The Inquisit Tobii Plugin

Programming the Plugin

To record and utilize gaze point data from a Tobii eye tracker, you must declare the eyetracker element in your script and and set the plugin to "tobii":

<eyetracker>
/ plugin = "tobii"
</eyetracker>

Once the eyetracker is defined in the script, whenever the script is run Inquisit loads the plugin and attempts to locate the Tobii eye tracker on the network. Once connected, the plugin recieves and records the stream of gaze point data from the eye tracker. For dynamic task paradigms that change based on gaze point data, you can programmatically access gaze point data from the properties of the eyetracker element.

The Eye Tracker Element

Sample Scripts

Sample scripts for the Tobii Plugin can be downloaded from the Millisecond Test Library.

Eyetracker Data Recorded by the Plugin

The Inquisit Tobii Plugin retreives and records the following data from the Tobii eye tracker. For more details on a given data field, see the Tobii documentation.

date The date at the start of the session.
time The time at the start of the session.
groupid Group id entered for this session.
subjectid Subject id entered for this session.
timestamp The value should be interpreted as a time interval in microseconds measured from an arbitrary point in time. The source of this timestamp is the internal clock in the eye tracker hardware.
marker A value sent by Inquisit to indicate the occurence of a significant event (e.g., onset of a visual stimulus)
leftpixelx The horizontal pixel location in display coordinates of the gaze point of the left eye.
leftpixely The vertical pixel location in display coordinates of the gaze point of the left eye.
rightpixelx The horizontal pixel location in display coordinates of the gaze point of the right eye.
rightpixely The vertical pixel location in display coordinates of the gaze point of the right eye.
focuspixelx The horizontal pixel location in display coordinates of the gaze point of binocular focus.
focuspixely The vertical pixel location in display coordinates of the gaze point of binocular focus.
leftgazex X coordinate of the gaze point of the left eye in the 3D User Coordinate System.
leftgazey Y coordinate of the gaze point of the left eye in the 3D User Coordinate System.
leftgazez Z coordinate of the gaze point of the left eye in the 3D User Coordinate System.
rightgazex X coordinate of the gaze point of the right eye in the 3D User Coordinate System.
rightgazey Y coordinate of the gaze point of the right eye in the 3D User Coordinate System.
rightgazez Z coordinate of the gaze point of the right eye in the 3D User Coordinate System.
lefteyex X coordinate of the location of the left eye in the 3D User Coordinate System.
lefteyey Y coordinate of the location of the left eye in the 3D User Coordinate System.
lefteyez Z coordinate of the location of the left eye in the 3D User Coordinate System.
righteyex X coordinate of the location of the right eye in the 3D User Coordinate System.
righteyey Y coordinate of the location of the right eye in the 3D User Coordinate System.
righteyez Z coordinate of the location of the right eye in the 3D User Coordinate System.
leftpupilwidth Width of the left pupil in millimeters
leftpupilheight Height of the left pupil in millimeters.
rightpupilwidth Width of the right pupil in millimeters.
rightpupilheight Height of the right pupil in millimeters.
leftvalidity An estimate of how certain the eye tracker is that the data given for the left eye really originates from that eye, with 0 indicating the eye was definitely found, and 4 indicating the eye was not found.
rightvalidity An estimate of how certain the eye tracker is that the data given for the right eye really originates from that eye, with 0 indicating the eye was definitely found, and 4 indicating the eye was not found.