The device was adapted from a VisionTrack system by IScan/Polhemus and contains two miniature cameras, one for the eye and one for the scene which is connected to a host workstation. When used with human subject such setup provides 0.3 deg. of accuracy according to the manufacturer. Williams et al obtained an accuracy of 2-3 deg. from a single dog when using a special calibration method containing five points located on a cross which was mounted at the tip of the muzzle. Using positive reenforcement the dog was gradually trained to wear and fixate targets which I'm sure wasn't an easy task.
Growing interest in canine cognition and visual perception has promoted research into the allocation of visual attention during free-viewing tasks in the dog. The techniques currently available to study this (i.e. preferential looking) have, however, lacked spatial accuracy, permitting only gross judgements of the location of the dog’s point of gaze and are limited to a laboratory setting. Here we describe a mobile, head-mounted, video-based, eye-tracking system and a procedure for achieving standardised calibration allowing an output with accuracy of 2–3◦. The setup allows free movement of dogs; in addition the procedure does not involve extensive training skills, and is completely non-invasive. This apparatus has the potential to allow the study of gaze patterns in a variety of research applications and could enhance the study of areas such as canine vision, cognition and social interactions.
- Fiona J. Williams, Daniel S. Mills, Kun Guo, Development of a head-mounted, eye-tracking system for dogs, Journal of Neuroscience Methods, Volume 194, Issue 2, 15 January 2011, Pages 259-265, ISSN 0165-0270, DOI: 10.1016/j.jneumeth.2010.10.022. (available from ScienceDirect)