Differences in the Infrared Bright Pupil Response of Human Eyes

In this paper, we describe experiments conducted to explain observed differences in the bright pupil Response of human eyes. Many people observe the bright pupil response as the red-eye effect when taking flash photography. However, there is significant variation on the magnitude of the bright pupil response across the population. Since many commercial gaze-tracking systems use the infrared bright pupil response for eye detection, a clear understanding of the magnitude and cause of the bright pupil variation gives critical insight into the robustness of gaze tracking systems. This paper documents studies we have done to measure the bright pupil differences using infrared light and hypothesis factors that lead to these differences.