Table 1.

Description of features used for classification.

Notation	Name	Description
$F_1$	Mouth outer	Monitor the zygomatic muscle.
$F_2$	Mouth corner	Monitor the zygomatic muscle.
$F_3$	Eye area	Monitor the orbicularis oculi muscle, e.g., blinking.
$F_4$	Eyebrow activity	Monitor the corrugator muscle.
$F_5$	Face area	Monitor facial movement to and away from the camera
$F_6$	Face motion	Describe the total distance the head has moved in any direction in a short period of time.
$F_7$	Facial COM	Describe the overall movement of all 68 facial landmarks.
$F_8$	Remote HR	HR estimated using the rPPG technique proposed by Poh et al. [45].