Remote Photoplethysmography-Triggered Signal Averaging for Non-Contact Heart Sound Measurement.

Remote photoplethysmography- (rPPG-) triggered signal averaging, a novel approach for the non-contact heart sound measurement, was proposed. Recently, there has been a growing need for a heart sound monitoring method for the early detection of cardiovascular diseases. Therefore, we proposed a non-contact heart sound measurement approach using a signal averaging with rPPG peaks as triggers. This approach can emphasize the heart sound, the only sound synchronized in time with the heartbeat, and reduces other ambient noises. Herein, we evaluated the feasibility of our approach. As a result, it was indicated that our approach can measure the heart sound without contact using the appropriate triggers. The accuracy required for the triggers was approximately 0.04 s as the standard deviation of the R-R interval estimation error.