景刚 郭东亮 +4 位作者 邹颖 孙磊 孙铭辰 薛蓄峰 王文 《压电与声光》 CAS 北大核心 2026年第4期650-655,共6页
针对无线无源声表面波(SAW)传感器回波信号持续时间短,信噪比低,频率估计精度差等问题,本文创新性地提出并实现了一种结合小波阈值去噪的高精度Rife频率估计算法。通过建立完整处理链有效滤除混频噪声,同时在较短采样长度下提高频率估... 针对无线无源声表面波(SAW)传感器回波信号持续时间短,信噪比低,频率估计精度差等问题,本文创新性地提出并实现了一种结合小波阈值去噪的高精度Rife频率估计算法。通过建立完整处理链有效滤除混频噪声,同时在较短采样长度下提高频率估计精度,降低频率估计误差。基于搭建的SAW无线无源传感系统开展实验,结果表明,本文提出的算法抑制环境噪声幅度可达50%,频率估计精度相比于同等点数的FFT提高了10倍,为提高无线无源SAW传感系统的检测精度提供了有效方案。 展开更多
关键词 声表面波 小波阈值去噪 Rife算法 频率估计
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结合先验知识的退化条码复原算法研究 认领 引用
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作者 袁斌 王道芳 李晨 《机械设计与制造》 北大核心 2026年第3期110-114,119,共5页
针对商品分拣装置入库过程中条码识别效果不佳的问题,提出了一种结合先验知识的条码复原算法。通过快速小波变换算法对透视映射后的校正图像进行预增强,并设计了一种自适应阈值的条码重构方法,首先通过垂直投影曲线的波峰波谷对边界初... 针对商品分拣装置入库过程中条码识别效果不佳的问题,提出了一种结合先验知识的条码复原算法。通过快速小波变换算法对透视映射后的校正图像进行预增强,并设计了一种自适应阈值的条码重构方法,首先通过垂直投影曲线的波峰波谷对边界初步确定,然后通过局部阈值和差分运算构建的隶属度函数对边界精确定位;最后以公开条码数据集和实际采集图像进行试验验证。结果表明,所提方法能够有效解决退化条码的解码问题,在识别率提升了7%以上,更易对外界因素造成的模糊条码进行复原。 展开更多
关键词 条码 复原算法 小波变换 隶属度函数 自适应局部阈值 差分运算
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基于IEA-DWT预处理的弱光环境图像特征匹配研究 认领 引用
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作者 郑冬 冯鹏 +3 位作者 谭周楠 唐曾 伍成金 杜炜 《强激光与粒子束》 CAS CSCD 北大核心 2026年第9期183-192,共10页
弱光环境直接导致图像亮度不足、细节湮没且噪声显著,使传统特征匹配算法性能骤降,误匹配率激增。基于此,提出了一种融合光照增强算法(IEA)与离散小波变换(DWT)的新型预处理算法,旨在通过多阶段图像优化为后续特征匹配提供高质量输入。... 弱光环境直接导致图像亮度不足、细节湮没且噪声显著,使传统特征匹配算法性能骤降,误匹配率激增。基于此,提出了一种融合光照增强算法(IEA)与离散小波变换(DWT)的新型预处理算法,旨在通过多阶段图像优化为后续特征匹配提供高质量输入。该算法运用IEA自适应提升图像整体亮度与局部对比度,再通过DWT多尺度分解,对分离的低频分量进行主体结构保留,对不同方向的高频分量进行阈值处理,进而实现边缘增强与降噪,最终将优化图像输入SURF算法完成特征提取与匹配。为了验证该算法的有效性,开展了极弱光、微弱光、弱光环境下的图像特征匹配。实验结果表明,相较于单一IEA或DWT预处理方法,所提算法效果最为显著,平均正确特征匹配对达到261,提高6.53倍。新型预处理算法IEA-DWT可以有效解决弱光环境下图像特征匹配中细节模糊和噪声干扰的核心问题,为弱光场景下的特征匹配提供了可靠的技术支撑。 展开更多
关键词 弱光环境 光照增强算法 离散小波变换 预处理
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油葵联合收获机清选损失监测装置设计与试验 认领 引用
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作者 郭辉 韩骏轩 +3 位作者 吕增帅 仇世龙 董远德 郭烈红 《吉林大学学报（工学版）》 EI CAS CSCD 北大核心 2026年第4期1135-1146,共12页
针对现有联合收获机损失监测技术不适用于采集处理油葵籽粒损失信号的问题,设计了一种适用于油葵联合收获机的清选损失监测装置。该装置主要由聚偏二氟乙烯(PVDF)压电薄膜、信号采集处理电路板以及安装调节装置构成,可实现对油葵清选损... 针对现有联合收获机损失监测技术不适用于采集处理油葵籽粒损失信号的问题,设计了一种适用于油葵联合收获机的清选损失监测装置。该装置主要由聚偏二氟乙烯(PVDF)压电薄膜、信号采集处理电路板以及安装调节装置构成,可实现对油葵清选损失速率的实时监测。运用Multisim软件对滤波器性能进行仿真分析,结果表明,该滤波器在非阻带增益平坦且增益为1,对50 Hz干扰信号的衰减效果显著,能够保证采集信号的准确性和完整性;设计了基于STM32系列单片机的小波变换自适应滤波(DWT-LMS)算法,通过Matlab软件将其与传统最小均方(LMS)算法进行仿真对比,结果表明,DWT-LMS算法对信号中噪声的抑制效果更优;通过台架试验确定了油葵籽粒和清选杂余(碎叶柄、碎葵盘以及碎叶片)对应的阈值范围,并验证了监测装置在不同时长下的可靠性,结果表明,该清选损失监测装置的最大监测误差为9.09%,平均监测误差约为7.59%,平均损失速率约为0.63 g/s,可为油葵联合收获机清选系统优化提供理论依据。 展开更多
关键词 农业机械 油葵联合收获机 损失监测 压电薄膜 小波变换自适应滤波算法
双光梳飞秒激光雷达数据的VMD–SFOA去噪方法 认领 引用
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作者 周国清 秦国富 +2 位作者 周祥 宋有建 朱嘉俊 《红外与激光工程》 EI CAS CSCD 北大核心 2026年第5期289-299,共11页
