Eye tracking
Varjo’s built-in eye tracking allows to record and study eye movements in applications. Eye tracking also enables the use of foveated rendering.
Calibrating foveated rendering
Foveated rendering
XR-4, XR-3, VR-3, and Varjo Aero
Foveated rendering uses the eye tracking functionality built into your headset to improve the performance of applications and produce a better virtual experience.
With foveated rendering, the area with the highest image resolution follows your gaze so that you can always experience the best possible image quality. Simultaneously, your headset can render fewer pixels in peripheral areas, improving application performance.
Note that foveated rendering is enabled only in applications that support the feature. For more information on enabling foveated rendering in applications, see our Developer portal.
Calibrating foveated rendering
By default, foveated rendering is calibrated whenever you put on the headset. For best results, make sure to position the headset correctly when you put it on. Foveated rendering is calibrated by focusing your gaze on a dot shown on the headset screen for a brief moment.
In Varjo Base you can choose how often foveated rendering is calibrated. Navigate to the Headset tab and Foveated rendering. The following options are available:
| Always calibrate | Foveated rendering is recalibrated whenever you put on the headset.
This option is best suited for situations where several people share a headset and provides the best possible image quality. |
| Remember my calibration | Foveated rendering is calibrated once. Your calibration settings are saved and reused in future sessions.
This option is most useful when only one person is using the headset. |
| Best estimation without calibration | Foveated rendering is calibrated using data from a statistical sample.
This option works best when several people are using the headset in quick succession. Note that without calibration, eye tracking accuracy is not sufficient for the most demanding applications. |
| Never calibrate | Foveated rendering is not calibrated. The area with the highest resolution is locked to the center of the display.
This option can be a useful fallback if, for example, you cannot complete calibration with certain types of eyeglasses. |
Using eye tracking
Varjo’s integrated eye tracking is available for using with all Varjo headsets, and allows to follow the headset user’s eye movements with a sub-degree accuracy.
The eye tracking has been designed to work with most single-vision eyeglasses. However, the technology is not guaranteed to work with all medical devices or eye conditions.
Calibrating eye tracking
Eye tracking calibration is done by following a moving dot with your eyes. This sequence typically takes less than 30 seconds.
For eye tracking to work accurately, position the headset correctly so that the cameras can see your eye movements. Make sure that the headset stays firmly in place while you are wearing it and that the image looks sharp. The headset may show you additional instructions on how to correctly position the headset before calibration starts.
Your application can be programmed to start the calibration automatically. You can also start the calibration manually. See instructions below depending on your headset model.
XR-4, XR-3, VR-3, and Varjo Aero
Depending on your use case, often the quick calibration for foveated rendering can be sufficient for good quality eye tracking. For more accurate eye tracking, navigate to the Tools menu in Varjo Base, select Analytics window and choose Eye tracking > Calibrate.
If you have turned on Remember my calibration in Varjo Base, you don’t need to calibrate between sessions.
XR-1 Developer Edition, VR-2 Pro, VR-2, and VR-1
Choose one of the following to start eye tracking calibration:
- in Varjo Base in the Tools menu, select Calibrate eye tracking
- in Varjo Base settings, navigate to Headset tab and choose Eye tracking calibration > Start
- in the headset Menu, select the shortcut for Calibrate eye tracking
Visualizing eye tracking
When hosting a session in Varjo Base, it can be helpful to know where the headset user is looking. You can visualize the headset user’s gaze movement by selecting Gaze dot below the headset view in Varjo Base.
Exporting eye tracking data
Varjo Base can save eye tracking data alongside a recording of the headset view. This can be useful for analyzing a session afterwards.
Please note that you must calibrate eye tracking before saving eye tracking data.
From the Tools menu, open the Analytics window and click on the icon in the bottom left corner to open the toolbar. Select Eye tracking and enable the option to Log eye tracking data while screen recording. Click on Screen recording to start.
Both a data file containing eye tracking data and a video file of the headset view are automatically saved in C: > Users > username > Videos > Varjo folder on your Windows computer. The data file is in CSV format and contains a timeline of the recording with x-y coordinates for gaze positions.