Table 1: All features used in this study and brief descriptions.

FeatureBrief description

FD 𝑛 1 _ 𝑛 2 Distance between points 𝑛 1 and 𝑛 2 in a frontal (or profile) image
FDH 𝑛 1 _ 𝑛 2 Horizontal distance between 𝑛 1 and 𝑛 2 in an image
FDV 𝑛 1 _ 𝑛 2 Vertical distance between 𝑛 1 and 𝑛 2 in an image
FA 𝑛 1 _ 𝑛 2 _ 𝑛 3 Angle of three points 𝑛 1 , 𝑛 2 , and 𝑛 3 in an image
FA 𝑛 1 _ 𝑛 2 Angle between the line through 2 points 𝑛 1 and 𝑛 2 and a horizontal line
FR02_psuFD(17, 26)/FD(18, 25)
FR03_psu(FD(18, 25) + FD(118, 125))/FDH(33, 133)
FR05_psuFDH(33, 133)/FD(43, 143)
FR06_psuFDH(33, 133)/FDV(52, 50)
FR08_psuFD(43, 143)/FDV(52, 50)
FArea02Area of the contour formed by the points 53, 153, 133, 194, 94, 33, and 53
FArea03Area of the contour formed by the points 94, 194, 143, 43, and 94
Fh_Cur_Max_DistanDistance between points 7 and 77 in a profile image
Fh_Angle_ 𝑛 1 _ 𝑛 2 Angle between the line through 2 points 𝑛 1 and 𝑛 2 and a horizontal line
Nose_Angle_ 𝑛 1 _ 𝑛 2 Angle between the line through 2 points 𝑛 1 and 𝑛 2 and a horizontal line
Nose_Angle_ 𝑛 1 _ 𝑛 2 _ 𝑛 3 Angle of 3 points 𝑛 1 , 𝑛 2 , and 𝑛 3 in a frontal(or profile) image
SAn 1_ 𝑛 2 Angle between the line through 2 points 𝑛 1 and 𝑛 2 and a horizontal line
Fh_Cur_Max_R79_69FD(77, 9)/FD(6, 9)
Nose_Area_ 𝑛 1 _ 𝑛 2 _ 𝑛 3 Area of the triangle formed by 3 points 𝑛 1 , 𝑛 2 , and 𝑛 3 in a profile image
EUL_L_el1 ~ EUL_L_el7Slope of the tangent at a point (el1 el7) in a frontal image
EUL_L_DHFDH(el1, el7)
EUL_L_MAXFDH(el1, 𝑒 𝑙 m a x )
EUL_L_RMAXFDH(el1, 𝑒 𝑙 m a x )/FDH(el1, el7)
EUL_L_SbFDV(el7, el1)/FDH(el7, el1)
EUL_L_StFDV( 𝑒 𝑙 m a x , el7)/FDH( 𝑒 𝑙 m a x , el7)
EUL_L_SfFDV( 𝑒 𝑙 m a x , el1)/FDH( 𝑒 𝑙 m a x , el1)
EUL_L_KhmeanAverage curvature of the left (or right) upper eyelid contour
EUL_L_khmaxMaximum curvature of the left (or right) upper eyelid contour
EUL_R_er1~ EUL_R_er7Slope of the tangent at a point (er1 er7) in a frontal image
EUL_R_DHFDH(er1, er7)
EUL_R_MAXFDH(er1, 𝑒 𝑟 m a x )
EUL_R_RMAXFDH(er1, 𝑒 𝑟 m a x )/FDH(er1, er7)
EUL_R_SbFDV(er7, er1)/FDH(er7, er1)
EUL_R_StFDV( 𝑒 𝑟 m a x , er7)/FDH( 𝑒 𝑟 m a x , er7)
EUL_R_SfFDV( 𝑒 𝑟 m a x , er1)/FDH( 𝑒 𝑟 m a x , er1)
EUL_R_KhmeanAverage curvature of the left (or right) upper eyelid contour
EUL_R_khmaxMaximum curvature of the left (or right) upper eyelid contour
PDH44_53Horizontal distance between 𝑛 1 and 𝑛 2 in a frontal (or profile) image