基于小波分析的光电脉搏波奇异性处理

Processing of singularity in the Photoelectric Pulse Wave by Wavelet Analysis

高精度的光电脉搏波信号,对于动态光谱法血液成分无创检测非常重要。要获得高精度的脉搏波信号,首先就要对信号中的噪声奇异点进行定位和修正。本文选择Marr小波,针对信号中的单个脉冲噪声和窄带脉冲噪声。研究了基于小波分析的光电脉搏波奇异性处理。利用脉搏波信号极大值线的周期性,在每个周期段内,首先利用单个脉冲噪声与有用信号截然不同的李氏指数特性,对单个脉冲噪声进行了处理。然后利用窄带脉冲的小波系数极大值线的特点对常规小波方法难以处理的窄带脉冲噪声进行分析定位。鉴于模极大值重构算法比较复杂,本文利用线性插值法对被定位的噪声奇异点进行了修正。仿真实验表明,利用小波分析和线性插值相结合的方法可以完成对光电脉搏波信号的奇异性处理,提高了脉搏波信号的幅值检测精度。

Photoelectric pulse wave with high signal-noise ratio （SNR） is very important for the noninvasive detection of the blood compositions by dynamic spectroscopy. In order to acquire signal with high SNR, singularity detection and correction must be applied. In this paper, with the Marr wavelet selected, applying of the wavelet analysis on the singularity analysis of the pulse wave, including the impulse and narrowband interference, is studied. Due to the periodicity of the modulus maxima line of the pulse wave, at each periodic time, by use of the different lipsehitz exponent characters of the signal and impulse noise, the noise is processed, then the characters of the modulus maxima line of the narrowband interferences is used to locate the narrowband interferences, which is difficult for the wavelet analysis to deal with. Because of the complexity of the modulus maxima restructuring algorithm, the singularity located is corrected by the linear interpolation. It has been proved by the experiment using the wavelet analysis combining with the linear interpolation, the singularity in the pulse wave can be successfully located and corrected, and the precision of the pulse wave signal is improved.