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Multiple description scalable video coding based on 3D lifted wavelet transform 被引量:3
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作者 KIM Yong-deak 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第5期857-863,共7页
In this work, a new method to deal with the unconnected pixels in motion compensated temporal filtering (MCTF) is presented, which is designed to improve the performance of 3D lifted wavelet coding. Furthermore, multi... In this work, a new method to deal with the unconnected pixels in motion compensated temporal filtering (MCTF) is presented, which is designed to improve the performance of 3D lifted wavelet coding. Furthermore, multiple description scalable coding (MDSC) is investigated, and novel MDSC schemes based on 3D wavelet coding are proposed, using the lifting imple- mentation of temporal filtering. The proposed MDSC schemes can avoid the mismatch problem in multiple description video coding, and have high scalability and robustness of video transmission. Experimental results showed that the proposed schemes are feasible and adequately effective. 展开更多
关键词 Multiple description SCALABLE coding (MDSC) MOTION compensated temporal filtering (MCTF) Block-split bidi-rectional MOTION estimation 3D lifted wavelet transform
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小波分频自注意力Transformer图像去雨网络 被引量:2
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作者 方思严 刘斌 《计算机工程与应用》 CSCD 北大核心 2024年第6期259-273,共15页
针对视觉Transformer对高频信息捕捉能力弱以及目前许多图像去雨方法易丢失细节的问题,提出小波分频自注意力Transformer图像去雨网络(WFDST-Net)。小波分频自注意力Transformer(WFDST)作为WFDST-Net的主要模块,其利用不可分提升小波变... 针对视觉Transformer对高频信息捕捉能力弱以及目前许多图像去雨方法易丢失细节的问题,提出小波分频自注意力Transformer图像去雨网络(WFDST-Net)。小波分频自注意力Transformer(WFDST)作为WFDST-Net的主要模块,其利用不可分提升小波变换获取特征图的低频分量和高频分量,分别在低频和高频中进行自注意力交互,使模块从低频中学习恢复全局结构的能力,在高频中强化捕捉雨纹等线条细节的能力,增强对不同频域特征的建模能力。WFDST-Net采用U形架构并通过不可分提升小波变换获取多尺度特征,可在捕获不同形状高频雨纹的同时保证信息的完整性。相比其他图像去雨相关的Transformer,WFDST-Net具有更低的参数量。此外,提出VOCRain250数据集用于联合图像去雨和语义分割任务,该数据集比目前广泛使用的BDD150更具优势。实验表明,所提方法增强了视觉Transformer对不同频域信息的捕获能力,并在合成和真实数据集以及VOCRain250中的表现优于目前先进的去雨方法,能有效去除复杂雨纹并保留更多细节特征。 展开更多
关键词 图像去雨 transformER 自注意力 不可分提升小波 频域
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Vegetation field spectrum denoising via lifting wavelet transform
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作者 周广柱 杨锋杰 王翠珍 《Journal of Coal Science & Engineering(China)》 2008年第1期131-135,共5页
Field spectrum pretreatment experiments were carried out, and denoising numerical experiment via lifting wavelet transform (LWT) was designed, and several famous test signals including blocks, bumps, heavy sine and ... Field spectrum pretreatment experiments were carried out, and denoising numerical experiment via lifting wavelet transform (LWT) was designed, and several famous test signals including blocks, bumps, heavy sine and doppler were processed via Lw'r in these experiment. And the field spectrum was processed via Lw'r. Experiments proved that SNRG-tO-SNRN curves have similar feature and they all have a peak. And SNRG of almost all employed wavelets have higher value with SNRN between 0 and 20 dB. When signal is at high SNR, the SNRG is very little, and the MSED of denoised signal became little by little. LWT is more suite to denoise the low SNR or heavy noise contaminated signals. Bior4.4 have wider SNRN interval for denoising comparing with other five wavelets, includ- ing haar, db6, sym6, bior2.2 and bior3.3. Original field spectrum is processed by 3 stage liftings based on bior4.4 to denoise the trivial noise-contaminated regions. On processing the water band signal, logarithm transform is firstly taken. And then the spectrum is denoised via LWT based on bior4.4. The results show that an excellent denoised spectrum can be get, especially between 350 nm and 1 800 nm, and between 1 960 nm to 2 500 nm. While there is still a bump around 1 900 nm, this maybe due to the spectrum machine's limited precision. 展开更多
关键词 vegetation field spectrum lifting wavelet transform DENOISE numerical ex-periment
