Zhou Congcong, Feng Jingjie, Hu Jun, Ye Xuesong
College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China.
Shanghai Megahealth Technologies Co., LTD, Shanghai, China.
J Med Syst. 2016 Mar;40(3):56. doi: 10.1007/s10916-015-0412-2. Epub 2015 Dec 8.
Pulse rate is one of the major physiological parameters for monitoring of cardiovascular conditions or excise states during daily life. However it is difficult to precisely measure the exact pulse rates as photoplethysmography (PPG) is easy to be affected by motion artifacts. Instead of using accelerometers followed by algorithms such as least mean square (LMS), recursive least square (RLS) and independent component analysis (ICA) or other equipment such as complex laser systems to measure displacement directly, a novel motion artifact estimation method which had lower computational complexity and higher signal dynamic range was studied and implemented, where a differential channel following green and red light PPG channels was applied to reduce the motion artifact caused by displacement of light emitting diode (LED), photo diode (PD) and tissue deformation before the analog signal was converted to digital form. A miniaturized, battery powered wrist worn artifact-resistive pulse rates monitoring system (PRMS) was presented to verify the proposed method. Four kinds of motions were performed and the results showed that the differential channel improved the morphology of the PPG signal and appeared to be artifact resistive during motions through light intensity control and high gain-phase consistency circuit design here.
脉搏率是日常生活中监测心血管状况或运动状态的主要生理参数之一。然而，由于光电容积脉搏波描记法（PPG）容易受到运动伪影的影响，精确测量准确的脉搏率很困难。研究并实现了一种计算复杂度较低且信号动态范围较高的新型运动伪影估计方法，该方法不是使用加速度计及最小均方（LMS）、递归最小二乘（RLS）和独立成分分析（ICA）等算法，也不是使用复杂激光系统等其他设备直接测量位移，而是在模拟信号转换为数字形式之前，通过在绿色和红色光PPG通道之后设置一个差分通道，来减少由发光二极管（LED）、光电二极管（PD）的位移和组织变形引起的运动伪影。提出了一种小型化、电池供电的抗运动伪影手腕佩戴式脉搏率监测系统（PRMS）来验证所提出的方法。进行了四种运动，结果表明，通过这里的光强度控制和高增益相位一致性电路设计，差分通道改善了PPG信号的形态，并且在运动过程中似乎具有抗伪影能力。
