Figure 2

Respiratory rate estimation, from top to bottom: nasal thermistor (taken as the gold-standard), EDR_RS (amplitude modulation-based method), and EDR_RSA (respiratory sinus arrhythmia-based method). The right panels are the estimated respiratory rates. The left panels are the respiratory waveforms corresponding to the shaded area on the right (note that the original recording was 300 s long. Only the respiratory waveforms corresponding to the shaded area on the right is presented on the left to enhance clarity). Each estimate (closed-circle marks on the right) corresponds to a 20 s long window with 15 s overlaps between consecutive windows (thus estimates are updated every 5 s). For this example, within the shaded area the RSA method provided a better respiratory estimate than the RS method.