Monitoring Driving in a Monotonous Environment: Classification and Recognition of Driving Fatigue Based on Long Short-Term Memory Network

Table 4

Fatigue index grade.

Fatigue degree	Expressway		Rural road
	PERCLOS	Pupil area	PERCLOS	Pupil area
Awake state	<4.3	>1962.6	<8.61	>1653.6
Mild fatigue	6.1∼9.3	1622.7∼1798.6	11.7∼17.4	1298.9∼1442.6
Moderate fatigue	10.5∼14.1	1464.8∼1568.9	22.5∼30.1	1028.6∼1164.1
Severe fatigue	>17.7	<1369.6	>35.3	<917.3