Fig. 6.
Infrared AC PPG signals acquired from (a) the ear canal, and (b) the finger of a volunteer and the simultaneously acquired (c) skin and (d) core temperature signal for the entire duration of the study. The Y-axis on the left shows the amplitude of the PPG signals while the Y-axis on the right shows the temperature. The spike in finger PPG signal at 11th min is a movement artefact