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Seismic data compression based on integer wavelet transform 被引量:1
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作者 WANG Xi-zhen(王喜珍) TENG Yun-tian(滕云田) +1 位作者 GAO Meng-tan(高孟潭) JIANG Hui(姜慧) 《Acta Seismologica Sinica(English Edition)》 CSCD 2004年第z1期123-128,共6页
Due to the particularity of the seismic data, they must be treated by lossless compression algorithm in some cases. In the paper, based on the integer wavelet transform, the lossless compression algorithm is studied.... Due to the particularity of the seismic data, they must be treated by lossless compression algorithm in some cases. In the paper, based on the integer wavelet transform, the lossless compression algorithm is studied. Comparing with the traditional algorithm, it can better improve the compression rate. CDF (2, n) biorthogonal wavelet family can lead to better compression ratio than other CDF family, SWE and CRF, which is owe to its capability in can- celing data redundancies and focusing data characteristics. CDF (2, n) family is suitable as the wavelet function of the lossless compression seismic data. 展开更多
关键词 lossless compression integer wavelet transform lifting scheme biorthogonal wavelet
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AN EFFICIENT 3-DIMENSIONAL DISCRETE WAVELET TRANSFORM ARCHITECTURE FOR VIDEO PROCESSING APPLICATION 被引量:1
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作者 Ganapathi Hegde Pukhraj Vaya 《Journal of Electronics(China)》 2012年第6期534-540,共7页
This paper presents an optimized 3-D Discrete Wavelet Transform (3-DDWT) architecture. 1-DDWT employed for the design of 3-DDWT architecture uses reduced lifting scheme approach. Further the architecture is optimized ... This paper presents an optimized 3-D Discrete Wavelet Transform (3-DDWT) architecture. 1-DDWT employed for the design of 3-DDWT architecture uses reduced lifting scheme approach. Further the architecture is optimized by applying block enabling technique, scaling, and rounding of the filter coefficients. The proposed architecture uses biorthogonal (9/7) wavelet filter. The architecture is modeled using Verilog HDL, simulated using ModelSim, synthesized using Xilinx ISE and finally implemented on Virtex-5 FPGA. The proposed 3-DDWT architecture has slice register utilization of 5%, operating frequency of 396 MHz and a power consumption of 0.45 W. 展开更多
关键词 3-D Discrete wavelet transform (3-DDWT) lifting scheme PIPELINING Video coding Low power
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Low complexity reconfigurable architecture for the 5/3 and 9/7 discrete wavelet transform
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作者 Xiong Cheng yi Tian Jinwen Liu Jian 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2006年第2期303-308,共6页
Efficient reconfigurable VLSI architecture for 1-D 5/3 and 9/7 wavelet transforms adopted in JPEG2000 proposal, based on lifting scheme is proposed. The embedded decimation technique based on fold and time multiplexin... Efficient reconfigurable VLSI architecture for 1-D 5/3 and 9/7 wavelet transforms adopted in JPEG2000 proposal, based on lifting scheme is proposed. The embedded decimation technique based on fold and time multiplexing, as well as embedded boundary data extension technique, is adopted to optimize the design of the architecture. These reduce significantly the required numbers of the multipliers, adders and registers, as well as the amount of accessing external memory, and lead to decrease efficiently the hardware cost and power consumption of the design. The architecture is designed to generate an output per clock cycle, and the detailed component and the approximation of the input signal are available alternately. Experimental simulation and comparison results are presented, which demonstrate that the proposed architecture has lower hardware complexity, thus it is adapted for embedded applications. The presented architecture is simple, regular and scalable, and well suited for VLSI implementation. 展开更多
关键词 VLSI discrete wavelet transform lifting scheme embedded decimation reeonfigurable.
