To allow for a broader and more direct use of the Tobii EyeX device in scientific research, we have implemented a software Toolkit in Matlab which interfaces with the eye tracker controller. The Matlab Toolkit consists of four parts: 1) a client UDP (User Datagram Protocol) interface to connect Matlab with the Tobii server, 2) a set of basic connection functions for data transmission and reception, 3) a set of routines for standard use of the device, and 4) sample code provided to exemplify the usage of each function of the Toolkit in simple experiments in which we measure saccade, smooth pursuit, vergence and fixational eye movements. The graphical interface of the Toolkit has been implemented exploiting the Psychophysics Toolbox Version 3 (Kleiner et al. 2007 ; Brainard 1997 (link); Pelli 1997 (link)). The client UDP interface has been developed via the Tobii Gaze SDK, thus allowing the Toolkit to be compatible with other eye tracking devices produced by Tobii such as the Tobii Rex and Tobii Steelseries Sentry.
The quality of eye tracking data in scientific experiments may be affected by both the subject and the operator (Nyström et al. 2013 (link)). Level of compliance to task instructions, variable environment illumination, glasses or contact lenses, makeup and eye physiology are all relevant factors with regards to the eye tracking data quality. To allow for a rapid online evaluation of gaze data quality, the Toolkit implements routines that resemble and extend the functionalities provided by the Tobii EyeX Engine. In particular, we provide routines to: 1) correctly position the user with respect to the screen; 2) calibrate both binocular and monocular gaze measurements, 3) visually check the outcome of the calibration. Moreover, we also release the code used to evaluate accuracy, precision and sample frequency of Tobii EyeX, which can be easily adapted to other eye tracking devices. A detailed description of the Matlab Tookit is provided in AppendixA .
The quality of eye tracking data in scientific experiments may be affected by both the subject and the operator (Nyström et al. 2013 (link)). Level of compliance to task instructions, variable environment illumination, glasses or contact lenses, makeup and eye physiology are all relevant factors with regards to the eye tracking data quality. To allow for a rapid online evaluation of gaze data quality, the Toolkit implements routines that resemble and extend the functionalities provided by the Tobii EyeX Engine. In particular, we provide routines to: 1) correctly position the user with respect to the screen; 2) calibrate both binocular and monocular gaze measurements, 3) visually check the outcome of the calibration. Moreover, we also release the code used to evaluate accuracy, precision and sample frequency of Tobii EyeX, which can be easily adapted to other eye tracking devices. A detailed description of the Matlab Tookit is provided in Appendix
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