Application of laser doppler vibrocardiography for human heart auscultation

[摘要] ENGLISH ABSTRACT: This thesis investigates the feasibility of the laser Doppler vibrometer (LDV) foruse in the autonomous auscultation of the human heart. As a non-contact measurementdevice, the LDV could become a very versatile biomedical sensor. LDV,stethoscope, piezoelectric accelerometer (PA) and electrocardiogram (ECG) signalswere simultaneously recorded from 20 volunteers at Tygerberg Hospital. Ofthe 20 volunteers, 17 were confirmed to have cardiovascular disease. 3 patients withnormal heart sounds were recorded for control data.The recorded data was successfully denoised using soft threshold wavelet denoisingand ensemble empirical mode decomposition. The LDV was compared tothe PA in common biomedical applications and found to be equally accurate. Theheart sound cycles for each participant were segmented using a combination of ECGdata and a simplicity curve. Frequency domain features were extracted from eachheart cycle and input into a k-nearest neighbours classifier. It was concluded thatthe LDV can form part of an autonomous, non-contact auscultation system.

[发布机构] Stellenbosch University