Nonintrusive measurement of biological signals for ubiquitous healthcare

In order to monitor biological signals during our daily lives for ubiquitous healthcare, nonintrusive biological signal monitoring methods have been developed. Without contacting sensors and connecting wires to the subjects, the biological signals are monitored using specially designed methods. ECG is measured using capacitive coupling over clothes and PPG is measured nonintrusively during ordinary activities. Blood pressure is also estimated from ECG and PPG by calculating pulse arrival time (PAT). These methods can be applied to evaluate the health levels of subjects without intervening in their ordinary daily activities.