Adaptive Noise Cancellation Using Accelerometers for the PPG Signal from Forehead

Abstract

For the upcoming ubiquitous computing environments in the u-health areas involve the measurement of physiological signals in the daily life. However, the measurement of those signals, such as the photoplethysmorgraphy (PPG), and the electrocardiogram (ECG), requires being still tight during the measurement in order to get the accurate result preventing noises caused by the casual movement. In this paper, we propose a method to obtain the accurate physiological signals in the situation where the little movement is allowed. By measuring PPG and motion signals at the forehead during in motion, we calibrate the distorted PPG signal with the motion signals. We show that the calibrated PPG signal is accurate enough by comparing with the result that is measured at the finger without any movement.

Estimation of heart rate from foot worn photoplethysmography sensors during fast bike exercise

“…The method can be used in many parts of the body, such as the forehead [3] and ear [4], and is very popular in emerging smartwatch devices placed on the wrist. However, the PPG recording modality has two significant limitations: PPG signals are highly corrupted by motion artifacts [5] which historically have restricted its use to no-motion situations; and the {delaram.jarchi,alex.casson}@manchester.ac.uk light source requires a large amount of power (typically approximately 1 mW) limiting the operational life of highly miniaturized wearables with small batteries.…”

“…For example, proposed methods are based on Empirical Mode Decomposition (EMD) [6], Independent Component Analysis (ICA) [7], Kalman filtering [8], adaptive filters [3], [9] and sparse signal reconstruction [10]. These have shown to be to able to extract the average heart rate from a motion contained PPG trace to within (approximately) ±5 beats-per-minute (bpm).…”

Ubiquitous Health Monitoring: Integration of Wearable Sensors, Novel Sensing Techniques, and Body Sensor Networks

“…Different from conventional pulse oximeter probes, these sensor assemblies appear in the form of adhesive patch, finger ring, earring, earphone and headband [39] [40]. As an example, the finger-ring sensor developed by Asada et al measured PPG signals at the base of the finer to extract SpO2 and heart rate information, and wirelessly sent them to a host computer.…”

Implementation of Smart Headband for the Wearable Healthcare

“…We made experiments on measuring the PPG signal at the forehead and concluded PPG can be measured at the forehead with the Biopac system. Also, we tested the correlation between the distorted PPG signal and the acceleration signal, and designed an adaptive filter to reduce motion artifacts [7,8].…”