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An Approach to Integer Wavelet Transform for Medical Image Compression in PACS
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作者 YANG Yan ZHANG Dong 《Wuhan University Journal of Natural Sciences》 CAS 2000年第2期204-206,共3页
We study an approach to integer wavelet transform for lossless compression of medical image in medical picture archiving and communication system (PACS). By lifting scheme a reversible integer wavelet transform is gen... We study an approach to integer wavelet transform for lossless compression of medical image in medical picture archiving and communication system (PACS). By lifting scheme a reversible integer wavelet transform is generated, which has the similar features with the corresponding biorthogonal wavelet transform. Experimental results of the method based on integer wavelet transform are given to show better performance and great applicable potentiality in medical image compression. 展开更多
关键词 Key words integer wavelet transform lifting scheme lossless compression PACS
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基于多通道的彩色图像多重水印算法
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作者 郑秋梅 赵丹 +1 位作者 牛薇薇 林超 《计算机工程》 CAS CSCD 北大核心 2024年第9期246-254,共9页
针对多重水印技术如何确定最优的嵌入区域,以实现多个水印之间的权衡问题,提出一种基于多通道嵌入的彩色图像多重水印算法。当嵌入水印时,选择在彩色图像R、G、B 3个通道嵌入不同的水印图像,目的是嵌入更多的水印信息。通过提升小波变换... 针对多重水印技术如何确定最优的嵌入区域,以实现多个水印之间的权衡问题,提出一种基于多通道嵌入的彩色图像多重水印算法。当嵌入水印时,选择在彩色图像R、G、B 3个通道嵌入不同的水印图像,目的是嵌入更多的水印信息。通过提升小波变换(LWT)和非下采样剪切波变换(NSST)提取宿主图像每个通道中的方向性特征,确定水印的嵌入位置,以提高对常规攻击和几何攻击的鲁棒性。通过将加密的水印有效信息嵌入到具有良好稳定性的奇异值矩阵中,保证水印的提取效果。实验结果表明,嵌入水印后的图像峰值信噪比(PSNR)在43 dB以上,所提算法具备良好的不可见性,对嵌入水印后的图像进行高强度的旋转、滤波、剪切等攻击,提取水印的归一化系数(NC)值在0.95以上,其中,滤波攻击对应的NC值可以达到0.99以上,水印信息提取完整、清晰可辨,表现出较强的鲁棒性。同时,该算法可以1次嵌入3个水印图像,具有更高的嵌入容量。因此,与现有的多重水印算法相比,该算法的不可见性、鲁棒性和嵌入容量均有较大的提升。 展开更多
关键词 多重水印 提升小波变换 非下采样剪切波变换 鲁棒性 嵌入容量
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基于LWT的可见光OFDM-IM系统研究
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作者 王宁 赵黎 +1 位作者 张峰 孟祥艳 《激光杂志》 CAS 北大核心 2024年第1期148-153,共6页
针对索引调制正交频分复用(OFDM-IM)技术峰均比过高,对相位噪声和载波频偏敏感,系统复杂度高等问题,提出基于小波提升变换(LWT)的可见光OFDM-IM系统。首先选择正交小波基作为子载波,通过对信号的分裂、预测和更新,将信号分为高频信号和... 针对索引调制正交频分复用(OFDM-IM)技术峰均比过高,对相位噪声和载波频偏敏感,系统复杂度高等问题,提出基于小波提升变换(LWT)的可见光OFDM-IM系统。首先选择正交小波基作为子载波,通过对信号的分裂、预测和更新,将信号分为高频信号和低频信号,再结合可见光信道构成LWT-OFDM-IM系统,最后通过理论分析和蒙特卡罗方法对系统的可靠性、峰均比特性和最佳小波分解层数进行了仿真验证,结果表明:当子载波N=256,子块中子载波数量L=4,激活子载波数量k=2,系统误码率为10~(-4)时,LWT-OFDM-IM比FFT-OFDM-IM改善约8 dB,相较于DWT-OFDM-IM提高约4 dB。当系统互补累计分布函数(CCDF)为10^(-1)数量级时,LWT-OFDM-IM的峰均比较FFT-OFDM-IM改善约2.3 dB。随着小波层数的递增,系统的误码性能越好,当小波层数为3层时,大约在10 dB附近,误码率可到10^(-5)量级。 展开更多
