摘要
针对硬阈值函数不连续导致间断点和软阈值函数过渡光滑导致偏差过大的不足,提出一种新型阈值函数,通过调节其参数,该阈值函数可在软硬阈值函数之间变动,从而兼具两者的特性.引入算子对各尺度阈值进行修正以能更好地反映噪声和信号小波系数随尺度的变化规律,选择db5小波作为母小波分解到第四尺度,将基于新阈值函数的小波算法用于bumps、doppler波形以及电能质量扰动信号去噪中,实验结果表明,该方法在有效去噪的同时保留了扰动关键信息,信噪比和均方误差指标均优于软、硬阈值函数去噪法,新方法具有更好的去噪效果.
The discontinuity of hard threshold function leads to breakpoints and transitional smooth of soft threshold function leads to excessive deviation.To solve these problems,a new threshold function is proposed.By adjusting the parameter,the new threshold function can be changed between hard and soft threshold functions,which has both characteristics.In order to better reflect the variation of wavelet coefficients of noise and signal with different scales,an operator is introduced to modify the threshold of each scale.The db5 wavelet is selected as the mother wavelet to decompose the signal to the fourth scale,and the wavelet algorithm based on the new threshold function is applied to the denoising of bumps,doppler waveforms and power quality disturbance signals.The experimental results show that the new method retains the key disturbance information while effectively denoising.The SNR and MSE of the proposed denoising method are better than those of the soft and hard threshold function denoising methods,which shows that the new method has better denoising effect.
作者
龚静
GONG Jing(School of Electrical and Information Engineering,Beijing University of Civil Engineering and Architecture,Beijing Key Laboratory of Intelligent Processing for Building Big Data,Beijing 100044)
出处
《北京建筑大学学报》
2020年第2期67-73,共7页
Journal of Beijing University of Civil Engineering and Architecture
基金
国家公派留学基金资助(201809960015)。
关键词
阈值函数
小波去噪
电能质量
阈值
奇异性检测
threshold function
wavelet denoising
power quality
threshold
singularity detection
