Hi,
I recently conducted an experiment using an eye-tracking device (tobii) and its extension for E-prime to verify the impact of visual distractions on a mathematical task; I previously built a virtual classroom environment in which during the presentation of some equations on a blackboard, distractions appeared in some other areas of the screen. I recorded participant's eye movements to detect whether the distractions were actually effective. E-prime generated .gaze files that i open in excel for interpretation.
Now, in my files I have the X,Y coordinates of the eye gazes of each participant recorded every 2/300 milliseconds.
My problem is that I would like to compare the coordinates from my .gaze files with the coordinates of the objects appearing on the screen to determine whether the gaze actually fell in the area of the distraction or not, and therefore determine if the recorded eye movements could be significant data to answer my research questions. I know this would have been easy by defining AOIs previous to the experiment but unfortunately i did not.
So, does anyone know how to transform the coordinates from the gaze files into coordinates on the screen so that i can determine whether participants were actually looking at the distractions?
Thank you in advance for you time.
Regards,
Sebastiano
Dear Sebastiano,
Since you are using a Tobii eye tracker, you may open your experiment in TobiiStudio. There, you can obtain the coordinates in which each distractor appears in the visual display by selecting the objects with your mouse.
It may be the case that TobiiStudio provides you with the coordinates based on the resolution in which your videos were generated (e.g., 1024*780). It does not need to be necessarily the resolution that E-prime and/or your experimental screen are using (e.g., 1920*1080). If the coordinates obtained from TobiiStudio for your distractors and the raw gaze-data from E-prime do not match in resolution, you need to transform the coordinate matrix in order to have the same 0,0 (X,Y) at the top left corner of the screen. I hope that answers your question. Let me know if I can be of any help.
All the best,
Miren
Miren Arantzeta
Dear Miren,
Thank you for your answer, it was indeed helpful!
I did managed to calculate the coordinates with an online program but i will also try out the method you suggested.
Bests,
Sebastiano
How can I match x y coordinates from a Pupil Labs eye tracker into coordinates of the video?
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