IEEE Trans Biomed Circuits Syst. 2011 Aug;5(4):330-8. doi: 10.1109/TBCAS.2011.2161304.
This paper presents effective signal-processing techniques for the compensation of motion artifacts and ambient light offsets in a reflective photoplethysmography sensor suitable for wearable applications. A ratiometric comparison of infrared (IR) and red absorption characteristics cancels out noise that is multiplicative in nature and amplitude modulation of pulsatile absorption signals enables rejection of additive noise. A low-power, discrete-time pulse-oximeter platform is used to capture IR and red photoplethysmograms so that the data used for analysis have noise levels representative of what a true body sensor network device would experience. The proposed artifact rejection algorithm is designed for real-time implementation with a low-power microcontroller while being robust enough to compensate for varying levels in ambient light as well as reducing the effects of motion-induced artifacts. The performance of the system is illustrated by its ability to extract a typical plethysmogram heart-rate waveform since the sensor is subjected to a range of physical disturbances.
本文提出了一种有效的信号处理技术，用于补偿适合可穿戴应用的反射式光体积描记传感器中的运动伪影和环境光偏移。通过对红外 (IR) 和红光吸收特性进行比率比较，可以消除本质上是乘法的噪声，并且对脉动吸收信号进行幅度调制可以抑制加法噪声。低功耗、离散时间脉搏血氧计平台用于捕获 IR 和红光光体积描记图，以便用于分析的数据具有与真实身体传感器网络设备所经历的噪声水平相当的噪声水平。所提出的伪影消除算法旨在通过低功耗微控制器进行实时实现，同时足够稳健，可以补偿环境光的不同水平，并减少运动引起的伪影的影响。通过传感器受到一系列物理干扰的情况下提取典型的体积描记图心率波形的能力来说明系统的性能。