关键词 可见光通信 正交频分复用 提升小波变换 索引调制 峰均比
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面向多浓度非均匀云雾的双域遥感图像去雾算法
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作者 刘春黔 林浩然 雷印杰 《现代计算机》 2024年第3期9-17,共9页
光学遥感卫星图像容易受到多浓度非均匀云雾的干扰,造成图像质量严重退化。现有的去雾算法难以有效处理多浓度非均匀云雾,于是提出了一种自注意力强化机制,即在自注意力变换中引入一种简单的无参注意力(SimAM)增强自注意力变换的建模能... 光学遥感卫星图像容易受到多浓度非均匀云雾的干扰,造成图像质量严重退化。现有的去雾算法难以有效处理多浓度非均匀云雾,于是提出了一种自注意力强化机制,即在自注意力变换中引入一种简单的无参注意力(SimAM)增强自注意力变换的建模能力,提高对非均匀云雾的感知;为进一步提高网络的纹理细节表征能力,设计了新颖的差分卷积细节增强块,利用差分卷积算子引入梯度级信息,提高去雾网络对纹理细节的恢复能力;为实现RGB域和自适应小波域联合去雾,引入深度自适应提升小波变换实现自适应小波空间,从而实现双域协同去雾。实验结果表明,提出的方法在主流的遥感图像去雾数据集上相较于骨干模型,获得了0.52 dB的PSNR总增益。 展开更多
关键词 遥感图像去雾 自注意力强化 差分卷积 深度自适应提升小波
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A Novel Digital Audio Watermarking Scheme in the Wavelet Domain 被引量:2
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作者 WANGXiang-yang YANGHong-ying ZHAOHong 《Wuhan University Journal of Natural Sciences》 CAS 2005年第1期311-314,共4页
We present a novel quantization-based digital audio walermarking scheme inwavelet domain. By quantizing a host audio's wavelet coefficients (Integer Lifting WaveletTransform) and utilizing the characteristics of h... We present a novel quantization-based digital audio walermarking scheme inwavelet domain. By quantizing a host audio's wavelet coefficients (Integer Lifting WaveletTransform) and utilizing the characteristics of human auditory system (HAS), the grayimage isembedded using our watermarking method. Experimental results show that the proposed watermarkingscheme is inaudible and robust against various signal processing such as noising adding, lossycompression, low pass filtering, re-sampling, and re-quantifying. 展开更多
关键词 digital audio watermarking lifting wavelet transform human auditory system chaotic sequence QUANTIZATION
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New Edge-Directed Interpolation Based-Lifting DWT and MSPIHT Algorithm for Image Compression 被引量:1
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作者 M. Varathaguru R. S. Sabeenian 《Circuits and Systems》 2016年第9期2242-2252,共12页
The amount of image data generated in multimedia applications is ever increasing. The image compression plays vital role in multimedia applications. The ultimate aim of image compression is to reduce storage space wit... The amount of image data generated in multimedia applications is ever increasing. The image compression plays vital role in multimedia applications. The ultimate aim of image compression is to reduce storage space without degrading image quality. Compression is required whenever the data handled is huge they may be