Table 6: Comparison of different numbers of feature models.

Feature models MAE Runtime(s)

Single-feature
 AAM 4.83 247.2
 LBP 7.56 269.7
 BIF 5.92 245.4

Two-feature
 AAM + BIF 4.74 276.9
 LBP + BIF 5.56 271.7
 AAM + LBP 4.59 272.7

Multifeature (three-feature)
 AAM + LBP + BIF 4.50 320.6