To record and utilize gaze point data from a Tobii eye tracker, you must declare the eyetracker element in your script 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 receives 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.
Sample scripts for the Tobii Plugin can be downloaded from the Millisecond Test Library.
The Inquisit Tobii Plugin retrieves 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 occurrence 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. |