required to sent or transmitted and also stored. The New Edge Directed Interpolation (NEDI)-based lifting Discrete Wavelet Transfrom (DWT) scheme with modified Set Partitioning In Hierarchical Trees (MSPIHT) algorithm is proposed in this paper. The NEDI algorithm gives good visual quality image particularly at edges. The main objective of this paper is to be preserving the edges while performing image compression which is a challenging task. The NEDI with lifting DWT has achieved 99.18% energy level in the low frequency ranges which has 1.07% higher than 5/3 Wavelet decomposition and 0.94% higher than traditional DWT. To implement this NEDI with Lifting DWT along with MSPIHT algorithm which gives higher Peak Signal to Noise Ratio (PSNR) value and minimum Mean Square Error (MSE) and hence better image quality. The experimental results proved that the proposed method gives better PSNR value (39.40 dB for rate 0.9 bpp without arithmetic coding) and minimum MSE value is 7.4. 展开更多
关键词 liftING Discrete wavelet transform (DWT) Image Compression Set Partitioning in Hierarchical Trees (SPIHT) New Edge Directed Interpolation (NEDI)
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Lifting Scheme and Its Application to Edge Detection
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作者 Yang Yan +2 位作者 Qin Qian-qing 《Wuhan University Journal of Natural Sciences》 CAS 2003年第01A期74-76,共3页
Lifting scheme is a useful and very general technique for constructing wavelet decomposition. The paper adapts the lifting into redundant lifting to obtain shift invariant wavelet transform. ... Lifting scheme is a useful and very general technique for constructing wavelet decomposition. The paper adapts the lifting into redundant lifting to obtain shift invariant wavelet transform. In prediction and update stages of the lifting morphological operator is adopted for preserving local maxima of a signal over several scales, which is particularly useful in wavelet\|based signal detec tion. The new transform presented in the paper is applied in multiresoluti on edge detection of medical image and experim ent results are given to show better performance and applicable potentiali ty. 展开更多
关键词 lifting scheme redundant wavelet transform morpholog ical operator edge detection
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An Overview on Wavelet Software Packages
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作者 Fan Qi\|bin 1, Li Hong 2 1. School of Mathematics and Statistics, Wuhan University, Wuhan 430072, China 2. School of Electronic Information, Wuhan University, Wuhan 430072, China 《Wuhan University Journal of Natural Sciences》 CAS 2001年第Z1期593-600,共8页
