Utilizing eye movements: Overcoming inaccuracy while tracking the focus of attention during reading

Even though eye movements during reading have been studied intensively for decades, applications that track the reading of longer passages of text in real time are rare. The problems encountered in developing such an application (a reading aid, iDict), and the solutions to the problems are described. Some of the issues are general and concern the broad family of Attention Aware Systems. Others are specific to the modality of interest: eye gaze. One of the most difficult problems when using eye tracking to identify the focus of visual attention is the inaccuracy of the eye trackers used to measure the point of gaze. The inaccuracy inevitably affects the design decisions of any application exploiting the point of gaze for localizing the point of visual attention. The problem is demonstrated with examples from our experiments. The principles of the drift correction algorithms that automatically correct the vertical inaccuracy are presented and the performance of the algorithms is evaluated.