AGRD	Adaptive green–red difference
ANS	Autonomic nervous system
CHROME	Chrominace-based
GRD	Green–red difference
HR	Heart rate
HRV	Heart rate variability
IBI	Interbeat intervals
ICA	Independent component analysis
iPPG	Image-based photoplethysmography
LE	Laplacian eigenmap
PCA	Principal component analysis
POS	Plane-orthogonal-to-skin
PPG	Photoplethysmography
PR	Pulse rate
PRV	Pulse rate variability
RGB	Red-green-blue
ROI	Region of interest
SPE	Stochastic proximity embedding