Correlation Analysis of the Time Difference Between Multi-wavelength PPG

Abstract

This work developed a four-channel photoplethysmogram (PPG) acquisition system to collect the multi-wavelength PPG signals of red, yellow, green and blue light at the fingertip simultaneously. Eight subjects including 4 females took part in the experiment, and the multi-wavelength PPG signals from their fingertip were recorded. Since different PPG signal carries the blood pulsation information in different depth of the tissue, the time differences between multi-wavelengths was examined to investigate their relationships. The result shows the three time difference between yellow PPG and other PPGs (red PPG, green PPG and blue PPG) are highly correlated with each other (|r| > 0.7).