Figure 7.

Gaze estimation performance of the primary calibration method. (a) Gaze estimation performance based on training set at different depths.$Z_{\mathrm{c}}$ denotes the depth of the calibration plane. The bold black numbers at the bottom are the angular error in degrees (mean ± standard deviation). (b) The parallax between the single (left) and union eye visual system. As the depth of calibration plane increases, the parallax becomes smaller (e.g., ${\theta }_1>{\theta }_2$, ${\theta }_3>{\theta }_4$ ).