Eye tracking system model with easy calibration

Calibration is one of the most tedious and often annoying aspects of many eye tracking systems. It normally consists in looking at several marks on a screen in order to collect enough data to modify the parameters of an adjustable model. Unfortunately this step is unavoidable if a competent tracking system is desired. Many efforts have been made to achieve more competent and improved eye tracking systems. Maybe the search for an accurate mathematical model is one of the least researched fields. The lack of a parametric description of the gaze estimation problem makes it difficult to find the most suitable model, and therefore generic expressions in calibration and tracking sessions are employed instead. In other words, a model based on parameters describing the elements involved in the tracking system would provide a stronger basis and robustness. The aim of this work is to build up a mathematical model totally based in realistic variables describing elements taking part in an eye tracking system employing the well known bright pupil technique i.e. user, camera, illumination and screen. The model is said to be defined when the expression relating the point the user is looking at with the extracted features of the image (glint position and center of the pupil) is found. The desired model would have to be simple, realistic, accurate and easy to calibrate.