A Novel Two-Stage Illumination Estimation Framework for Expression Recognition

Table 3

Average estimation error with varying illumination under a series of poses. ±90°, I-2-H, indicates horizontal (H) (V for vertical) changes from −90° to 90° with 2° increments (I).

Pose range	Illumination range	Average error	Standard deviation
±90°, I-10-H	±45°, I-4-H	6.41°/7.32°	6.32°/6.36°
±90°, I-20-H	±45°, I-10-H	9.74°/8.27°	13.53°/7.19°
±45°, I-10-V	±45°, I-10-V	2.03°/9.12°	3.07°/10.40°