Thesis (MScEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: This thesis investigates the feasibility of the laser Doppler vibrometer (LDV) for
use in the autonomous auscultation of the human heart. As a non-contact measurement
device, the LDV could become a very versatile biomedical sensor. LDV,
stethoscope, piezoelectric accelerometer (PA) and electrocardiogram (ECG) signals
were simultaneously recorded from 20 volunteers at Tygerberg Hospital. Of
the 20 volunteers, 17 were confirmed to have cardiovascular disease. 3 patients with
normal heart sounds were recorded for control data.
The recorded data was successfully denoised using soft threshold wavelet denoising
and ensemble empirical mode decomposition. The LDV was compared to
the PA in common biomedical applications and found to be equally accurate. The
heart sound cycles for each participant were segmented using a combination of ECG
data and a simplicity curve. Frequency domain features were extracted from each
heart cycle and input into a k-nearest neighbours classifier. It was concluded that
the LDV can form part of an autonomous, non-contact auscultation system. / AFRIKAANSE OPSOMMING: Hierdie tesis ondersoek die haalbaarheid daarvan om die laser Doppler vibrasiemeter
(LDV) vir die outonome beluistering van die menslike hart te gebruik. As
'n kontaklose meettoestel kan die LDV werklik 'n veelsydige biomediese sensor
word. Twintig vrywilligers by die Tygerberg Hospitaal se LDV-, stetoskoop-, piësoelektriese
versnellingsmeter (PV)- en elektrokardiogram (EKG) seine is gelyktydig
opgeneem. Uit die 20 vrywilligers was daar 17 bevestigde gevalle van kardiovaskulêre siektes. Die data van drie pasiënte met normale hartklanke is as kontroledata
opgeneem.
Geraas is suksesvol uit die opgeneemde data verwyder deur 'n kombinasie van
sagtedrempelgolf en saamgestelde empiriese modus ontladingstegnieke. Die LDV
was vergelyk met die PV vir algemene biomediese gebruike en daar was gevind
dat dit vergelykbare akkuraatheid het. Die hartklanksiklusse van elke deelnemer
is gesegmenteer deur EKG data en 'n eenvoudskromme te kombineer. Frekwensiegebiedskenmerke
is uit elke hartsiklus onttrek en in 'n k-naastebuurpunt klassifiseerder ingevoer. Daar is tot die gevolgtrekking gekom dat die LDV deel van 'n
outonome, kontaklose beluisteringstelsel kan uitmaak.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/86649 |
| Date | 04 1900 |
| Creators | Koegelenberg, Suretha |
| Contributors | Scheffer, C., Blanckenberg, M. M., Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | xii, 97 p. : ill. |
| Rights | Stellenbosch University |
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