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.

The wearable healthcare system should be not only small and easy for users to wear them but accurate in measuring physiological signals in daily life without any inconvenience. To meet these requirements, we propose the U-healthcare System which consists of a Smart Headband and a Health-state Monitor program. It can monitor the health-state in walking and running. The Smart Headband measures a photo-plethysmography (PPG) signal at the forehead for monitoring the heart rate and acceleration signals. The Health-state Monitor program is developed to show the health-state. Health-state Monitor program is operated in the handheld computer, such like (Ultra Mobile Personal Computer (UMPC). It provides the user PPG, heart rate and steps for the precise measurement, Adaptive Noise Cancellation (ANC) is introduced. The Smart Headband and the Health-state Monitor program are communicated by the WPAN using Zigbee protocol. If the heart rate is higher or lower than usual, the Health-state Monitor program sends the SMS message to the designated person, such as family or the attending physician in the medical center, to inform the emergency situation.