{"id":381,"date":"2019-07-10T17:49:00","date_gmt":"2019-07-10T15:49:00","guid":{"rendered":"http:\/\/benediktehinger.de\/blog\/science\/?p=381"},"modified":"2019-07-12T18:21:51","modified_gmt":"2019-07-12T16:21:51","slug":"new-paper-how-to-compare-and-choose-eye-trackers","status":"publish","type":"post","link":"https:\/\/benediktehinger.de\/blog\/science\/new-paper-how-to-compare-and-choose-eye-trackers\/","title":{"rendered":"New Paper: How to compare and choose eye trackers"},"content":{"rendered":"\n

A (short) laypersons summary<\/h2>\n\n\n\n
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participant performing in the experiment<\/figcaption><\/figure><\/div>\n\n\n\n

TLDR<\/strong>; Using our data\/paper you can find out how well your eye tracker is doing in measuring your<\/em> favourite eye movement<\/p>\n\n\n\n

This newly published paper is open access and I share first co-author ship with the amazing Katharina Gro\u00df! In addition this project was done together with Inga Ibs and Peter K\u00f6nig: A new comprehensive eye-tracking test battery concurrently evaluating the Pupil Labs glasses and the EyeLink 1000<\/a><\/p>\n\n\n\n

We move our eyes about four times per second, which is more often than our heart beats! Many studie show that these eye movements are a window into our minds (e.g. K\u00f6nig et al. 2017) and are commonly used for basic research, marketing research and clinical assesments.<\/p>\n\n\n\n

Even though eyetrackers are so commonly used and so powerful, they are rarely tested for how well they perform besides the manufacturers. Even more critical, no test battery existed before we set out on this project. Together with Katharina Gro\u00df (and Inga Ibs and Peter K\u00f6nig) we developed a new eye tracker test battery which included most of the typically studied eye movements.<\/p>\n\n\n\n

We chose to test two popular eye trackers concurrently: The Eyelink 1000<\/a> and the Pupil Labs<\/a> glasses. The former is the working horse of eye movement research (release 2005), the latter the open hardware\/source innovator (release 2014).<\/p>\n\n\n\n

Our study reveals some strengths and some weakenesses for both eye trackers, but also of our newly proposed test battery. The results are numerours, so I will only depict two tasks:<\/p>\n\n\n\n

Free Viewing<\/h3>\n\n\n\n
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Here you can see where a participant is looking on an image (C & D) with the task to simply explore the image. You can clearly see that the eye trackers agree on the coarse scale (blue & red dots kind of overlay), but not in the specific details (e.g. disagreements that worse\/better at some locations. Also the red (pupil labs) eye-tracker has much higher variability during eye movements . <\/figcaption><\/figure>\n\n\n\n

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Pupil Dilation<\/h3>\n\n\n\n
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Our pupil shrinks when it gets bright and opens up when it gets dark. We tested how well the eye tracker can measure this by presenting differently bright images interleaved by black images (so the pupil can go back (or near) to baseline). We found that on the average, both eye tracker give the same results (both eyetrackers are depicted on top of each other, barely differentiable in figure C) – but calculating the difference between eye trackers for each subject they differ quite a bit (green lines in E are not at 0%)! <\/figcaption><\/figure>\n\n\n\n

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Take home<\/strong><\/h2>\n\n\n\n