抄録
Plethysmographic signals were detected remotely (0.5 m) under the standard room light by the use of a built-in webcam on note PC. The RGB color movies were recorded at video-rate and the region of interest was set to the forehead of each subject. Changes in the average intensity of G channel appeared to be consistent with pulsation, respiration and the body movement. When the time series data was subjected to Fourier analysis, we found the characteristic peaks corresponding to the frequency of heart rate and respiration in the spectra. As for the B channel, we observed the respiration signal but the very weak signal of pulsation. Neither were almost contained in the R channel. In subjects that kept running for 3 minutes, the exercise increased the frequency of the plethysmographic signal measured remotely, suggesting the sympathetic nerve activation. This was confirmed by the increase in the LF/HF ratio of electrocardiogram and the salivary amylase activity. Furthermore, the exercise increased pulsation as well as respiration measured remotely. The remote vital monitor would be one of the evaluation methods of sympathetic nerve activity and be especially useful for the person who has difficulty wearing the sensor for sympathetic nerve activity.
