We are attempting to use our eye tracker on preterm infants, but their focal distance is only around one foot. Is it possible to adjust the eye tracker to function with a subject that close?
Also, how can we make the infant calibration images larger while still using the ones offered?
Thank you.
Now this is a very interesting research area. How preterm are they. 1 Foot is pretty close. Maybe try messing with the settings. If it is not possible that way maybe Tobii can help you guys. Calibration image size should be adjustable by using different version of image. you might need to take the built in image you use and resize it in something like Paint or Photoshop if you feel fancy.
Hi Brian,
The research area is very interesting indeed. I am sure someone from tobii can tell you what was the youngest age where a P10 was successfully used.
So far, I have always used the point stimulous and just tried an image instead. I personally didn`t find the default images small as they take one seventh of the screen in average, plus they shrink around the focal point therefore, I think they cannot really be bigger than a certain size. If you still feel that the images offered should be enlarged than use an image processing application. Don`t forget though that any images can be used just have to browse for them.
I don`t know how good is an infant`s periferial sight but if they can only focus up to one foot can they look at a 15" screen from that short distance? As far as I understand, the calibration distance is roughly between 50-70cm because the angle of the trackers at the bottom of the unit. Probably, by changing this angle it is possible to reduce the calibration distance but again, tobii stuff will be able to inform you on that the best for sure.
Chris
pro tobii user
Hello Brian,
This question is probably better suited to be posted at our analysis forum at www.tobiiforum.org, which is dedicated to the use of eye tracking as an analysis tool. We have received your support request through our web support form as well and sent you a detailed response through e-mail.
For everyone else here who might be interested, using the X120 eye tracker at a distance of only 30 cm is not really possible. This is because the hardware and algorithms are optimized for a "normal" usage distance for a computer monitor, which is, as Chris pointed out, around 50-70 cm. For most people, tracking deteriorates rapidly at distances of about 45 cm and lower. The best way to work around this is to somehow place the monitor in front of the eye tracker. The limiting factor will then be the tracking angle, which is limited to about 40 degrees for the X120. If the monitor is placed too close to the eyes, the angle of the gaze will be too great when looking at the corners of the screen, resulting in the eye tracker not being able to "see" the pupils.
Best regards,
Joakim