改进的希尔伯特-黄变换在基于PPG信号血压测量中的应用

PPG Signal-Based Blood Pressure Estimation Using Modified Hilbert-Huang Transform

提出了一种基于光电容积脉搏波(PPG)信号的血压测量系统,包括信号采集硬件设置和基于Hilber-Huang变换(HHT)的PPG信号处理方法。在设置中,使用手机(MP)作为上位控制器,在其控制下,手指夹探头产生的PPG信号被采集,放大,滤波后存储在SD卡中并传送到MP。此外,基于MATLAB软件,提出了一种改进的HHT算法。通过与小波阈值法(WT)比较,从信噪比,特征提取和血压(BP)计算的角度评估了该方法的有效性。实验结果表明,虽然两级Rigrsure小波阈值去噪方法在PPG信号去噪方面表现最好,但处理后的数据的特征信息也与实际值存在较大差异。相比之下,所提出的改进HHT算法去噪效果表现略差,但成功地保留了单个周期信号的基本特征。综上所述,本文提出了一种基于MP的PPG便携式设备和改进的HHT信号处理方法,并将其应用于BP估计,未来将在老年人日常健康检查,病人康复等方面发挥应有的作用。

A blood pressure measurement system based on photoplethysmography (PPG) signal is proposed including a hardware setup for signal collecting and a modified Hilber-Huang Transform (HHT) based PPG signal processing method. In the setup, mobile phone (MP) is used as the upper con-troller, under its control, PPG signal generated by a finger clip probe is collected, amplified, filtered, stored in SD card and transferred to MP. Furthermore, based on the MATLAB software, a modified HHT algorithm is proposed. Comparisons with wavelet threshold method are performed to evaluate the effectiveness of the proposed method from the views of ratio of signal to noise, feature extraction and blood pressure (BP) calculation. The experimental results indicate though the two-level Rigrsure wavelet threshold denoising method has the best performance in PPG signal denoising, the characteristic information of the processed data is also in great difference with the actual value. In contrast, the proposed modified HHT algorithm makes a little deviation, and retains the basic characteristics of the single periodic signal successfully. In conclusion, a MP based PPG portable setup and a modified HHT signal processing method are proposed and applied for BP estimation, their promising future will be in daily health inspection for the elderly, rehabilitation of patients, etc.