Yes, what I want is that the gaze co-ordinates should be modified to a specified margin according to the head position. I know that the Tobii hardware automatically compensates for head movement but sometimes it has some margin that could be corrected if, for example, the head movements have higher angles and more distantiated from the Tobii Eye Tracker.
What I was thinking was getting the head positions and, based on those co-ordinates, adjust the gaze margin.
The other idea was recalibrate the Tobii Eye Tracker every time the user moves his head to a different fixed position. Then some dots could appear to make a new calibration.
What do you think it would be the best approach?