Wavelet analysis provides very powerful problem\|solving tools for analyzing, encoding, compressing, reconstructing, and modeling signals and images. The amount of wavelets\|related software has been constantly multip... Wavelet analysis provides very powerful problem\|solving tools for analyzing, encoding, compressing, reconstructing, and modeling signals and images. The amount of wavelets\|related software has been constantly multiplying. Many wavelet analysis tools are widely available. This overview represents a significant survey for many currently available packages. It will be of great benefit to engineers and researchers for using the toolkits and developing new software. The beginner to learning wavelets can also get a great help from the review. If you browse around at some of the Internet sites listed in the reference of this paper, you may find more plentiful wavelet resources. 展开更多
关键词 wavelet transforms image compression matching pursuit liftING MATLAB
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基于深度置信网络的三相串联故障电弧检测方法
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作者 李斌 舒洋 《电力系统及其自动化学报》 CSCD 北大核心 2023年第7期20-28,共9页
针对三相串联故障电弧的研究大多只是提供一种能够识别出故障电弧的方法,没有考虑用于工业实时检测的可能性,提出了一种基于深度置信网络的故障电弧检测方法。首先,通过搭建三相异步电机故障电弧实验平台获取不同故障情况下的电流数据,... 针对三相串联故障电弧的研究大多只是提供一种能够识别出故障电弧的方法,没有考虑用于工业实时检测的可能性,提出了一种基于深度置信网络的故障电弧检测方法。首先,通过搭建三相异步电机故障电弧实验平台获取不同故障情况下的电流数据,并利用提升小波变换对其进行去噪;其次,通过核主成分分析法KPCA(kernel principal component analysis)提取去噪之后的数据的主成分,减少需要分析的变量;最后,通过PSO优化的DBN网络进行故障识别,与BP神经网络和极限学习机相比,其检测速度更快且准确率达到了98.8%,为应用于实时检测提供了可能性。 展开更多
关键词 故障电弧 故障检测 深度置信网络 提升小波变换 核主成分分析
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基于深度自适应小波网络的通信辐射源个体识别
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作者 刘高辉 于文涛 《网络安全与数据治理》 2023年第5期71-77,共7页
针对现有的通信辐射源个体识别方法中人工提取特征复杂以及深度学习网络的识别机制缺乏清晰解释的问题,提出了一种基于深度自适应小波网络(Deep Adaptive Wavelet Network,DAWN)的通信辐射源个体识别方法。首先分析了选择互调干扰作为... 针对现有的通信辐射源个体识别方法中人工提取特征复杂以及深度学习网络的识别机制缺乏清晰解释的问题,提出了一种基于深度自适应小波网络(Deep Adaptive Wavelet Network,DAWN)的通信辐射源个体识别方法。首先分析了选择互调干扰作为辐射源间个体特征的原因;接着应用了可实现提升小波变换的卷积神经网络结构去提取特征,并在其基础上设计出可以同时完成特征提取和识别的DAWN;最后,选择Oracle数据集验证方法的可行性。实验结果表明:利用DAWN对5个通信辐射源个体识别的准确率为95.5%,并且方法具有良好的抗噪性。 展开更多
关键词 辐射源个体识别 提升小波变换 深度自适应小波网络
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基于蚁群参数优化的LightGBM辐射源个体识别 被引量:5
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作者 顾楚梅 曹建军 +1 位作者 王保卫 徐雨芯 《计算机工程与科学》 CSCD 北大核心 2023年第1期85-94,共10页
