Online Gaze Disparity via Binocular Eye Tracking on Stereoscopic Displays

We report on progress in the development of an online system to allow the estimation of eye tracked 3D gaze depth in a stereoscopic environment. The efficacy of our method is demonstrated in two distinctly different configurations: a custom Wheatstone stereoscope, and a commodity active stereo graphics display. We employ a 3D calibration process that determines the parameters of an affine mapping from a depth estimate, based on triangulation using onscreen horizontal disparity, to a refined depth estimate. Triangulation accounts for most of the non-linearity in the transform, and our calibration accounts for individual differences in eye separation and vergence behavior. We demonstrate that, although different binocular eye trackers are used with each display, our approach to online estimation of gaze depth performs similarly on both systems. Importantly, results show that depth estimation error is biased toward the display screen, underestimating target distance from the screen both behind and in front of the screen.