Interpreting the Tobii HTC Vive eye tracking data

[Zoltan Nadasdy]

Could someone help interpreting these data types that the SDK generates during eye tracking?
The HDM is clear, it references the data relative to a head centered coordinate system.
However, not sure what Left eye Gaze direction and GazeRayWorld represent?

-Left
*Gaze Direction
*Gaze Origin
*GazeRayWorld
~Origin
~Direction

-Right
*Gaze Direction
*Gaze Origin
*GazeRayWorld
~Origin
~Direction

-CombinedGazeRayWorld
*Direction
*Origin

-LeftEye
*Unitvector
*PositionInHMDCoordinates

-RightEye
*Unitvector
*PositionInHMDCoordinates

[Grant [Tobii]]

Hi @znadasdy can you kindly confirm exactly which SDK you are using?

The Unity SDK as designed for the HTC Vive has documentation which describes the various data types @ https://vr.tobii.com/sdk/develop/unity/documentation/api-reference/ such as:

GazeRay – a Unity Object containing 3 values of origin (3d vector for gaze point of origin), direction (3d vector describing gaze direction) and validity

But a number of the types you references are not aligned with this SDK, so further details would be very useful, thanks!

[Amit]

Following is a sample output from the Tobii Pro SDK Prefabs used with Unity (http://developer.tobiipro.com/unity/unity-sdk-reference-guide.html)
#Unity Data
GazeDirection Value=”(-0.05267334, 0.01541138, 0.99848940)” Valid=”True” />
<GazeOrigin Value=”(-0.03057870, 0.00478235, -0.04329382)” Valid=”True” />
<PupilDiameter Value=”0.00168019″ Valid=”True” />
<GazeRayWorld Origin=”(-0.40116220, 1.04663500, -0.38193990)” Direction=”(0.24876200, 0.05519217, 0.96699090)” Valid=”True” /

#Raw Data
<GazeDirection UnitVector=”(0.05267334, 0.01541138, 0.99848940)” Validity=”Valid” />
<GazeOrigin PositionInHMDCoordinates=”(30.57870000, 4.78234900, -43.29382000)” Validity=”Valid” />
<Pupil PupilDiameter=”1.68019100″ Validity=”Valid” />
PupilPosition PositionInTrackingArea=”(0.55140850, 0.63337760)” Validity=”Valid” />

Which one of these can be used to 1) determine head orientation of the user wearing the HMD and 2) Screen co-ordinates where the user is looking in a Skybox playing 360 degree video?

I forgot to mention this part of the output:
<Pose Position=”(-0.26140150, 0.93376760, 0.11820720)” Rotation=”(0.00575974, 0.11311300, -0.00657768, 0.99354370)” Valid=”True” />

[Grant [Tobii]]

Hi @amithirway, the Tobii Pro SDK Unity Bindings is part of the Tobii Pro business department.

This forum is intended for support with the Tobii Tech Consumer level eye trackers (4C, EyeX, HTC Vive, etc) and their associated SDK’s including the XR SDK for Unity.

Please get in touch with Tobii Pro Support team directly @ http://www.tobiipro.com/contact/contact-support/ for an answer to your query.

Apologies for the inconvenience and thanks for your understanding.

[asish]

How can I show/store eye blinking data using vive pro? Anyone can help me or provide sample code?

[Grant [Tobii]]

Hi @asishcse, thanks for your query. The Tobii XR SDK has blink detection algorithms available for which you can read more @
https://vr.tobii.com/sdk/develop/unity/documentation/usage-examples/

[Author]

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