This preview shows page 1. Sign up to view the full content.
Unformatted text preview: n performed • ECG signals
– filtered by detecting the QRS complexes and their position to align the waveforms
Dr. Bülent Yılmaz Bü BME402: Biomedical Signal Processing-II Processing7 Algorithm
• M repetitions -> SNR increase by a factor √M • Obtain a number of realizations • Determine a reference point
– Trigger if external stimulation – Repetitive events • QRS complexes in the ECG or S1 and S2 in the PCG • Extract parts corresponding to events and add them •
to a buffer Divide the results in the buffer by the # of events added
BME402: Biomedical Signal Processing-II Processing- Dr. Bülent Yılmaz Bü 8 4 Example: Visual ERPs Averaging over 10 repetitions Averaging over 20 repetitions Dr. Bülent Yılmaz Bü BME402: Biomedical Signal Processing-II Processing- 9 Example: Noisy ECG signal
• Sample QRS complex • Template matching
– Normalized crosscrosscorrelation – First beat used as a template (86 ms) • Cross-correlation peaks Cross•
(value is 1) at the locations of QRS Choose an appropriate threshold (be careful!) Dr. Bülent Yılmaz Bü BME402: Biomedical Signal Processing-II Processi...
View Full Document
This note was uploaded on 06/11/2012 for the course ENG 411 taught by Professor Cca during the Spring '12 term at Istanbul Universitesi.
- Spring '12