An estimation of heart rate variability from ballistocardiogram measured with bed leg sensors
Ballistocardiogram (BCG) is the repetitive body movements related to cardiac cycle. All night continuous measuring of BCG by using bed sensors enable us to detect sleep stage. However conventional methods are seemed to have unreliability caused by position of lying down. In this paper, we propose a reliable method of all night continuous measuring of BCG. Heart rate variability (HRV) is estimated from BCG measured with new bed sensors by template-matching approach. This approach has three steps, pre-processing, template-creation and template matching. Output of this process were validated with 4 subjects. The mean beat-to-beat interval error was 9.8[ms] and on an average 87.1% of the beat-to-beat intervals were detected.