Title :
Fundamental study of measurement of cardiorespiratory signals in a sitting position using piezoelectric sensors
Author :
Igasaki, Tomohiko ; Yoshikawa, Kenichi ; Murayama, N.
Author_Institution :
Dept. of Inf. Technol. on Human & Environ. Sci., Kumamoto Univ., Kumamoto, Japan
Abstract :
In this paper, we propose a measurement system to extract the heartbeat and respiration signals from piezoelectric sensors located in a chair seat. Eight healthy male subjects (22-26 years old) sat on a chair with piezoelectric sensors. The experiment consisted of five acquisitions (300 s recording with 30 s resting). In the 1st acquisition, the subject was instructed to maintain a relax state. During the next three acquisitions, the subject maintained respiration rates of 3, 4, and 5 s. The order was randomly given for each subject. Finally, the subject was instructed to stay in a resting state for 300 s. Band-pass filters were used to separate the heartbeat and respiration signals from the output signal of the piezoelectric sensors (heartbeat: 0.7-7 Hz, respiration: 0.1-0.4 Hz). Then, the standard heartbeat interval was calculated using the autocorrelation function to generate a template. Heartbeat and respiration signals were extracted using a two-dimensional cross-correlation pattern matching method. For validation, the error ratio between the piezoelectric sensor data and the reference data was determined. The error ratios of the heartbeat interval and respiration interval were 2.89±4.41% and 5.57±4.42%, respectively. Therefore, it is suggested that heartbeat and respiration signals extracted from piezoelectric sensors in a sitting position can be used as an alternative method for extracting biological signals.
Keywords :
band-pass filters; cardiology; correlation methods; feature extraction; medical signal processing; patient diagnosis; pattern matching; piezoelectric transducers; pneumodynamics; source separation; autocorrelation function; band-pass filter; biological signal extraction; cardiorespiratory signal; error ratio; frequency 0.1 Hz to 0.4 Hz; frequency 0.7 Hz to 7.0 Hz; heartbeat signal extraction; heartbeat signal separation; measurement system; output signal; piezoelectric sensor data; reference data; relax state; respiration interval; respiration rate; respiration signal extraction; respiration signal separation; sitting position; standard heartbeat interval; time 3 s; time 30 s; time 300 s; time 4 s; time 5 s; two-dimensional cross-correlation pattern matching method; Electrocardiography; Heart beat; Heart rate variability; Monitoring; Position measurement; Sensors; Standards;
Conference_Titel :
Engineering in Medicine and Biology Society (EMBC), 2013 35th Annual International Conference of the IEEE
Conference_Location :
Osaka
DOI :
10.1109/EMBC.2013.6610382