Fig. 1: Overview of the CHILL recording protocol.
From: The reliability of remote photoplethysmography under low illumination and elevated heart rates
Each session begins with informed consent and equipment setup, followed by a sequence of four one-minute recordings under different lighting and heart rate conditions. Light settings alternate between bright and dim, and heart rate is elevated mid-session using brief physical activity. Time-aligned markers were used for synchronization between video and physiological signals.
