Fig. 1. Appearance and structure of PVDF sensor
Fig. 2. Structure of Sleep Diagnosis Pillow
Fig. 3. Signal of PVDF sensor measured during sleep
Fig. 4. Analysis results through STFT (a) 0~5,000 Hz, (b) 0~200Hz
Fig. 5. Analysis results through Wavelet Transform
Fig. 6. Wavelet analysis of low frequency range
Fig. 7. Breathing signals acquired through 4th Butterworth low-pass filtering (Cut-off Frequency= 0.25 Hz)
Fig. 8. Structure for extracting heart rate signal
Fig. 9. R-peak detection using median filter
Fig. 10. Snoring signal synchronized with breathing signal
Fig. 11. Snoring signal acquired through 4th HPF
Fig. 12. High-frequency noise-canceled snoring signal
Fig. 13. Median filter obtained snoring signal
Fig. 14. Extraction of proposed snoring signal
Fig. 15. Heart rate signal obtained using Median Filter and heart rate signal obtained using MP150 system
Fig. 16. Respiratory and snoring signals (a) not using the median filter (b) using median filter
Fig. 17. Comparison of breathing and noise signals (a) not using the median filter (b) using median filter
Fig. 18. Respiratory and Snoring Signals in Patients with Apnea (a) not using the median filter (b) using median filter
Fig. 19. Comparison of Respiratory Signals and Snoring Signals in Patients with Apnea (105~165 secs) (a) not using the median filter (b) using median filter
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