5 Eye Tracking Data

There are a few extra Data Preparation steps required for pupil data.

The eye tracker will create several data files that we need to import into BeGaze analysis software and export as a .txt file. The following data files are created by the eye tracker

  • .idf - this file contains the actual gaze and pupil data

  • AccuracyImage.bmp - An image file

  • TrackingMonitorImage.bmp - An image file

  • .idf_images - These files will look like folders. We do not need to import these files

In Step 1 of Data Preparation these files were added to the Z Drive: Z:/Backup Data/[STUDY NAME]/Subject Files/[Task Name]/idf

5.1 Copy from Z Drive to the Lab Backup Hard Drive

  1. Copy the files from the Z Drive to the Lab Backup Hard Drive

    Z:/Backup Data/[STUDY NAME]/Subject Files/[Task Name]/idf

    Lab Backup (D:)/[STUDY NAME]/[Task Name]/Raw Data/idf

5.2 BeGaze

  1. Delete Experiment in BeGaze

    Got to File -> Delete Experiment from Data Base

    • Delete ET_Data Experiment

  2. Open data files in BeGaze

    • File -> Manual Experiment Creation

    • Experiment Name: ET_Data

    • Go to the Gaze Data tab:

      • Navigate to Lab Backup (D:)/[STUDY NAME]/[Task Name]/Raw Data/idf

      • Check if any subject files have a different recording frequency (Hz) or different calibration screen resolution (e.g. [860,720])

      • Select those subject files and click “Remove Files”

      • On the computer in the idf folder, move all the files associated with those subjects to a “recording error” folder: Lab Backup (D:)/[STUDY NAME]/[Task Name]/Raw Data/idf/recording error

      • Check that all subjects have the same recording frequency (Hz) and calibration screen resolution.

    • Go to Stimulus Images tab:

      • Add Files… -> select the  AccuracyImage.bmp  and  TrackingMonitorIMage.bmp  files you want

    • Go to Event Detection tab:

      • Set Event Detection to: High Speed

      • Set the following parameters:

        • 22 ms

        • 40%

        • 50 ms

        • 20%

        • 80%

    • Select Create Experiment


  1. Convert .idf files to .txt files

    • Export -> Legacy: Export Raw Data to File…

    • The following fields should be selected (Fields with an * are the most important)

      Raw Data:

      • Pupil Diameter

      • Pupil Diameter [mm] *

      Channel:

      • Left Eye *

      • Right Eye *

      Points of Regard (POR):

      • Gaze Position *

      • Quality Values

      • Eye Position

      • Gaze Vector

      Misc. Data:

      • Messages *

      • Event Info *

      • Stimulus

      • Stimulus Conditions

    • Select Details tab

      • Select Write header

      • Decimal places: 4

      • Separator: Tab

      • Export Location: NEEDS TO BE SPECIFIED!! 

        • Browse: Lab Backup (D:)/[STUDY NAME]/[Task Name]/Raw Data

      • Select Single file output

    • Select Export

    • Wait for export to finish

  2. Close Experiment in BeGaze

    • Go to File -> Close Experiment

  3. Move idf files to Processed

    • Move idf files you just processed to idf/Processed

  4. Repeat steps 1 - 5 for each eye tracking task