2018 Volume 80 Issue 3 Pages 192-199
We examined a method of analyzing an electrocardiogram (ECG)-photoplethysmogram (PPG) simultaneous measurement signal with the aim of developing a diagnosis method of the mind and body condition for visualization of the fatigue state of farm workers. The time delay between ECG and PPG signals was determined with a cross-correlation function. The time delay was found to differ significantly among subjects. In addition, we investigated the possibility of using a Poincaré section as a new method of detecting the nonlinear feature of the PPG. The method of generating the Poincaré section of the PPG using the ECG as a trigger was demonstrated to reduce the scattering of plots when compared with the method of using the average period of the PPG, and the proposed method is considered to be effective in grasping the structure of dynamics.
