Algorithm used in FixationDataStream?

[Siavash Mortazavi]

Hi,

Tobii Studio has these three algorithms for filtering raw gaze data and detecting fixations:

• I-VT filter
• Tobii fixation filter
• ClearView Fixation filter

Could you please tell us which one is implemented for EyeX FixationDataStream?
And could you also please provide us with the values of parameters used for the algorithm, in Sensitive and Slow mode?

If the filter is I-VT, what are the values for the parameters in the following image, in the implemented algorithm?
http://1drv.ms/1vnrlrK

If the filter is Tobii fixation filter, what are the values for the parameters in the following image, in the implemented algorithm?
http://1drv.ms/1vnrMCB

And finally, if the filter is ClearView, what are the values for the parameters in the following image, in the implemented algorithm?
http://1drv.ms/1rWN8ft

We’re using FixationDataStream in academic research, therefore we have to provide some information about the algorithm that is used, alongside with its parameters in our paper.

Thank you,
Sia

[Robert [Tobii]]

Hi Sia,

There is no exact relation between any of the fixation filters in Tobii Studio and the fixation data stream in the EyeX Engine.

The main reason is that Tobii Studio uses an offline filter, i.e. the fixations are calculated after the eye tracker data recording is finished. The EyeX Engine calculates fixations in real-time, which makes it harder to detect fixations in the same robust way as Tobii Studio. Moreover, the EyeX Engine is adapted to consumer-grade eye trackers which might not always provide a stable stream of coordinates. If you’re doing academic research and have access to the complete recording, I would not recommend to use a real-time fixation filter.

[Siavash Mortazavi]

Hi @roberttobii,

Thank you very much for the explanation.

[Cuong Nguyen]

Robert, I am working on a project that needs the real-time fixation data from the EyeX Engine. Would it be possible that you can describe or provide a citation for the algorithm used in FixationDataStream?

Thank you,
Cuong

[Jenny [Tobii]]

Hi Cuong,

The algorithm used in FixationDataStream is proprietary, so there is no public documentation of how it works.

/Jenny

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