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连续可微阈值函数与尺度阈值的小波去噪 被引量:23
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作者 陈家益 战荫伟 +2 位作者 曹会英 吴兴达 李小飞 《电子测量与仪器学报》 CSCD 北大核心 2018年第10期169-176,共8页
为克服硬阈值、软阈值、半软阈值以及最新提出的阈值函数等小波去噪算法存在的诸多缺陷,提出了连续可微阈值函数与尺度阈值的小波去噪算法。改进阈值函数具有连续性、渐近性和高阶可微性等良好的数学特性,在保持原始有用信号的前提下,... 为克服硬阈值、软阈值、半软阈值以及最新提出的阈值函数等小波去噪算法存在的诸多缺陷,提出了连续可微阈值函数与尺度阈值的小波去噪算法。改进阈值函数具有连续性、渐近性和高阶可微性等良好的数学特性,在保持原始有用信号的前提下,对噪声进行去除。另外,对目前最常用的通用阈值进行改进,根据噪声的强度随分解尺度的增加而减少的规律,在每个小波分解尺度上自适应地设置不同的尺度阈值,保护了幅值较小的原始信号的小波系数。仿真实验的结果显示,相对于现有的小波阈值去噪算法,所提出的算法的信噪比提高1.5 dB以上,均方根误差降低0.015以上。去噪实验的效果图以及实验数据证明,所提出的算法具有更好的去噪性能。 展开更多
关键词 小波变换 小波基 小波阈值去噪 连续可微阈值函数 尺度阈值
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A continuous differentiable wavelet threshold function for speech enhancement 被引量:3
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作者 贾海蓉 张雪英 白静 《Journal of Central South University》 SCIE EI CAS 2013年第8期2219-2225,共7页
Enhanced speech based on the traditional wavelet threshold function had auditory oscillation distortion and the low signal-to-noise ratio (SNR). In order to solve these problems, a new continuous differentiable thresh... Enhanced speech based on the traditional wavelet threshold function had auditory oscillation distortion and the low signal-to-noise ratio (SNR). In order to solve these problems, a new continuous differentiable threshold function for speech enhancement was presented. Firstly, the function adopted narrow threshold areas, preserved the smaller signal speech, and improved the speech quality; secondly, based on the properties of the continuous differentiable and non-fixed deviation, each area function was attained gradually by using the method of mathematical derivation. It ensured that enhanced speech was continuous and smooth; it removed the auditory oscillation distortion; finally, combined with the Bark wavelet packets, it further improved human auditory perception. Experimental results show that the segmental SNR and PESQ (perceptual evaluation of speech quality) of the enhanced speech using this method increase effectively, compared with the existing speech enhancement algorithms based on wavelet threshold. 展开更多
关键词 continuous differentiable wavelet threshold fimction speech enhancement Bark wavelet packet non-fixed deviation noise
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