为提升辐射源个体识别正确率和运算效率,提出了一种基于蚁群参数优化的LightGBM辐射源个体识别方法。运用提升小波包变换对辐射源信号数据进行特征提取并构建特征参数体系,对得到的特征数据集进行Z-score标准化处理;以最大分类正确率和... 为提升辐射源个体识别正确率和运算效率,提出了一种基于蚁群参数优化的LightGBM辐射源个体识别方法。运用提升小波包变换对辐射源信号数据进行特征提取并构建特征参数体系,对得到的特征数据集进行Z-score标准化处理;以最大分类正确率和最小特征子集规模为目标,建立了LightGBM参数优化和特征选择的数学模型;采用蚁群算法优化LightGBM的6个参数(最小叶子节点数据量、决策树的数量、学习率、L_(1)正则化项的权重、L_(2)正则化项的权重和最小叶子节点样本权重和);根据优化后的LightGBM得到每个特征的重要性值并使用序列后向搜索策略进行特征选择;最后通过LightGBM分类器实现对辐射源信号的分类识别。实验结果表明,所提方法在无噪声、信噪比为10 dB和信噪比为5 dB信号的数据集上的识别正确率优于对比特征选择方法GBDT、XGBoost和LightGBM的,同时特征维数的减少也提升了辐射源个体识别的运算效率。 展开更多
关键词 辐射源个体识别 提升小波包变换 蚁群算法 LightGBM 特征选择
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基于多分类SVM算法的癫痫发作自动检测方法 被引量:1
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作者 王元发 庞宇 +1 位作者 周前能 黄志伟 《重庆邮电大学学报(自然科学版)》 CSCD 北大核心 2023年第3期536-544,共9页
高性能的癫痫脑电信号自动检测方法对减轻医生负担并提高癫痫的诊断效率具有重要临床研究意义。论文提出了一种能够区分正常、癫痫发作和发作间期脑电信号的高性能三分类系统。采用Daubechies 4小波构成的4级提升式小波变换将脑电信号... 高性能的癫痫脑电信号自动检测方法对减轻医生负担并提高癫痫的诊断效率具有重要临床研究意义。论文提出了一种能够区分正常、癫痫发作和发作间期脑电信号的高性能三分类系统。采用Daubechies 4小波构成的4级提升式小波变换将脑电信号分解为不同子带信号,求得不同子带信号的近似熵、Teager能量、局部波动率、自回归系数、Hurst指数特征值;利用Fisher得分法进行特征选择,提高分类精度同时减小计算复杂度;基于二叉树多分类支持矢量机(support vector machine,SVM)对脑电信号分类,实现正常、癫痫发作和发作间期信号的自动检测。实验表明,系统的准确率、灵敏度和特异性均达到100%,优于现有的分类识别方法,提出的三分类系统具有良好的分类性能,为癫痫及癫痫发作的临床检测提供了较好参考价值。 展开更多
关键词 癫痫及癫痫发作检测 三分类器 提升小波变换 二叉树SVM 高性能
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提升小波和Savitzky-Golay滤波结合的近红外光谱去噪研究
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作者 尹欣慧 顾雯雯 《传感技术学报》 CAS CSCD 北大核心 2023年第3期404-410,共7页
在近红外光谱数据处理中,测得的近红外光谱数据不仅有被测样品的近红外特征光谱,还包含一些随机噪声,噪声的存在会影响后续光谱分析的准确性,为提高近红外光谱分析精度,需要对近红外光谱数据进行去噪处理。单一的提升小波去噪、小波去... 在近红外光谱数据处理中,测得的近红外光谱数据不仅有被测样品的近红外特征光谱,还包含一些随机噪声,噪声的存在会影响后续光谱分析的准确性,为提高近红外光谱分析精度,需要对近红外光谱数据进行去噪处理。单一的提升小波去噪、小波去噪以及Savitzky-Golay滤波很难获得较好的去噪效果。因此提出将提升小波变换结合Savitzky-Golay滤波方法用于近红外光谱去噪,对降噪效果进行仿真与评估并与单一去噪方法进行对比。分别对添加随机噪声的1467 nm近红外光谱进行单一小波去噪、提升小波去噪、Savitzky-Golay滤波以及提升小波变换结合Savitzky-Golay滤波进行去噪。实验结果显示所提出的方法去噪后的信噪比比单一三种去噪方法分别提高0.3364、1.1074、0.1287,均方根误差分别降低0.0026、0.0091、0.001,表明所提方法能够有效去除近红外光谱中的噪声信息,并提高去噪的评估指标。 展开更多
关键词 近红外光谱 提升小波变换 Savitzky-Golay滤波 去噪
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基于LWT-OFDM的NOMA-VLC系统
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作者 樊欣 张峰 赵黎 《光通信技术》 2023年第6期6-10,共5页
针对基于傅里叶变换光正交频分复用(FFT-OFDM)的非正交多址可见光通信(NOMA-VLC)系统存在可靠性低、用户公平性差等问题,提出将提升小波变换(LWT)作为载波调制方式,建立基于LWT-OFDM的NOMA-VLC系统,介绍了系统中的信号处理过程,构建了5 ... 针对基于傅里叶变换光正交频分复用(FFT-OFDM)的非正交多址可见光通信(NOMA-VLC)系统存在可靠性低、用户公平性差等问题,提出将提升小波变换(LWT)作为载波调制方式,建立基于LWT-OFDM的NOMA-VLC系统,介绍了系统中的信号处理过程,构建了5 m×5 m×3 m的室内空间实验环境。实验结果表明:与基于FFT-OFDM的NOMA-VLC系统相比,随着正交幅度调制方式的阶次由4增大到64,所提系统的平均误码率达到阀值3.8×10^(-3)时,所需的信噪比(SNR)值较低,至少低4.4 dB;用户性能差异变化不明显甚至不变。 展开更多
关键词 光通信 非正交多址 提升小波变换 可靠性 用户公平性
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