针对双光梳飞秒激光雷达在复杂噪声条件下测距精度和稳定性受限的问题,提出一种基于变分模态分解(Variational Mode Decomposition,VMD)和海星优化算法(Starfish Optimization Algorithm,SFOA)的自适应小波阈值去噪方法。首先利用VMD对... 针对双光梳飞秒激光雷达在复杂噪声条件下测距精度和稳定性受限的问题,提出一种基于变分模态分解(Variational Mode Decomposition,VMD)和海星优化算法(Starfish Optimization Algorithm,SFOA)的自适应小波阈值去噪方法。首先利用VMD对回波分解,引入峭度和信息熵指标筛选有效模态,在小波域构造具有可调形状参数的自适应阈值函数,并由SFOA对分解参数和阈值参数统一寻优。在含复合噪声的仿真实验与合作、非合作目标实验中,将文中方法与VMD、经验模态分解(EMD)、小波变换(WT)以及高斯滤波传统去噪方法进行了对比,并通过室外测距实验验证了测距系统的稳定性。结果证明:在三个实验中相比于传统去噪方法信噪比(Signal-to-noise ratio,SNR)分别提升了7.09、1.17、1.05 dB,均方根误差(Root mean square error,RMSE)分别降低了0.04、0.11×10−2、0.21×10−2,艾伦偏差曲线更低。这表明文中方法能够在噪声抑制与波形保真之间取得平衡,提升双光梳飞秒激光雷达测距性能,为复杂场景下的工程应用提供一种可行的信号处理方案。 展开更多
关键词 双光梳飞秒激光雷达 变分模态分解 自适应小波阈值 海星优化算法
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基于小波包变换与CNN算法的高速铁路路基挡墙结构损伤智能识别方法 认领 引用
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作者 杨昊天 李永强 +1 位作者 王璐 孙高升 《铁道建筑》 北大核心 2026年第7期152-159,共8页
针对高速铁路路基挡墙结构在长期服役中受荷载-环境耦合作用产生的损伤难以及时识别的问题,本文提出一种结合小波包变换与卷积神经网络(Convolutional Neural Network,CNN)的智能损伤识别方法。首先,基于室内缩尺模型试验,模拟了不同裂... 针对高速铁路路基挡墙结构在长期服役中受荷载-环境耦合作用产生的损伤难以及时识别的问题,本文提出一种结合小波包变换与卷积神经网络(Convolutional Neural Network,CNN)的智能损伤识别方法。首先,基于室内缩尺模型试验,模拟了不同裂缝位置、裂缝宽度及列车动荷载条件下的挡墙运行状态,采集了结构的加速度动力响应信号。其次,利用小波包变换对非平稳振动信号进行多尺度分解,重构并计算各频段能量分布,构建了归一化的小波包能量特征向量。最后,构建了融合多头注意力机制的CNN深度学习模型,自适应挖掘特征向量与结构损伤状态之间复杂的非线性映射关系。研究结果表明:挡墙的动力响应及能量分布与激振频率及轴重密切相关;所提方法能有效克服噪声干扰,测试集总体识别准确率达80.2%,宏平均AUC(Area Under Curve)值为0.937,在不同损伤程度的分类识别上表现出优异的泛化能力,为高铁路基支挡结构的健康监测提供了可靠的技术支撑。 展开更多
关键词 铁路路基 挡墙 试验研究 损伤识别 小波包变换 CNN算法
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A New Image Watermarking Scheme Using Genetic Algorithm and Residual Numbers with Discrete Wavelet Transform 认领 引用
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作者 Peter Awonnatemi Agbedemnab Mohammed Akolgo Moses Apambila Agebure 《Journal of Information Security》 2023年第4期422-436,共15页
Transmission of data over the internet has become a critical issue as a result of the advancement in technology, since it is possible for pirates to steal the intellectual property of content owners. This paper presen... Transmission of data over the internet has become a critical issue as a result of the advancement in technology, since it is possible for pirates to steal the intellectual property of content owners. This paper presents a new digital watermarking scheme that combines some operators of the Genetic Algorithm (GA) and the Residue Number (RN) System (RNS) to perform encryption on an image, which is embedded into a cover image for the purposes of watermarking. Thus, an image watermarking scheme uses an encrypted image. The secret image is embedded in decomposed frames of the cover image achieved by applying a three-level Discrete Wavelet Transform (DWT). This is to ensure that the secret information is not exposed even when there is a successful attack on the cover information. Content creators can prove ownership of the multimedia content by unveiling the secret information in a court of law. The proposed scheme was tested with sample data using MATLAB2022 and the results of the simulation show a great deal of imperceptibility and robustness as compared to similar existing schemes. 展开更多
关键词 Discrete Wavelet Transform (DWT) Digital Watermarking Encryption Genetic Algorithm (GA) Residue Number System (RNS) GARN
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