Sheet-type Device for Unconstrained Heart Sound Measurement and White Noise Reduction by Wiener Filter

Cardiac information is crucial in the diagnosis of cardiac diseases. Phonocardiography is widely used to obtain cardiac information at a medical institution. In this paper, we propose a sheet-type sensing device for unconstrained measurement of heart sound and filtering for heart sound extraction. We conducted a validation experiment with two males in their twenties and a female in her fifties. The experimental results show that the proposed system measured the first and second heart sound regardless of respiratory condition, thickness of bedding, and sleeping posture. Further validations are needed to establish that the proposed system is able to measure abnormal heart sounds which indicate the presence of cardiac diseases.