基于可穿戴光电传感技术的去运动伪影脉率检测方法

A pulse rate detection method for eliminating motion artifacts based on wearable photoelectric sensing technology

脉搏波是分析人体心血管系统生理状况的重要检测对象,可穿戴光电设备采集的脉搏信号常因人体运动而引入运动伪影,进而影响脉率检测结果的准确性,由于伪影的主要频率分量和光电信号频率相重叠,所以减少伪影有难度。针对现有脉率检测精度不高、抗运动干扰能力不足问题,提出一种结合非线性自适应滤波和线性调频Z变换(CZT)的脉率检测方法。首先对光电容积脉搏波描记法(PPG)采集的信号预处理滤除高频干扰和基线漂移,然后选用微机电系统(MEMS)检测加速度信号作为参考信号,构建基于最小均方(LMS)的非线性自适应滤波器去除运动伪影,最后利用线性调频Z变换(CZT)对信号进行频谱分析计算脉率值。实验通过对10名受试者采集的实验数据进行性能评估,结果表明,该方法能有效从干扰脉搏波信号中恢复出原始信号,测得的受试者脉率平均绝对误差为1.96 bpm,具有较高的准确率和抗干扰能力。

Pulse wave is an important detection object for analyzing the physiological condition of human cardiovascular system.Pulse signals collected by wearable photoelectric devices often disturbed by motion artifacts due to human movement,which in turn affects the accuracy of detection results,and it is difficult to reduce the artifacts due to the fact that the main frequency components of the artifacts overlap with the frequency of the optoelectronic signals.In this paper,a pulse rate detection method combining nonlinear adaptive filtering and linear frequency-modulated BXZ-transform(CZT)is proposed to solve the problems of low pulse rate detection accuracy of existing pulse rate detection and insufficient resistance to motion interference.Firstly,the signal acquired by photoelectric volumetric pulse wave tracing(PPG)is preprocessed to remove high-frequency interference and baseline drift,and then the micro-electro-mechanical system(MEMS)is chosen as the reference signal to construct a nonlinear adaptive filter based on the least mean square(LMS)to remove the motion artifacts.Finally,the frequency spectrum of the signal is analyzed by CZT to calculate the pulse rate.The experiments are carried out by evaluating the performance of the experimental data collected from 10 subjects,and the results show that the method can effectively recover the original signal from the interference pulse wave signal,and the average absolute error of the measured pulse rate is 1.96 bpm,which is highly accurate and anti-interference ability.